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1. 3 59 MEFI 2 Codes 3 59 MEFIS Codes 2 6 3 EE 3 60 Injector Balance Test Multi Port Models 3 62 Test Procedure 3 62 Test Example 3 63 ECM Connector and EFI Symptoms Chart MEFI 3 Big Block V8 All other MEFI s Similiar 3 64 ECM Connector and Symptom Chart MEFI 3 Big Block V8 J 1 Circuits 3 65 ECM Connector and Symptom Chart MEFI 3 Big Block V8 J 2 Circuits 3 67 PCM ECM 555 Diagnostics 3 69 ECM 555 Troubleshooting Preliminary Checks 3 75 Visual Physical Checklist 3 75 On Board Diagnostic OBD System Chart 555 3 76 555 System Engine Fault Quick Reference Chart 3 78 Gen Cool Fuel Module Diagnostics 3 83 MerCruiser EFI 0804 MerCruiser EFI Tool List Fuel System Tools Fuel pressure gauge set Adaptor fitting set MT337 300 Snap On Replacement seals for adapter fittings Snap On GM test port seal large MC Schrater test port seal small O ring TBI adaptor fitting with tire valve fitting Fuel line adaptor with nipple fitting Fuel line shut off tool MPI injector noid light Bosch connector GM TBI injector noid light Fuel line disconnect tool set 3 g fuel supply at rail 5 46 fuel return plug at rail Portable 6 6 gal Fuel Tank Cole P
2. REDIBLK 121 3 TACH CIRCUIT DESCRIPTION MerCruiser EFI I CKT 430 PPLAWHT is where the Distributor Reference HIGH RPM signal is sent to the ECM When the system is running on the ignition module or in crank mode there is no voltage on CKT 424 and the ignition module grounds CKT 423 The ECM expects to detect a low voltage on CKT 423 during this condition If the ECM sees voltage it sets Code 41 and will not go into the Ignition Control IC mode When the rpm for IC is reached about 300 rpm and CKT 424 voltage applied CKT 423 should no longer be grounded in the ignition module and the voltage should be varying If CKT 424 is open or grounded the ignition module will not switch to IC mode The CKT 423 voltage will be low and Code 42 will be set If CKT 423 stays grounded the IC module will switch to IC mode but because the line is grounded there will not be an IC signal and a trouble code 42 will be set 1003 EFI SYSTEM COMPONENTS OPERATION 2 43 EFI Engines with Mercury Marine Thunderbolt V Distributor and MEFI 3 ECM 1999 V 6 and Small Block V 8 Engines These EFI MPI engines V 6 Small Block V 8 originally used an EST type of distributor They now use 1999 and later a Mercury Marine Thunderbolt V style distributor This unit only has an ignition sensor It does not have an ignition module like the EST system The sensor provides a square wave digital signal to the ECM whi
3. Figure 1 1 DMT2000A and Interface Module MerCruiser EFI I 1003 DIAGNOSTICS 3 7 Tachometer Secondary Inductive Pick Up IMPORTANT Use the 2STR range for tachometer testing on the Mercury Mariner 4 Stroke Outboards Refer to DMT2000A information in this User s Manual for addi tional information and instructions PROCEDURE 1 Plug interface module into DMT2000A meter refer to Figure 1 2 Red lead plugs into the VQHz port and the Black lead into the COM port Plug Inductive Clamp P N 91 854010 into interface module with lead marked to Red port and lead marked to Black port Position rotary function knob to IP RPM Inductive Depress RANGE button to select 2STR or ASTR See important above Clip Inductive Clamp to high tension spark plug lead Read RPM on DMT2000A Display 3 8 DIAGNOSTICS Figure 1 2 DMT2000A With Filter and Inductive Clamp MerCruiser EFI 1003 Direct Voltage Adapter DVA Optional Accessory P N 91 89045 PROCEDURE 1 Plug Direct Voltage Adapter into DMT2000A meter refer to Figure 1 3 Red lead plugs into the VOHz port and the Black lead into the COM port 2 Plug Test Leads into Voltage Adapter with Red lead into Red receptacle and Black into Black receptacle 3 Position rotary function knob to DC Voltage scale indicated by V DMT 2004 VHz 4 Read DC Voltage on DMT2000A Display Figure 1 3 DMT2000A with Direct Vol
4. Bravo 1 2 or 3 320 pshp 4600 5000 rpm MX 6 2 MPI Horizon Bravo 1 2 or 3 320 pshp 4600 5000 rpm 350 Magnum Inboard 300 pshp 4400 4800 rpm 350 Magnum MPI Horizon Inboard 300 pshp 4400 4800 rpm MX 6 2 MPI Inboard 320 pshp 4600 5000 rpm 6 2 MPI Horizon Inboard 320 pshp 4600 5000 rpm 350 Magnum MPI Tow Sports 315 pshp 4600 5000 rpm NOTE All new models listed for the 2002 model year use the GM Intake Air Fuel Module IAFM and Mercury Marine ECM 555 These models produced in limited numbers only and were phased out as listed new models became available VVVVVVVVY Service Notes SB 2001 1 MerCruiser Scan Tool SB 2001 2 Quicksilver DDT Scan Tool SB 2001 4 Priming Fuel System SB 2001 5 496 Mag 8 1S Fuel Line and Fuel Rail Outlet Plug SB 2001 6 Required 496 Mag HO 8 1S HO Push Rod Replacement SB 2001 14 Required 496 Mag 8 1S Engine Electrical System Repair SB 2001 15 New Gasoline EFI MPI Engine Fogging Procedure SB 2001 16 Required MIE 8 1 8 1 HO PCM 555 Replacement 2003 Model Year MerCruiser EFI I 1003 Model Line Summary from product line brochure Sterndrives 4 3 MPI Alpha Bravo 2 or 3 220 pshp 4400 4800 rpm 5 0 MPI Alpha Bravo 1 2 or 3 260 pshp 4600 5000 rpm 350 Mag Alpha Bravo 1 2 or 300 pshp 4600 5000 rpm 350 Mag MPI Horizon Bravo 1 2 or 3 300 pshp 4600 5000 rpm 6 2 MPI Bravo 1 2 or 3 32
5. NT a 3 m xxe i T SPLICE 105 7 zd cz ES amp 72 gt gt m WHT BLK F OG il C BA PORT COILS CRANK With initial key ON 12 volt power is sent from the battery through the purple lead in the 10 pin harness to the pink lead at Engine Harness Pin C This is wake up power to the PCM The PCM powers pin B4 which in turn pulls the MPR low The MPR powers the coils through Splice 105 and powers the engine for ignition 77672 2 40 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI 1003 PCM 555 COIL HARNESS CIRCUIT RED m 12 BLK in 9 O D EF G H U a ANd ANd w B AX HNd HNd SPLICE SPLICE BRN PNK PNK PUR BRN ABCD 77695 Coil Harness To Engine Harness Connector b 1 And 8 Coil Connector c 3 And 6 Coil Connector d 5 And 4 Coil Connector e 7 And 2 Coil Connector There are 2 coil harnesses on the engine one for each side of the engine The harnesses are wired identically The signal wire color for coils 1 and 8 is BLU coils 3 and 6 is PUR 5 and 4 wire is GRN and 7 and 2 is RED The PNK wire is 12 volt power the BRN wire is 5 volt power and the BLK wire is ground If a possible problem is suspected in the ignition system check for faults once with key ON and once with engine running An EST Open will only register a fault in a key ON only sta
6. SWITCH TO AUDIO TAN BLU WARNING HORN TO TEMP GAUGE TAN TOIGN lt PUR 76082 4 18 WIRING DIAGRAMS MerCruiser EFI 1003 PCM 555 Charging Harness O3u 13A 2 7 mer SX a w 042 o gt 2 E gt lt E GRY gt TAN y 2 if I v LL _ i d in TANBLU oc i a L BLU TAN y I Wa a J u PEN K Z gt ORA fF y m YEL RED a eje 2 oT n EH ORA V D 3 PPL u TS c Pa ee ED e n RED PPL m _ o PERS i BLK z O A RED PPL e s BLK MN d gt a pra m gt m RED PPL mm J T 5 e m g am m q ka c 20 D RS D Z F7 D uH C 22 a 07 BLK DE E YEL BLK L 302 z On r 3 Ils fa I a x BLK wm m z m m m 199 23 J BLU TAN 55 1 D 188 9 LT BLU gt C lt Cm Z BRN WHT NN w r w BRN WHT mme c m gt 2 cas sp O o 77671 MerCruiser EFI 1003 WIRING DIAGRAMS 4 19 555 Ignition Circuit COILS 2 CAM B CE TG H C B A 11 z
7. 1003 DIAGNOSTICS 3 13 Testing Fuel System Pressure EFI Systems 76681 a Fuel Rail Assembly b Intake Manifold c Throttle Body d Fuel Pressure Test Port Testing Boost Pump If so equipped Precautions Always disconnect battery cables from battery BEFORE working on fuel system to prevent fire or explosion careful when changing fuel system components gasoline is extremely flammable and highly explosive under certain conditions Be sure that ignition key is OFF DO NOT smoke or allow sources of spark or flame in the area while changing fuel filters Wipe up any spilled fuel immediately Make sure that no fuel leaks exist before closing engine hatch DO NOT operate engine without cooling water being supplied to seawater pickup pump or pump impeller will be damaged and subsequent overheating damage may result NOTICE BEFORE proceeding refer to Precautions Disconnect battery cables from battery Remove fuel line from outlet side of boost pump or from inlet side of water separating fuel filter 3 Install Fuel Pressure Connector 91 18078 to boost pump or water separating fuel filter and reinstall fuel line Tighten connector and fuel line securely N 3 14 DIAGNOSTICS MerCruiser EFI 1003 4 Connect fuel pressure test gauge 0 15 psi to connector 5 Reconnect battery cables start engine and run at 1800 RPM If engine will not start crank
8. Water Outlet Low pressure pump 7 b To Engine Fuel Rail Fuel Filter Po High Pressure DUE Water Inlet 1st singo dui 10 psi a z Pressure Regulator Water Separating Fuel Filter Water Jacket High Pressure ome Lift Pump Boost Pump 2 86 EFl SYSTEM COMPONENTS OPERATION MerCruiser EFI 0804 Fuel Flow Through the System 2 Story Water Flow Path MerCruiser EFI 0804 EFI SYSTEM COMPONENTS OPERATION 2 87 Cool Fuel System Mounted on Small Block Engine 2 88 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI 0804 Gen III Cool Fuel Module MerCruiser EFI 0804 EFI SYSTEM COMPONENTS OPERATION 2 89 DIAGNOSTICS MerCruiser EFI 0804 Table of Contents Page MerCruiser EFI Tool List 3 1 Fuel System Tools 3 1 Electrical System Tools 3 1 Ignition System Tools 3 1 General Diagnostic Tools 3 2 E 3 2 Tool Manufacturers 3 2 DMT 2000A Complete Kit Description 3 3 Mercury DMT 2000A FAQ S 3 4 DMT 2000A Digital Tachometer Multi Meter Kit 3 6 Meter Connections and Hook Up 3 7 Interface Module Battery Check 3 7 Tachometer Secondary Inductive Pick UB Cay REX 3 8 Direct Voltage Adaptor DVA Optional 3 9 Attaching Alligator Clips 3 9
9. or BlackHawk 385 pshp 4600 5000 rpm 454 Magnum MPI Tournament Ski Inboard 395 pshp 4600 5000 rpm 502 Magnum Bravo 1 2 or BlackHawk 415 pshp 4600 5000 rpm Model Line Changes from ReCertification book Model designation change All throttle body injected TBI models are now simply called EFI models All multi port fuel injected MP or MPI models are now simply called models This model year was a transition year some models were introduced as 1996 1 2 models Some of the 96 1 2 models will use the new Cool Fuel system instead of the standard VST system Gen small block engines use the new GM high flow intake system The heads and intake manifold are new The intake manifold uses only 8 bolts The bolts are completely vertical and are not parallel to the gasket surfaces Theses engines also have composite timing chain covers and 15mm oil pan drain plugs P V6 models will use a cast aluminum oil pan one piece exhaust manifolds and a ser pentine belt system 5 7 L EFI is renamed to 5 7 LX EFI 350 Magnum EFI Tournament Ski Inboard continues 350 Magnum EFI MP Tournament Ski Inboard continues and is renamed 350 Magnum Tournament Ski Inboard 454 and 502 EFI MP models continue and are renamed MPI models Exception the 454 Magnum EFI MP Bluewater Inboard has been dropped Four new big block models 7 4LX Bravo 1 2 or 3 330 psh
10. The following lists the sensors switches and other inputs used by the ECM 555 to control its various systems Although we will not cover them all in great detail there will be a brief description of each m amp wd aa no p E KON EON Lit Lee rere LITE e j e a Key B r DLC b Crank Position Sensor CPS s CAN Line TP t Tach Signal d MAP MAT Fuel Injector Bank f Knock 1 w Fuel Injector Bank B g Knock 2 x EST Module h Lube Oil Bottle y EST Ignition Coil i Sea Pump Water Pressure z Fuel Pump Relay Gear Position aa Cool Fuel Pump k Shift Interrupt bb Main Power Relay MPR Oil Pressure Warning Horn m Transom Harness dd Inputs Pitot ee 555 Controller Steering Angle ff Outputs Fuel Level gg Input Output q Paddle Wheel Sea Temp 2 4 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 34 PCM 555 Input and Sensor Descriptions The following lists the sensors switches and other inputs used by the PCM 555 to control its various systems Although we will not cover them all in great detail there will be a brief description of each 69 10 IH LE EO re Fol a MAP b MAT c TP d ECT e Sea Pump f Oil Pressure g Port EMCT h Starboard EMCT i Lube O
11. 4 3 Typical Starting and Charging System Harness Small Block MEFI 3 A Audio Warning Components 1 Oil Pressure Switch B Instrumentation Components 1 Oil Pressure Sender 2 Trim Sender C Charging and Starting Components Alternator Ground Stud Starter Circuit Breaker Starter Slave Solenoid Jumper Wire Connection Battery B ND a Positive Power Wire To EFI System Harness b Harness Connector To EFI System Harness Auxiliary Tachometer Lead 76061 4 4 WIRING DIAGRAMS MerCruiser EFI 1003 EFI System Harness Typical 3 Throttle Body Injection NOTE All BLACK wires with a ground symbol are interconnected within the EFI system har ness 1 Fuel Pump 14 Fuel Pump Relay 2 Throttle Body 15 Ignition System Relay 3 Distributor 16 Fuses 15 Amp Fuel Pump 15 Amp ECM 4 Coil DLC Battery 10 Amp ECM Injector Ignition 5 Intake Air Temperature IAT Sensor Knock Module 6 Data Link Connector DLC 17 Oil Pressure Sensor 7 Manifold Absolute Pressure MAP Sensor 18 Harness Connector To Starting Charging 8 Knock Sensor Harness 9 Idle Air Control IAC 19 AS Ha Power Wire To Engine Circuit 10 Throttle Position TP Sensor 20 Sum Pisis 11 Engine Coolant Temperature ECT Sensor 12 Electronic Control Module ECM E 13 Water Temperature Sender NOTE Component position and orientatio
12. VDC PWR Low if shorted or no voltage engine will not start if VDC PWR voltage falls velow 22 volts will set sensor faults NOTE 5 Shift Switch will activate code when engine rpm are above 3500 rpm and 40 load 2 20 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 Two Wire Sensors ECT and IAT The following figure is the schematic of a 2 wire type sensor This sensor is basically a vari able resistor in series with a fixed known resistor within the computer By knowing the values of the input voltage and the voltage drop across the known resistor the value of the variable resistor can be determined The variable resistors that are commonly used are called thermis tors A thermistor s resistance varies inversely with temperature TYPICAL SENSOR 2 Wire Sensor ECM SENSOR SIGNAL Limiting Resistor Three Wire Sensors MAP TP and FP The following figure shows a schematic representation of a 3 wire sensor All 3 wire sensors have a reference voltage a ground and a variable wiper The lead coming off of the wiper will be the signal to the Engine Control Module ECM As this wiper position changes the signal voltage returned to the computer also changes TYPICAL SENSOR 3 Wire Sensor MerCruiser EFI 1003 ECM VOLTAGE OUT SIGNAL INPUT SYSTEM COMPONENTS OPERATION 2 21 MerCruiser EFI System Electronic Components MEFI 3 MCM Sterndrive 7 4L MPI Bravo and MIE Inb
13. 7 MAP Sensor 8 Clip 9 Screw 8 32 x 1 4 in 6 mm 10 Pipe Plug 1 8 in hex head 1 22 EFI PRODUCT HISTORY 11 Fuel Rail 12 Schrader Valve 13 Screws 1 4 20 x 1 1 2 in 14 MAT Sensor 15 16 Fuel Lines 17 O Rings 18 Location of Fuel Line From Fuel Pump 19 Pressure Sensor MerCruiser EFI 1003 11 Later Model 350 Mag MPI Throttle Body Assembly 3 MerCruiser EFI I 1003 Later Models 1 Cover 2 Washer 3 Nut 1 4 28 4 Washer 5 Flame Arrestor 6 Throttle Body Assembly 7 Stud 8 Screw 1 4 20 9 Gasket 10 3 16 in Barb Fitting From Fuel Pres sure Regulator 11 Pipe Plug 1 4 18 Socket Head 12 Screw 5 16 18 x 1 1 4 in 32 mm 13 Washer 14 Throttle Body Adaptor Plate 15 Gasket 16 Stud Kit 17 Throttle Cable Bracket 18 Screw 5 16 18 x 1 in 19 Washer 20 Washer 21 Stud 1 4 x 1 3 4 in 22 Nut 1 4 28 EFI PRODUCT HISTORY 1 23 Throttle Body Assembly TBI EFI Models 1 Cap Screw 11 Body 2 Cover Assembly 12 Throttle Body To Fuel Meter Body 3 Fuel Pressure Regulator Gasket 4 Cover Assembly Gasket 13 Throttle Body 5 Upper O Ring 14 Throttle Position TP Sensor 6 Fuel Meter Outlet Gasket 15 Screws 2 7 Fuel Injector 2 16 Seal 8 Fuel Filter 2 17 O Ring 9 Lower O Ring 18 Idle Air Control IAC Valve 10 Screw 19 Screws 2 2
14. Seawater section however must be drained completely A discharged battery can be damaged by freezing 5 2 MAINTENANCE OFF SEASON STORAGE MerCruiser EFI 1003 Seawater section of cooling system MUST BE COMPLETELY drained for winter stor age or immediately after cold weather use if the possibility of freezing temperatures exists Failure to comply may result in trapped water causing freeze and or corrosion damage to engine IMPORTANT Observe the following information to ensure complete draining of cool ing system e Engine must be as level as possible A wire should be repeatedly inserted into all drain holes to ensure there are no ob structions in passages IMPORTANT To prevent threads in manifolds elbows and cylinder blocks from rusting during storage reinstall drain plugs Never leave drain plugs out during storage NOTE If possible place a container under drains and hoses to prevent water from draining into boat Power Package Layup NOTICE Refer to Cold Weather or Extended Storage Precautions in this section BEFORE pro ceeding IMPORTANT Mercury MerCruiser strongly recommends that this service be per formed by an Authorized Mercury MerCruiser Dealer Damage caused by freezing IS NOT covered by the MerCruiser Limited Warranty 1 Fill fuel tank s with fresh gasoline that does not contain alcohol and a sufficient amount of Quicksilver Gasoline Stabilizer for Marine
15. Temperature Probe 3 10 Clamp On Current Probe Optional 3 11 P N 91 805747A2 Timing Tool for MerCruiser EFI Engines 3 12 GODEMATETM ERE RP 3 12 Marine EFI Code Reader Rinda 3 12 Scan TOUS ERE RE 3 12 Older Software and Newer EFI Systems 3 12 Quicksilver DDT Scan Tool New Cartridge 3 12 Testing Fuel System Pressure on EFI Throttle Body Injection Systems 3 13 Fuel Pressure Test Gauge Adaptor FININGS s ss qud Ea b p RR Sb 3 13 Testing Fuel System Pressure on EFI Systems 3 14 Testing Boost Pump If so equipped 3 14 Precautions 3 14 Testing Mechanical or Electric Fuel Supply Pump used on VST models 3 16 Precautions 3 16 Throttle Body Injection With Vapor Separator Tank VST 3 17 Checking for Restrictions Vapor Lock Problems in Fuel Delivery Systems 3 18 Equipment Used to Test Fuel RVP Fuel Temperature or Fuel System Vacuum 3 20 Delco EST Ignition Troubleshooting 3 22 Erratic Spark Symptoms 3 22 No Spark Troubleshooting 3 22 3 with Mercury Marine Distributor Ignition System Troubleshooting 3 24 Non Scan Diagnosis of Driveability Concerns With No Codes Set 3 25 Out of Range Sensors 3 26 Scan Tool Use Wit
16. There are 2 coil harnesses on the engine one for each side of the engine The harnesses are wired identically The signal wire color for coils 1 and 8 is BLU coils 3 and 6 is PUR 5 and 4 wire is GRN and 7 and 2 is RED The PNK wire is 12 volt power the BRN wire is 5 volt power and the BLK wire is ground If a possible problem is suspected in the ignition system check for faults once with key ON and once with engine running An EST Open will only register a fault in a key ON only state and an EST Short will only register with the engine operating A malfunction in the coil harness will set the fault of EST 1 8 Open or EST 1 8 Short MerCruiser EFI 1003 WIRING DIAGRAMS 4 21 MAINTENANCE OFF SEASON STORAGE MerCruiser EFI 0804 Table of Contents Page IGNITION Timing 222 see rrena ki 5 1 System EFI MPI Models 5 1 555 System Models 5 1 Cold Weather or Extended Storage 5 2 Se riviere messes 5 2 Power Package Layup 5 3 5 1 MAINTENANCE OFF SEASON STORAGE MerCruiser EFI I 1003 Ignition Timing MEFI System EFI MPI Models 1 Connect timing light to number 1 spark plug wire Start engine and run at 1300 rpm until it reaches normal operating temperature Stop engine and connect the scan tool or timing tool to the DLC connector on the EFI MPI wiring harness 4 Start engine allow rpm to stabilize NOTE MEFI
17. sors would cause the ECM to provide a leaner fuel air ratio to the engine ACCELERATION MODE Rapid changes in Throttle Position Sensor TP and Manifold Absolute Pressure Sensor MAP signals to the ECM will cause the ECM to provide extra fuel to the engine The ECM achieves this by holding the fuel injectors OPEN for a longer period of time CLEAR FLOOD MODE If an EFI engine floods it can be cleared by positioning the throttle one half to three quarters open When the TP sensor reads between 50 and 75 at cranking rpm the will not fire the fuel injectors at all This will allow air to be drawn into the engine but no fuel injected As soon as the engine starts and exceeds 300 rpm the ECM cancels the clear flood mode and enters running mode Not active on ECM PCM 555 equipped engines 2 26 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 FUEL CUTOFF MODE The cuts off fuel delivery to the engine when the key is off to prevent dieseling when no distributor reference pulses are sent means the engine is not running and at high engine RPM overspeed protection DECELERATION MODE The Idle Air Control Valve IAC is similar to a carburetor dashpot It provides additional air when the throttle is rapidly moved to the idle position to prevent the engine from stalling POWER REDUCTION MODE 1995 AND EARLIER EFI ENGINES EARLY MEFI 1 The two discrete switch inputs and the ECT engine coolant temperature se
18. that bypasses the throttle valves through the idle air passage in the throttle body It also pre vents stalls due to a change in engine RPM The valve moves in and out of the idle air passage to decrease or increase air flow as required KNOCK SENSOR 7 The Knock Sensor is mounted in the lower side of the engine block When abnormal engine vibrations occur because of spark knock the sensor produces a signal that is sent to the ECM Problems in this system could set a 43 or 44 failure code 2 24 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 DISCRETE SWITCH INPUTS 4 17 Two discrete switch inputs are used to identify abnormal conditions that may effect engine operation a low oil pressure switch and low drive unit fluid level switch are wired to the ECM They signal the module of low oil pressure or low drive unit fluid Both discrete switches are in a normal open mode when the engine is running The warning horn will sound if there is a problem Inboard models use a transmission temperature switch instead of the low drive unit fluid level switch If the transmission temperature gets too high the switch will signal the ECM of this condition The following are additional sensors used on the PCM 555 EFI System EXHAUST MANIFOLD COOLANT TEMPERATURE SENSORS EMCT There are two Exhaust Manifold Coolant Temperature Sensors EMCT one in each exhaust manifold port and starboard They are located at the mounting flange be
19. 1 2 ft 2 3 2 9 m Lu 9 1 2 12 ft 29 3 7 m 12 15 ft 3 7 4 6 m 15 19 ft 4 6 5 8 m 0000 120mm DIESEL ENGINES MerCruiser EFI I 1003 Cable Length Cable m 4 3 4 6 ft erum a e Two cables of specified gauge required for positive and two required for negative GENERAL INFORMATION 6 7 With the old battery cable recommendation the negative and the positive battery cables were measured separately and then select the correct cable gauge to fit the length measured for each This was OK if they were both the same length It did not work well if there was a battery switch installed in the positive battery cable between the engine and bat tery Then the positive cable had to use a much larger gauge than the negative did In the example below this would have meant the shorter 36 in 91 4 cm length negative would have used a 4 25mm gauge cable The longer 228 in 579 1 cm positive cable would have used 0000 120mm gauge EXAMPLE A person measures 36 in 91 4 cm length of negative cable between engine and battery They measure 108 in 274 3 cm of positive cable between the engine and the battery switch and 120 in 304 8 cm between the battery switch and battery Add 36 in 91 4 108 in 274 3 120 in 304 8 cm 264 in 670 5 cm divide by 2 132 in 335 3 cm or 11 ft 3 4 m So BOTH the negative AND positive batte
20. 1 3 P N 91 880118 003 3 12 DIAGNOSTICS MerCruiser EFI I 1003 Testing Fuel System Pressure EFI Throttle Body Injection Systems 91 881833A2 a Remove Fuel Line from Throttle Body Unit and Install Fuel Fitting Connector P N 91 806901 Connect Fuel Pressure Gauge Kit P N 91 16850A7 to test system pressure Fuel Pressure Test Gauge Adaptor Fittings MerCruiser EFI I The following information is contained in revised Service Bulletin 97 24 1998 2000 MCM MIE 7 4L MPI L29 uses a different size and type of test port valve on it for checking the fuel pressure at the fuel rail The older Fuel Pressure Gauge Kit P N 91 16850A 2 will not attach to this valve A new kit has superseded this kit and it contains 2 fittings so it will fit both types of test ports and a TBI pressure valve to allow the gauge to connect to TBI engines Quicksilver will also sell an Adapter Kit that can be purchased to update the older 91 16850A 1 2 3 kit This kit comes with both size test port valve adapters and instructions on how to fit it to the older gauge kit 91 881833A 2 Fuel Pressure Gauge Kit Kit contains Adapter Kit and TBI Pressure Valve To update older 91 16850 1 2 YA Fuel Pressure Gauge Kits order the following H 91 806901 TBI Pressure Valve Allows older Gauge Kits to j connect to TBI engines 91 803135 Adapter Kit Allows older Gauge Kits to connect to either type of test port valve
21. 2 TODLC DLC 15A CONNECTOR SYSTEM IGNITION RELAY TO E 2 RED TQ TO 3PNK IGN INJ FUSE 439 1 IGNITION PNK IGNITION TO TO IGN COIL INJECTORS TERM INAL 902 RED TO FUEL PUMP RELAY 496 DK BLU KNOCK SENSOR 1 KNOCK 4396 DK BLU SENSOR 2 L29 ONLY OIL PRESSURE 114 BLU KNOCK 8 SENSOR 1 KNOCK SENSOR 2 L29 ONLY 7 150 BLK 906 TAN WHT GEAR LUBE BOTTLE MCM ONLY SWITCH MCM ONLY 150 BLK 1 GEAR LUBE BOTTLE TRANSMISSION NEUTRAL SAFETY SWITCH MIE ONLY LOAD ANTICIPATION 923 WHT SIGNAL 76081 MerCruiser EFI 1003 WIRING DIAGRAMS 4 17 ECM Wiring Diagram Big V8 4 of 4 450 BLK 41 4 GROUND PICK UP COIL IC MODULE 450 BLK Ji 5 ECM GROUND 450 BLK J1 20 GROUND 423 WHT 41 10 IGNITION CONTROL 430 PUR WHT 2 10 DIST REFERENCE 32 10 8 424 TAN BLK 41 24 BYPASS DIST REFERENCE 453 RED BLK J1 3 LOW 2 WAY COIL JUMPER 7 HARNESS 2 WAY BLACK lt lt CONNECTOR 121 WHT FROM IGNITION N RELAY 2 WAY GRAY CONNECTOR 121 WHT TO IGNITION RELAY 71 26 AUDIO WARNING TERMINAL 86 lt 3 29 mum CIRCUIT TRANSMISSION 985 TAN WHT OVERTEMP SWITCH 208 mmm J1 22 NOT USED TEMP SENDER CONNECTOR HALVES TO TACH lt GRY BLUTAN
22. 853998T 2000 UP GM MerCruiser EFI 0804 EFI SYSTEM COMPONENTS OPERATION 2 81 Gen Cool Fuel System System features e Single Integrated Module Filter pumps pressure regulator and cooler all in one unit Fuel flows through filter before getting to lift pump e More Reliable Fewer components Fewer fuel paths e Better Accessibility e Production Friendly Eliminates installation of separate pre filter at OEM Re usable consumer serviceable filter element Pull element dump water re install continue voyage MerCruiser EFI 0804 EFI SYSTEM COMPONENTS OPERATION 2 83 This system will be standard on e Small Block MPI V8 Bravo e Small Block MPI e Big Block MPI Sterndrive e Big Block MPI It will not be available on e V6 Sterndrive e Small Block Ski e Small Block Alpha System Overview e Water Separating Filter Element e 2pumps Lift amp Pressure Lift pump Gerotor Pressure pump Turbine e Fuel Pressure Regulator New 288 kpa 42 psi regulator O rings seal between OD on regulator and ID in cover rather than a face seal and return hose Regulator dumps excess fuel to inlet side of pressure pump Fuel pressure vs flow characteristics differ slightly from Gen Il requires minor calibration changes e Internal Low Pressure Relief Valve Limits pressure across lift pump to 10 psi 5 psi Dumps fuel to inlet side of filter 2 84 EFl SYSTEM COMPONENT
23. BLK WHT or BLK ee TO ECM 15A CONNECTOR 450 BLK WHT or BLK J1 30 J1 20 BATTERY FUSE 450 BLK WHT or BLK RE 451 WHT BLK J2 22 EE 419 BRNAWHT 31 IGN INJECTOR KS J1 11 MARINE e MODULE 10 AMP 439 PNK BLK or PNK DIAGNOSTIC FUSE CODE TOOL CIRCUIT DESCRIPTION The on board diagnostic system check must be the starting point for any diagnosis Before using this procedure check the ECM and engine grounds for cleanliness and tightness The on board diagnostic system check is an organized approach to identifying a problem created by an electronic engine control system malfunction DIAGNOSTIC AIDS An intermittent may be caused by a poor connection rubbed through wire insulation or a wire broken inside the insulation Check for the following items e Poor connection or damaged harness Inspect the ECM harness and connectors for improper mating broken locks improperly formed or damaged terminals poor terminal to wire connection and damaged harness MerCruiser EFI 1003 DIAGNOSTICS 3 57 On Board Diagnostic System Check Typical MEFI Systems cont ma DEO PROCEED TO Are you using a Scan Tool a Ignition OFF b Install a scan tool en m t c lgnition ON Step 3 Nee d Attempt to display ECM data with the scan tool Does The Scan Tool Display ECM Data Attempt to start the engine Step 4 Chart Did The Engine Start And Continue To Run p A 3 Select Display DTCs with the
24. ECM letting it know if the engine is warm or cold The voltage is high when the engine is cold and low when the engine is warm The ECT is a two wire sensor using a 5 volt signal from the ECM A typical reading is 160 deg and if the sensor fails a 14 or 15 failure code is stored inside the ECM THROTTLE POSITION SENSOR TP 9 The Throttle Position Sensor TP is mounted on the underside of the throttle body assembly As the throttle is opened the TP sends out a changing voltage signal to the ECM so that it can adjust the fuel delivery The TP also signals the ECM when the throttle is opened rapidly so it can add extra fuel for acceleration The TP is a 3 wire sensor using a 5 volt signal from the Signal voltage will vary from 7 volts at idle to 5 volts at wide open throttle WOT If the TP fails the ECM will hold a 21 or 22 failure code INTAKE AIR TEMPERATURE SENSOR IAT 19 The Intake Air Temperature Sensor IAT is a two wire sensor mounted on the under side of the intake air plenum It measures the temperature of the incoming air Low temperature pro duces high resistance while high temperature causes a low resistance A failure with the IAT sensor system will store a failure code of 23 or 25 in the ECM IDLE AIR CONTROL VALVE IAC 8 The Idle Air Control Valve IAC is mounted into the side of the throttle body assembly and controlled by the ECM This valve controls engine idle speed by controlling the amount of air
25. ECM primarily looks at the engine s speed and the intake manifold s air density in order to calculate the correct amount of fuel to inject The engine requires an air fuel mixture of approximately 14 7 to 1 in the combustion cham bers Since the EFI system doesn t control air flow it must determine how much air is flowing through the engine in order to calculate the correct amount of time to fire the fuel injectors The net result is that there must be 1 part of fuel for every 14 7 parts of air going through the engine Since the engine is basically an air pump we know that an engine is capable of pumping a certain maximum amount of air at any specific rpm The actual amount of air it pumps at a specific rpm depends on the density of the air in the intake manifold The air density in the intake manifold will vary depending on rpm throttle plate position and barometric pressure If the air density in the intake manifold is known the actual amount of air flowing through the engine the Air Mass or Mass Air Flow could be calculated This calculated and the actu al air flow is a repeatable function meaning that at a specific rpm and a specific manifold absolute pressure reading the air flow through the engine will always be the same However in the speed density system we do not actually calculate the actual air flow Instead the ECM measures the rpm and the air density then refers to a programmed lookup table in the ECM s EEPROM
26. Fuel Line From Front Of Starboard Fuel Rail To Rear Of Port Fuel Rail 20 Fuel Line From Rear Of Starboard Fuel Rail To Front Of Port Fuel Rail 21 Fuel Line From Cool Fuel System 22 Adapter Block 23 Schrader Valve a VST Equipped System b Cool Fuel System 1 20 EFI PRODUCT HISTORY MerCruiser EFI 1003 20 350 Magnum Gen Tournament Ski Black Scorpion Induction System 1 Flame Arrestor 2 Flame Arrestor Clamp 3 Throttle Body 4 Throttle Body Gasket 5 Manifold Absolute Pressure MAP Sensor 6 Plenum 7 Fuel Rail Fitting 2 8 Fuel Line 9 Screw 2 10 Fuel 2 11 Fuel Damper 12 Fuel Rail Fitting 2 13 Schrader Valve 14 Fuel Line 15 Fuel Injector 8 16 Manifold 17 Engine Coolant Temperature ECT Sensor 18 Inlet Fuel Fitting From Cool Fuel System 19 Fuel Line From Front Of Starboard Fuel Rail To Rear Of Port Fuel Rail 20 Fuel Line From Rear Of Starboard Fuel Rail lt Ne NN To Front Of Port Fuel Rail NS gt Earlier Fuel Hose System 6 b Cool Fuel System MerCruiser EFI 1003 EFI PRODUCT HISTORY 1 21 Later Model 350 Mag MPI Induction System Model MEFI 1 amp 2 Similiar MEFI 3 Models MEFI 1 amp 2 Similar 1 Intake Manifold 2 Gasket 3 Plug 4 Screw 5 16 18 x1 3 8 in 35 mm 5 Fuel Injector 6 O Ring
27. General Diagnostic Tools Hand vacuum pump Mity Vac or equivalent J 23738 A OTC 7059 Rinda CodeMate winky blinky 94008 Rinda MerCruiser scan tool current software version 4 0 94050m Software update for scan tool version 4 0 94056 555 adapter cable 64006 Update for scan tool software and cable 94056 Rinda Diacom PC software and cable Windows Version 94010m Quicksilver DDT digital diagnostic terminal 91 823686A2 MerCruiser DDT cartridge current software version 2 0 91 803999 SmartCraft DDT cartridge version 1 3 91 880118 003 MerCruiser DDT adaptor cable DLC and injector connectors 84 822560A2 SmartCraft MerCruiser DDT adaptor cable ECM PCM 555 ECM s 84 822560A13 or 84 822560A5 and 84 822560T12 OTC replacement boot for DDT OTC 3305 30 OTC printer for DDT OTC 3285 OTC printer cable for DDT 25 pin serial port OTC 212536 OTC PC cable for DDT 9 pin serial port OTC 212535 Standard manifold vacuum gauge Locally available Mechanics stethoscope Locally available 3 of 5 32 I D clear vinyl hose with a 5 32 Tee Locally available 5 16 or 3 8 clear vinyl hose with a hose barb on one endt Locally available Footnotes 1 2 Used to provide source of known quality fuel or to bypass boat fuel system as required Should be used only by trained Marine Technicians and only for short term diagnostic purposes Used for both pressure and vacuum tests Gauge Guard
28. MerCruiser EFI I 1003 DIAGNOSTICS 3 11 P N 91 805747A2 Timing Tool for MerCruiser EFI Engines a Timing Tool b DLC Connector CODEMATE Marine Code Reader Rinda CodeMate serves as both an EFI problem indicator and a spark timing service tool The de vice connects to the DLC in a matter of seconds and alerts the boat owner or technician when EFI problems are detected CodeMate allows diagnostic trouble codes DTC s to be read and when used with a timing light allows the technician to verify set the base ignition timing Available from Rinda Technologies Inc Chicago IL Telephone 773 736 6633 Fax 773 736 2950 Rinda 94008 Scan Tools Older Software and Newer EFI Systems Older scan tool software for the Quicksilver Digital Diagnostic Terminal DDT and MerCruis er Rinda scan tools will not be able to read the information coming out of the newer MEFI 2 and MEFI 3 ECM s If you try to use the older software you will get an error message on the display of the DDT scan tool and you will get incorrect information from a MerCruiser Rinda scan tool Quicksilver DDT Scan Tool New Cartridge The DDT will need MerCruiser cartridge version 2 0 P N 91 803999 to read MEFI 3 ECM s This cartridge can also read data from Thunderbolt 5 ignition used on carbureted models See Service Bulletin 2001 2 A second cartridge will be required to read ECM PCM 555 controllers Order SmartCraft DDT cartridge version
29. S CONNECTOR HALVES TO IGN PUR TAN BLU gt TO AUDIO WARNING HORN TO TEMP GAUGE TAN m BLU TAN gt TO TRANSMISSION TEMP SWITCH TO TACH lt GRY YEL BLK gt 0 TRANSMISSION 76099 MerCruiser EFI 1003 WIRING DIAGRAMS 4 13 Wiring Diagram MEFI 3 with GM EST Distributor V6 and Small Block V8 4 of 4 TO FUEL PUMP RELAY FUSE 440 ORN 2 RED ECM BAT FUSE 4400RN gt TO DLC DLC 15A CONNECTOR Ta El RED SYSTEM IGNITION RELAY TO IGN INJ FUSE m 2 902 439 IGNITION 150 3 PNK BLK 7 TO INJECTORS 902 RED TO FUEL PUMP RELAY TO IGNITION COIL TERM ECM GROUND ECM GROUND ECM GROUND FROM IGNITION IGNITION CONTROL 430 PUR WHT DIST REF HIGH 424 TAN BLK BYPASS 902 RED 453 RED BLK DIST REF LOW TEMP SENDER 121 WHT F 208 BRN LOAD ANTICIPATION TRANSMISSION 901 TAN B 585 TAN WHT 3 PNK ol 29 maaa AUDIO WARNING S CONNECTOR HALVES CIRCUIT TO IGN PUR Di TANBLU J gt TO TEMP GAUGE TAN LE BLU TAN m gt TO TACH lt GRY YEL BLK a J 76099 REV 4 14 WIRING DIAGRAMS MerCruiser EFI 1003 ECM Wiring Diagram Big Block V8 1 of 4 INJECTORS 2 3 5 8 From INJ ECM 481 FUSE BLK 467 DK BL
30. This lookup table will be programmed with the correct fuel injector information for every rpm and density reading The programming engineer has to come up with these figures because the ECM is not actually calculating the Mass Air Flow The speed density system depends on the engine being unmodified from its original produc tion state If we change the volumetric efficiency of the engine in any manner the amount of air flow for a given rpm and air density will change causing the ECM to deliver the incorrect amount of fuel Any modification to the following components will influence the air flow through the engine throwing the speed density system out of calibration 1 Pistons and combustion chambers anything that changes the compression ratio Camshaft changes effecting the valve timing lift and duration Changes to intake and exhaust valve size as well as porting and polishing Installing different intake and or exhaust manifolds cq Installing a different size throttle body and or flame arrestor Mass Air Flow Systems Mass Air Flow systems actually measure the amount of air or Air Mass entering the engine so they generally can compensate for modifications or changes to the air flow through the engine While these systems are generally considered more accurate they are generally not as robust and cost effective as the speed density system Mass Air Flow systems are typi cally used in automotive applications to
31. a default value If at that point a noticeable performance increase is ob served the diagnostic testing code chart for that particular sensor should be followed to cor rect the problem NOTE Be sure to clear each code after disconnecting and reconnecting each sensor Failure to do so may result in a misdiagnosis of the problem MerCruiser EFI 1 1003 DIAGNOSTICS 3 25 Out of Range Sensors Scan Tool Use With Intermittents 3 26 DIAGNOSTICS The scan tool allows manipulation of wiring harnesses or components with the engine not run ning while observing the scan tool readout The scan tool can be plugged in and observed while running the vessel under the condition when the Malfunction Indicator Lamp turns ON momentarily or when the engine driveability is momentarily poor If the problem seems to be related to certain parameters that can be checked on the scan tool they should be checked while running the vessel If there does not seem to be any correlation between the problem and any specific circuit the scan tool can be checked on each position watching for a period of time to see if there is any change in the readings that indicates intermittent operation The scan tool is also an easy way to compare the operating parameters of a poorly operating engine with those of a known good one For example a sensor may shift in value but not set a trouble code Comparing the senor s readings with those of the typical scan tool data
32. connector between the engine and boat harnesses If there is any doubt about the boat harness substitute a shop harness and key switch assembly and rerun the boat If the problem disappears the problem is in the boat harness not the MerCruiser engine harness suitable test harness can be assembled from the following components A B C D MerCruiser 3 foot instrument harness cable part number 84 812475A3 MerCruiser ignition switch assembly part number 54212A7 Use suitable machine screws and nuts to join the switch s ring terminals to the harness s ring terminals then cover the connections with heat shrink tubing A standard piezo warning horn can also be added to provide audible warning of cooling system overheat low crankcase oil pressure and low drive oil level or high transmission temperature MerCruiser EFI 1003 DIAGNOSTICS 3 55 EFI Troubleshooting Guide Systems cont Clearing Codes Codes are automatically erased after the engine has gone through its preprogrammed number of power ups l Scan tools A The Quicksilver DDT requires that the engine be running in order to clear the codes If you at tempt to clear the codes with the engine not running the scan tool will attempt to clear the codes but fail to actually accomplish it B The Rinda MerCruiser Scan tool can clear the codes with the engine running or with the engine in the key on engine off KOEO mode Il Codemate win
33. for this example 300 RPM the ECM considers the engine running and applies five volts on the bypass line to the EST module This energizes the relay and causes the points from the pickup coil as well as the grounding points for the IC Ignition Control line to open see figure Control Mode This connects the IC Ignition Control line to the base of the power transistor and bypasses the ignition module timing control The EST system is now controlled by the IC Ignition Control signal from the ECM and the time at which the spark occurs can be determined by a variable time circuit in the ECM This is called the ECM Control mode COIL MODULE ma LU TL E Filter 3 WHT i Ignition Control IC 85 BRN d PUR WHT Dist Reference zh NE 3 pyra oae d BLKRED mb Dist Reference LOW ECM Control Mode MerCruiser EFI 1003 EFI SYSTEM COMPONENTS OPERATION 2 35 EFI Engines with Mercury Marine Thunderbolt V Distributor and MEFI 3 ECM 1999 V 6 and Small Block V 8 Engines These EFI MPI engines V 6 Small Block V 8 originally used an EST type of distributor They now use 1999 and later a Mercury Marine Thunderbolt V style distributor This unit only has an ignition sensor It does not have an ignition module like the EST system The sensor provides a square wave digital signal to the ECM which is used as an engine speed refer
34. fuel filter Fuel could spray on the hot engine causing fire or explosion Allow the engine to cool down before attempting to remove the water separating fuel filter in the following procedure Be careful when changing the water separating fuel filter Gasoline is extremely flammable and highly explosive under certain conditions Ensure the ignition key is OFF Do not smoke or allow spark or open flame in the area when changing the fuel filter Wipe up any spilled fuel immediately MerCruiser EFI 0804 DIAGNOSTICS 3 83 Ensure that fuel leaks exist before closing the engine hatch 1 Allow the engine to cool down NOTE Mercury MerCruiser recommends that the engine be shut off for 12 hours prior to filter removal 2 Disconnect the Cool Fuel Module harness from the engine wiring harness 3 Turn the key switch to the start position and allow the starter to operate for 5 seconds to relieve fuel system pressure 4 Turn key switch to off position 5 Loosen each filter assembly retaining screw until the screw is disengaged from the Cool Fuel Module Do not remove the filter assembly retaining screws from the filter cap i 5658 a Cool Fuel Module e Fuel filter element b Cool Fuel Module harness f Filter cap c Filter cap and O ring g Cool Fuel Module filter reservoir d Filter assembly retaining screw 6 Unseat filter assembly by grasping filter assembly handle and pulling upward Do not remov
35. fuel filter fitting port Installing it on the inlet side will check the fuel tank to filter supply line and hardware anti siphon valve fuel fittings etc Installing it on the outlet side will check the supply line hardware and the filter If the outlet vacuum read ing is higher than the inlet reading the filter is clogged If both readings are high then inspect the fuel tank supply line and hardware Check for trash in the tank blocking the pick up clogged fuel filter screens on the end of pick up tubes in the tank clogged in line fuel filters blocked off fuel tank vent bent pick up tube dirt and debris in fuel fittings wrong size fuel fittings undersize connector fittings undersize fuel shut off valve passages etc undersize fuel line or a malfunctioning anti siphon valve Digital Vacuum Gauge T Fitting Clear hose can be used 4 to check EFI for air Ls M mes Fuel System bubbles y gr y Fuel Pump Mechanical or Electric depending on Fuel System V Water Separating Fuel Filter Fuel Tank There is a MerCruiser specification for allowable vacuum when measured at the inlet side of the engine mounted MerCruiser Water Separating Fuel Filter or if there is none mounted on the engine at the inlet side of a fuel pump Use digital vacuum gauge an analog gauge may not give accurate enough readings at these low levels that reads in either in Hg inches of mercury or kPa kilopascals
36. gstg LE AE T EIE az JT v a p_e 9 9 cn 8 1 n m SPLICE SPLICE AA as sj s 4 105 101 j 100 106 8 OOOO O 42 sio ca 48 46 6 48 49 4 49 20 alle es aa e 85 G8 27 G9 29 60 Gi 82 SPLICE 106 wc 3D c WHT PPL BLK BLK P WHT BLK WHT PPL WHT O amp z WHT RED Xx m SPLICE 105 T Q lt m WA m WHT BLK d A BCE FE B A CRANK COILS 1 d 20 With initial key ON 12 volt power is sent from the battery through the purple lead in the 10 pin harness to the pink lead at Engine Harness Pin C This is wake up power to the PCM The powers pin B4 which in turn pulls the MPR low The MPR powers the coils through Splice 105 and powers the engine for ignition PCM Pinout Cyl Number PCM Pinout Cyl Number PCM Pinout MGE EN ee T j 4 20 WIRING DIAGRAMS MerCruiser EFI 1003 555 Coil Harness Circuit Q RED E gt SE crn o pr d U 25 A UJ AU z U Pd D EF H SPLICE SPLICE BRN PNK U zt A BLK BLU z PNK Q PUR ea b BLK 77695 a Coil Harness To Engine Harness Connector b 1 And 8 Coil Connector c 3 And 6 Coil Connector d 5 And 4 Coil Connector e 7 And 2 Coil Connector
37. in the throttle body unit and the engines have the sensor located in the port fuel rail toward the rear of the engine Correcting the cause of the low fuel pressure will stop the horn A The ECM checksums listed below have these additional alarms turned ON in them NOTE Later production and service replacement ECMs have these extra alarms turned off If the ECM checksum is different from the ones listed below the extra alarms in that ECM is turned OFF MOM 4 3L EFI never had these extra alarms turned on 5 0L EFI With DO4B or 0074 checksum MOM 5 7L EFI With D7ED or D798 checksum 350 MPI 350 MPI Horizon 350 MPI Ski 350 MPI Inboard or 350 Horizon Inboard With E60D or EAED checksum MIE Black Scorpion With BB98 or BB42 checksum MOM 7 4L MPI or MIE 7 4L MPI Inboard With FE28 checksum MCM 454 MPI MCM 454 MPI Horizon or MIE 454 MPI Horizon Inboard With EBC4 check sum MCM 502 MPI or MIE 8 2L MPI Inboard With FO2D checksum MerCruiser EFI I 1003 SYSTEM COMPONENTS OPERATION 2 13 Additional MEFI 3 Features Moving Desired RPM Mode ECM s with Delphi 1623999 A Moving Desired RPM mode has been added to the MEFI 3 ECM This mode will increase the desired idle rpm to a calibrated set point according to the throttle position When the Throttle Position TP sensor is at the closed throttle setting the ECM will use Idle Air Control IAC and Ignition Cont
38. is not necessary Reads from absolute zero to 199 9 PSI 3 Can be used to apply slight pressure to test fuel systems for leaks 4 Must have a minimum of 100 milliamps draw but not more than 300 milliamps 5 Contains six tools for removal of terminal pins from harness blocks 6 7 8 9 1 Such as the Ferret 80 series from Stevens Instruments OTC and other suppliers Such as Snap On MT14GS15SV Used to listen to fuel injectors air leaks fuel pump s and IAC operation Used to check fuel pressure regulators for leakage and to attach vacuum gauge 0 Used to check the VST vent line for the presence of raw fuel Tool Manufacturers Cole Parmer Instrument Co Rinda Technologies Tools SPX Corporation Fluke Corp 800 323 4340 4563 N Elston Ave 655 Eisenhower Drive P O Box 9090 847 549 7600 Chicago IL 60630 Owatonna Minnesota 55060 Everett WA 98206 9090 847 247 2929 FAX 773 736 6633 800 533 0492 800 443 5853 847 549 1700 International FAX Fax 773 736 2950 Fax 800 283 5665 Kent More Tools SPX Corporation Stevens Instruments SPX Service Repair J tools 111 Greenwood Avenue 2300 Park Drive 29784 Little Mack Waukegan Illinois 60079 9375 Owatonna MN 55060 Roseville MI 48066 847 336 9375 800 344 4013 800 345 2233 Fax 847 662 6808 Fax 810 578 7375 3 2 DIAGNOSTICS MerCruiser EFI 1003 5 Marine Parts amp Accessories Attention Dealers You know from your own marine service experie
39. meet stringent emissions and fuel economy require ments One method of measuring the mass of the air flow into the engine is the Hot Wire system A small wire is stretched across the air intake An electrical charge is run through the wire causing it to heat up As air flows over the wire it changes the temperature of the wire which changes its resistance and the resulting current flow The ECM can pick up this change in current flow and calculate the amount of air entering the system 2 28 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 Another method of measuring the mass of the air flow into the engine is the vane type Mass Air Flow sensor A movable vane is mounted in protrudes into the air intake system The rush of intake air through the sensor causes the vane to be deflected The deflection is measured and a signal sent to the ECM NOTE The speed density system is more than accurate enough for our marine applications The additional reduction in emissions and the resulting increase in fuel economy with the Mass Air Flow system are negligible But when automotive manufacturers must meet emis sions standards they often have to take small improvements where they can find them Speed Density Operation MerCruiser EFI I The engine s RPM is easily determined from the REF HIGH signal on systems with EST igni tion or the timing signal from the Thunderbolt Distributor s hall effect sensor on small block MEFI 3 mode
40. rpm Basically a regular 350 Magnum MPI with enhancements to increase durability and extend service intervals Most service intervals are now 3 years instead of 1 year Platinum spark plugs and hi temperature spark plug wires Extensive use of EDP and ceramic coating Closed cooling standard with the new ex tended life antifreeze 5 years 1000 hours Constant tension hose clamps and engine mounted freshwater flushing device MEFI 3 GM 99 Software ECM MEFI 3 GM 99 software ECM s are introduced in this model year MEFI 3 ECM s are used on all big block models 0L086001 and above actually 1998 1 2 models and all small block models 0L340000 and above New codes and features are enabled Refer to Service Bulletins 99 2 and 99 3 Quicksilver DDT cartridge MerCruiser Version 2 0 90 803999 is required to allow scan ning of the MEFI 3 ECM See Service Bulletin 96 4 revised Rinda Software Update Rinda software update chip Version 3 4 Rinda 94056 is re quired to allow scanning of the MEFI 3 ECM See Service Bulletin 96 9 revised 350 Magnum MPI all models New 90 mm throttle body Service Notes Refer back to all previous service notes SB 99 2 Rev 7 99 MEFI 3 changes on small block V6 and V8 models Primarily the new ignition system addition of fuel pressure sensor and intake air temperature sensor now added to all models Includes MEFI 3 wiring diagrams SB 99 3 Rev 6 00 M
41. scan tool DTC Step 5 Are Any Trouble Codes Stored Chart Compare data values displayed on the scan tool to the typical scan tool data values page Trouble Are The Displayed Values Normal Or Close To The shooting Typical Values a Ignition ON engine OFF b Install CodeMate Tester and switch it to Normal Mode Chart Step 7 A 1 Observe the MIL Is the MIL ON Diag nostic Testing a Switch CodeMate Tester to Service Mode b Ignition ON engine OFF Step 9 it c Observe the MIL on the CodeMate Tester Does the MIL Flash DTC 12 a Switch CodeMate Tester to Normal Mode b Attempt to start the engine Did The Engine Start And Continue To Run a Ignition ON Engine OFF b Switch CodeMate Tester to Service Mode Are Any Additional DTC Stored Does A Customer Complaint Or Driveability Problem Symp ie d Currently Exist toms Aids Verify Check CKT 451 for a short to ground Repair e a With CodeMate Tester on normal mode 7 b Ignition ON engine OFF Step 12 Step 8 c Observe the MIL on the CodeMate Tester Does the MIL Flash DTC 12 3 58 DIAGNOSTICS MerCruiser EFI 1003 Diagnostic Trouble Codes MEFI 1 Codes ECT Engine Coolant Temperature TP Throttle Position Sensor IAT Intake Air Temperature IC Ignition Control KS Knock Sensor MEFI 2 Codes ECT Engine Coolant Temperature High Temperature Indicated ECT Engine Coolant Tempera
42. seconds No reference voltage Open circuit EST open GM ignore first 20 spark events requires 10 distributor only faults to set code Faulty ignition module Ignore first 20 spark events requires 10 Snort creuit faults to set code Faulty reference pickup i Incorrect base 43 Continuous Must have continuous knock retard for at timing knock least 30 seconds Faulty knock sensor Disconnected After 513 tdc knock free events rpm gt sensor No knock 3000 and MAP gt 70 and filtered sensor e hose Broken open circuit Faulty knock sensor 3 60 DIAGNOSTICS MerCruiser EFI 1003 3 Codes continued Code Connection Conditions Comments Number Open secondary wire Open primary cable Reserved Invalid ECM checksum Bad ECM Ignore first 20 spark events requires 8 Coil driver fault fo sel code Open circuit Faulty sensor Bad wrong regulator Short circuit Faulty sensor No fuel pump power Fuel pressure Minimum run time 10 sec high Sensor output high 4 9 volts Fuel pressure Minimum run time 10 Sec low Sensor output low 0 1 volts MerCruiser EFI 1003 DIAGNOSTICS 3 61 Injector Balance Test Multi Port Models Test Procedure STEP 1 STEP 2 STEP 3 3 62 DIAGNOSTICS The injector balance tester is a tool used to turn the injector ON for a precise amount of time thus spraying a measured amount of fuel into the manifold This causes a d
43. sensor open will read sensor Hi on scan tool NOTE VDC PWR Low if shorted or no voltage engine will not start if VDC PWR voltage falls velow 22 volts will set sensor faults Pitot CKT Lo Sea Pump PSI Lo Sea Pump CKT Hi Sea Pump CKT Lo Sea Water Temp Fuel Level 1 Ye Ye Ye Ye Ye Ye Ye Ye Ye Ye NA Onmeda NA T LES es es es es es es es No No es es es No No N A N A N A A A A A A NOTE 9 Shift Switch will activate code when engine rpm are above 3500 rpm and 40 load MerCruiser EFI I 1003 EFI SYSTEM COMPONENTS OPERATION 2 19 555 Warning System Operation continued Smartcraft Audio Available Fem Alam Powers Des Steer CKT Hi 100 Short or high voltage EE We EE CKT or TPS1 CKT or a er 100 Open or high voltage 5 VOC PWA Low Short or low engine may Open MAT Sensor Hi 2 Bp min 9096 h MAT Sensor Lo Yes 2Bp min 90 default to 32 degrees F Shift Switch 5 2 Bp min Open Circuit NOTE If any 5v sensor becomes shorted to ground the engine will not start If the engine is operating when the short occurs the engine may stop operating and will not start NOTE 1 GM EFI ignition system failure open or shorted driver will flag EST 1 fault NOTE 2 TPS must see 5 throttle then back to 0 to flag IAC fault NOTE 3 2 wire sensor open will read sensor Hi on scan tool NOTE
44. short or open 21 TPS voltage HIGH 21 TPS voltage HIGH 22 TPS voltage LOW 22 TPS voltage LOW 23 IAT HIGH or LOW open or short T voltage HIGH open IAT voltage HIGH open 25 voltage LOW short IAT voltage LOW short 33 MAP HIGH or LOW short or open 33 MAP voltage HIGH 33 MAP voltage HIGH 34 voltage LOW 34 voltage LOW 41 Open IC circuit 41 Open IC circuit 42 IC or bypass circuit 42 IC or bypass circuit 42 IC or bypass circuit 43 Knock circuit failure 43 Continuous knock detected 43 Continuous knock detected 44 Cannot detect knock activity 44 Cannot detect knock activity 45 Ignition coil driver circuit fault 51 Calibration checksum error 51 Calibration checksum error 51 Calibration checksum error 52 EEPROM failure in ECM 52 failure uel pressure sensor HIGH 62 Fuel pressure sensor LOW NOTE Not every engine will use every possible code check the service manual for the codes used on a specific engine Footnotes 1 Signal lead shorted to power 2 Signal lead shorted to ground or open 3 Circuit s either open or shorted to ground 4 C grounded and or Bypass open or grounded 6 Big block engines only with Delco EST ignition 7 Small block engines only with Thunderbolt distributor and coil 8 Reference 5V open or shorted to ground IMPORTANT On the L29 injector banks are 1 3 5 amp 7 and 2 4 6 amp 8 other models
45. sit idle long enough for phase separation to take place In addition internal corrosion may take place during storage if alcohol has washed protective oil films from internal components 6 2 GENERAL INFORMATION MerCruiser EFI 1003 Fuel Delivery System Boating standards NMMA etc and Coast Guard regulations must be adhered to when constructing the engine compartment GENERAL The main concern of a boat s fuel system is safety this must be achieved through a technically sound installation and constant inspection The fuel system from the filler pipe to the fuel pump is the same in principle for all boats The fuel tank is an integrated component of the boat Refer to the special information on service and mainte nance which you have received from the tank manufacturer Only a few points related to function and safety are listed here Refer to boating standards NMMA etc and Coast Guard regulations for complete guidelines e All connections should be on the upper side of the tank e The drain plug at the lowest point on the tank serves to permit the removal of water and sediment e The filler pipe outer diameter should be at least 2 in 50 mm e The tank breather pipe must have an inner diameter of at least 1 2 in 13 mm and must be fitted with a swan neck to prevent water from entering the tank It is recommended that the exact route and length of the fuel lines be established at the first inst
46. the gauge When using the Guard the maximum range that can be applied to this Guard installed on the Gauge is 30 in Hg to 15 psi 1 1 1 1 NOTE 2 The Gauge Guard Liquid has to be filled under a vacuum You have to pull a vacu um through the diaphragm seal with a vacuum pump and fill the Guard through fill port on the side Failure to do this will cause an incorrect gauge reading 3 20 DIAGNOSTICS MerCruiser EFI I 1003 Temp Probe Compression Fitting Reducer Bushing Schrader Valve Pipe Fitting T Fitting 1 4 1 4 1 1 2 Water Separating FuelFilter Temp Probe Compression Fitting Reducer Bushing Schrader Valve Pipe Fitting T Fitting 1 4 3 From Fue Supply Water Separating FuelFilter MerCruiser EFI 1003 DIAGNOSTICS 3 21 Delco EST Ignition Troubleshooting Erratic Spark Symptoms 1 6 If the erratic spark occurs only when the engine is warm is especially bad on warm days remove the ignition module and make sure that plenty of thermal transfer compound is present on the module s base The module will misfire if it is too hot Verify that the purple power lead carbureted or red power lead EFI to the ignition coil is holding steady battery voltage during the erratic spark misfiring event If not check the key switch and safety lanyard switch for loose connections or internal failure a Try isolating the bo
47. theory alone since the ECM doesn t really know how much air is flowing through the engine it is just assuming it knows how much based on the repeatability of airflow theory In reality the system is simple rugged and works extremely well But the ECM cannot compensate for changes in volumetric efficiency of the engine 1003 EFI SYSTEM COMPONENTS OPERATION 2 29 How Does The Get The Speed Density Data Input The engine speed sensor is already available to the ECM This information can come from the ignition distributor The density sensor will have to be created and added to the engine This sensor is called the Manifold Absolute Pressure Sensor or MAP sensor It can be thought of as an electric barometer A MAP sensor is different than a hand held vacuum gauge in that the vacuum gauge reads in inches of mercury below the current barometric pressure A MAP sensor reads in inches of mercury above absolute zero like a barometer so that it can cor rect for day to day variations of the barometric pressure An electrical signal will be sent from the MAP sensor to the ECM Near Perfect Vacuum 1 Atmosphere 14 7 psi 29 92 in Mercury 101 kPa Atmosheric Vent to Pressure atmosphere W Flexible Diaphragm w Hose Fitting Barometer Scaled in inches of Vacuum Gauge Mercury in Hg Measures a vacuum with respect to atmpsheric pressure also called gauge pressure Measures atmospheric pressure Figure1 M
48. under pressure FUEL COOLER D Engine cooling water is passed through the center of the fuel cooler The fuel flows through a separate passage that surrounds the outside of the water passage tube Fuel can exit the cooler at two loca tions The first is through a fuel line to the fuel rail i and the second is through the fuel pressure regu lator e Fuel that is sent to the engine passes from the fuel cooler to the fuel rail i through a fuel line FUEL RAIL I The fuel rail assembly is located on top of the intake manifold Some systems have a single rail and others use two rails A fuel rail positions the fuel injectors in the intake manifold and supplies fuel evenly to each injector j FUEL INJECTORS J The fuel injectors are eight electric solenoid operated devices that meter pressurized fuel to each engine cylinder The Fuel Injectors are controlled by the Electronic Control Module ECM which grounds the injector coil to open the injector nozzle and allow fuel to spray into the intake manifold next to the intake valve Fuel pressure to the injectors is controlled by the Fuel Pressure Regulator FUEL PRESSURE REGULATOR E The fuel pressure regulator is mounted to the top of the fuel cooler and is connected internally with the fuel passage that surrounds the fuel cooler water passage tube It is a diaphragm operated relief valve that maintains constant pressure differential across the injec tors at all times An i
49. wires together using splice clips and rosin core solder 73048 4 Cover splice with heat shrink sleeve to insulate from other wires 73048 GENERAL INFORMATION 6 11 Wiring Connector Service NOTES Most connectors in the engine compartment are protected against moisture and dirt that could create oxidation and deposits on the terminals This protection is important because of the very low voltage and current levels found in the electronic system The connectors have a lock which secures the male and female terminals together A secondary lock holds the seal and terminal into the connector When diagnosing open circuits are often difficult to locate by sight because oxidation or ter minal misalignment are hidden by the connectors Merely wiggling a connector on a sensor or in the wiring harness may locate the open circuit condition This should always be consid ered when an open circuit or failed sensor is indicated Intermittent problems may also be caused by oxidized or loose connections Before making a connector repair be certain of the type of connector Some connectors look similar but are serviced differently Replacement connectors and terminals are listed in the Parts Catalog Ensure that the connector seals are not deformed or crushed when mating the connectors together 6 12 GENERAL INFORMATION MerCruiser EFI 1003
50. 0 1 0 on 377 CID 6 2L 454 CID 7 4L and 502 CID 8 2L engines 5 Multi Engine Gasoline Installations It is best to use a fuel pickup and supply line for each engine If a single pickup and line is used line must not be smaller than 1 2 in 13mm 1 0 6 Larger diameter than previously specified lines and fittings must be used on installations requiring long lines or numerous fittings 7 Fuelline s should be installed free of stress and firmly secured to prevent vibration and or chafing MerCruiser EFI 1003 GENERAL INFORMATION 6 3 8 Sharp bends in fuel lines should be avoided 9 Aflexible fuel line must be used to connect fuel supply line to fuel inlet fitting on engine to absorb deflection when engine is running SPECIAL INFORMATION ABOUT ELECTRIC FUEL PUMPS ACAUTION The electric fuel pump and factory installed water separating fuel filter have been carefully designed to function properly together Do not install additional fuel filters and or water separating fuel filters be tween fuel tank and engine The installation of additional filters may cause e Fuel Vapor Locking e Difficult Warm Starting e Piston Detonation Due to Lean Fuel Mixture Poor Driveability SPECIAL INFORMATION FOR ALL GASOLINE ENGINES Avoid gasoline fire or explosion Gasoline is extremely flammable and highly explosive under certain conditions NEVER use gasoline as a cleaning solvent IMPORTANT The following
51. 0 Fuel Inlet 1 24 EFI PRODUCT HISTORY MerCruiser EFI 1003 24 Throttle Body Assembly Installation Components 5 Flame Arrestor 8 Adaptor Assembly TBI 9 Gasket 10 Gasket 12 MAP Sensor 13 Seal 16 Stud Kit 19 Connector 22 Shaft 24 Plate MerCruiser EFI 0804 EFI PRODUCT HISTORY 1 25 T 7 4L L29 MPI Induction System 1 Starboard Engine Cover 2 Port Engine Cover 3 Engine Cover Screws 4 4 Plenum 5 Plenum Screws 8 6 Plenum Gaskets 2 7 Adapter Studs 3 8 Adapter Gasket 9 Fuel Injector Harness 10 Fuel Rail Screws 11 Fuel Rail Stud 12 Fuel Rail 13 Fuel Injectors 8 14 O Ring 15 Fuel Rail Plug 16 Intake Manifold Screws 12 17 Manifold Absolute Pressure Sensor MAP NV 18 MAP Sensor Seal 19 Intake Manifold __ 20 Intake Manifold Gaskets 2 YI D 62 21 Vacuum Fitting Intake Manifold __ 22 Water By Pass Hose 23 Hose Clamps 2 24 Water By Pass Fitting 2 1 26 EFI PRODUCT HISTORY MerCruiser EFI 0804 16 496 8 1L MPI Induction System Typical a Intake Manifold b Fuel Rail c Throttle Body a Fuel Rail Assembly b Intake Manifold c Throttle Body MerCruiser EFI 0804 EFI PRODUCT HISTORY 1 27 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI 0804 Table of Contents Page Abbreviations 2 1 1 amp
52. 0 Mag Alpha Bravo 1 2 or 3 300 pshp 4600 5000 rpm 350 Mag Horizon Bravo 1 2 or 3 300 pshp 4600 5000 rpm MX 6 2 MPI Bravo 1 2 or 3 320 pshp 4800 5200 rpm MX 6 2 MPI Horizon Bravo 1 2 or 3 320 pshp 4800 5200 rpm 496 Mag Bravo 1 2 or 3 375 pshp 4400 4800 rpm 496 Mag HO Bravo 1X XR 2X 3X 425 pshp 4600 5000 rpm Inboards 350 Mag MPI Inboard 300 pshp 4400 4800 rpm 350 Mag Horizon Inboard 300 pshp 4400 4800 rpm MX 6 2 MPI Inboard 320 pshp 4600 5000 rpm MX 6 2 Horizon Inboard 320 pshp 4600 5000 rpm 8 1S Horizon Inboard 370 pshp 4200 4600 rpm 8 1S HO Inboard 420 pshp 4400 4800 rpm Tow Sports Inboards p 350 Mag Tow Sports Inboard 315 pshp 4600 5000 rpm gt MX 6 2 Tow Sports Inboard 320 pshp 4800 5200 rpm p Black Scorpion Tow Sports Inboard 330 pshp 4800 5200 rpm p MX 6 2 Black Scorpion Tow Sports Inboard 340 pshp 4800 5200 rpm Service Notes Black Scorpion and MX 6 2 Black Scorpion are new versions of these models They have been modified to use the ECM 555 System SB 2003 06 V6 and V8 GMEFI with No Start Engine Miss Fire or Engine Shut Off Condi tions 1 16 EFI PRODUCT HISTORY MerCruiser EFI 1003 11 2005 Model Year Model Line Summary from product line brochure Sterndrives gt 4 3 Alpha Bravo 2 or 3 220 pshp 4400 4800 rpm gt 5 0
53. 0 pshp 4800 5200 rpm MX 6 2 MPI Horizon Bravo 1 2 or 3 320 pshp 4800 5200 rpm 496 Mag Bravo 1 2 or 3 375 pshp 4400 4800 rpm 496 Mag HO Bravo 1X XZ XR 2X 3X 425 pshp 4600 5000 rpm Inboards p 350 Mag Inboard 300 pshp 4400 4800 rpm p 350 Mag MPI Horizon Inboard 300 pshp 4400 4800 rpm p MX 6 2 MPI Inboard 320 pshp 4600 5000 rpm p 6 2 MPI Horizon Inboard 320 pshp 4600 5000 rpm 8 15 Horizon Inboard 370 pshp 4200 4600 rpm 8 1S HO Inboard 420 pshp 4400 4800 rpm EFI PRODUCT HISTORY 1 15 Tow Sports Inboards p 350 Mag Tow Sports Inboard 315 pshp 4600 5000 rpm gt MX 6 2 Tow Sports Inboard 320 pshp 4800 5200 rpm p Black Scorpion Tow Sports Inboard 330 pshp 4800 5200 rpm p MX 6 2 Black Scorpion Tow Sports Inboard 340 pshp 4800 5200 rpm Service Notes V6 and Small Block V8 engines use 555 System Black Scorpion and MX 6 2 Black Scorpion engines use MEFI 3 System This was the last year of production for this version of EFI System SB 2002 2 Inline Fuel Filter Kit SB 2002 3 Required Boost Pump Installation SB 2002 12 New Minimum EFI and MPI Cranking Battery Requirements 2004 Model Year Model Line Summary from product line brochure Sterndrives 4 3 Alpha Bravo 2 or 3 220 pshp 4400 4800 rpm 5 0 MPI Alpha Bravo 1 2 or 3 260 pshp 4600 5000 rpm 35
54. 02 3 1 6 EFI PRODUCT HISTORY MerCruiser EFI 1003 7 If fuel odors are noticed in the oil cavity of the mechanical fuel supply pump used on VST models except 262 Magnum EFI models drain and refill the cavity SB 97 5 Multiple battery precautions with EFI models SB 97 20 Required fuel line replacement on Cool Fuel models This effects a massive number of 1997 and 1998 models The fuel lines may fail causing a high pressure fuel leak or may collapse internally causing low fuel pressure above approximately 2800 3500 rpm 1998 Model Year MerCruiser EFI I 1003 Model Line Summary from product line brochure 4 3 L EFI Alpha Bravo 2 or 3 210 pshp 4400 4800 rpm 5 0 L EFI Alpha Bravo 1 2 or 3 240 pshp 4400 4800 rpm The 1998 Product Hand book lists this engine at 230 pshp 5 7 L EFI Alpha Bravo 1 2 or 3 260 pshp 4400 4800 rpm 350 Magnum Alpha Bravo 1 2 3 or BlackHawk and Ski Inboard 300 pshp 4600 5000 rpm 350 Magnum standard Inboard 300 pshp 4400 4800 rpm Black Scorpion MPI Ski Inboard 315 pshp 4800 5200 rpm Scorpion 377 MPI Ski Inboard 360 pshp 4800 5200 rpm 7 4 L MPI Bravo 1 2 or 3 310 pshp 4200 4600 rpm 7 4 L MPI Inboard 310 pshp 4000 4400 rpm 454 Magnum MPI Bravo 1 2 3 or BlackHawk 385 pshp 4600 5000 rpm 454 Magnum Horizon Inboard 380 pshp 4400 4800 rpm 8 2 L MPI Inboard 400 pshp 4400 4800 rpm 502 Ma
55. 02 Magnum EFI MP multi port The Bravo 3 drive is now an option of these models A detuned version of the 454 Magnum EFI MP is offered as an inboard model It is called the 7 4L EFI MP multi port Bluewater Inboard Same EFI system as previous models This model may not have actually been released in 1995 The 350 Magnum EFI with the Alpha One drive is now called the 5 7L EFI Alpha One 2 new small block EFI models 350 Magnum EFI MP Bravo One 265 pshp 350 Magnum EFI MP Tournament Ski Inboard 280 pshp Both use a performance tuned tunnel ram intake manifold with individual runners This is a multi port system with the fuel injectors mounted in the lower intake manifold Same throttle body as the big block models Same VST system as the 1994 small block models Delco EST ignition Same shift cut out function as 1994 models GM MEFI 1 ECM Service Notes Refer back to all previous service notes All 1995 model year engines use MEFI 1 GM 93 software ECMs Twin engines can be connected together with the EFI Data Link Harness 84 805696A 2 This will allow you to scan both engines when connected to either en gine This cable will also make sure that if one engine goes into Power Reduction mode the other will also Do Not use an EFI engine on an original Alpha One or older MR R or MC 1 drive The high pressure low volume water pump is not compatible with an EFI engine s cooling system EFI engin
56. 03 DIAGNOSTICS 3 53 EFI Troubleshooting Guide Systems cont Visual Physical Check Il IV VI VII VIII 8 54 Verify that the battery is fully charged and is of sufficient capacity for the engine being tested If necessary substitute a known good battery Check the battery cable connections Make sure they are clean and tight If present discard wing nuts and replace with corrosion resistant hex nuts A corrosion resistant toothed washer should be installed between the battery terminal and the cable end stack up must be battery terminal wash er cable nut Make sure the cable connections are tight at the starter solenoid and that the block fuse on the starter solenoid if present is tight and its through bolt is not loose Also make sure the ground stud is not loose in the engine block and that its nut is tight If there is any doubt about the mechanical condition of the engine perform a compression test Make sure the safety lanyard is correctly installed and that the customer understands the correct starting procedure clear flood mode Check that all grounds are clean and tight If the negative battery cable is connected to the ground stud that does not contain all of the EFI and engine wiring harness ground leads consider moving the negative battery cable to that ground stud Check all vacuum lines for splits kinks and proper connections The fuel regulator on MPI models must be connected to manifo
57. 1 8 1 HOSDM P AB12345678 c Model Year MerCruiser EFI I 1003 EFI SYSTEM COMPONENTS OPERATION 2 15 ECM PCM 555 Engine Guardian Strategy amp Additional Guardian Sensors MerCruiser EFI I Engine Guardian is the focal point of the self diagnostic strategy of ECM PCM 555 It helps protect the engine from possible damage that could result from several faulty conditions The system monitors the sensors incorporated on the engine and if a malfunction is discovered a fault description is stored in the PCM and available power is normally reduced By ensuring engine output is at a low enough level the engine is better protected from thermally induced failures For example if an open or short is found in an exhaust manifold sensor available power will be reduced to 90 of total the warning horn will sound 2 beeps per minute and the MercMoni tor gauge SC1000 will display a warning lamp In an exhaust manifold overheat condition the maximum rpm will vary with the temperature of the manifold and could be limited to idle in extreme cases of overheating a continuous horn will sound and the SC1000 will display a warning lamp IMPORTANT Engine Guardian cannot guarantee that engine damage will not occur when adverse operating conditions are encountered Engine Guardian is designed to warn the operator of an adverse condition and to reduce power by limiting rpm in an attempt to reduce possible engine damage The boat operator is ultimately respon
58. 1 models only manually adjust remote control throttle lever to get 1200 engine rpm NOTE MEFI 2 and MEFI 3 models only ECM will automatically adjust engine rpm to approximately 1200 rpm when put in the service mode on a scan tool or when using the timing tool 5 Check ignition timing Specification is 8 degrees BTDC If incorrect rotate the distributor until timing is correct Torque clamping screw to 18 Ib ft 25 Nm Recheck ignition timing Disconnect scan tool or timing tool from DLC connector If required return remote control throttle lever to idle position and shut off engine Restart engine increase rpm to 1300 then return to idle position slowly Ensure that engine returns to idle rpm Readjust throttle cable if required 10 Shut engine off ECM PCM 555 System Models The ignition timing is not adjustable on these engines MerCruiser EFI 1003 MAINTENANCE OFF SEASON STORAGE 5 1 Cold Weather or Extended Storage Precautions BE CAREFUL while working on fuel system gasoline is extremely flammable and highly explosive under certain conditions Be sure that ignition key is OFF and do not smoke or allow sources of spark and or open flames in the area Avoid Fire or Explosion To prevent a potential fire hazard be sure that engine com partment is well ventilated and that there are no gasoline vapors present during start ing or fogging of engine Avoid Fire or Explosion Fuel injection sy
59. 2 ECM Input and Sensor Descriptions 2 2 ECM Input and Sensor Descriptions 2 3 555 Input and Sensor Descriptions 2 4 555 Input and Sensor Descriptions 2 5 GM E C M Identification 2 6 GM EFI ECM Comparison and Code Listing 2 7 Power Reduction Mode Lanyard Stop Circuit and Multiple Engine Information 2 8 Early MEFI 1 Master Slave Data Link Connector DLC and Safety Lanyard Switch Circuits 2 9 Later MEFI 1 and All MEFI 2 Master Slave and Data Link Connector DLC Circuits 10 MEFI 3 Master Slave and Data Link Connector DLC Circuits 2 11 GM EFI ECM Comparison and Code Listing 2 12 MEFI 3 and Audio Warning 2 13 Additional MEFI 3 ECM Features 2 14 Moving Desired RPM Mode ECM s with Delphi 1623999 2 14 Load Anticipation Mode 2 14 Shift Switch Operation 2 14 555 Identification 2 15 Typical ECM Calibration Label 2 15 Typical PCM Calibration Label 2 15 555 Engine Guardian Strategy amp Additional Guardian Sensors 2 17 ECM 555 Warning System Operation 2 18 Two Wire Sensors ECT and IAT 2 21 Three Wire Sensors MAP TP and FP 2 21 MerCruiser EFI System Electronic COMPONENS 2 cers dick e ema eges Fee REA 2 22 MEFI 3 MOM Sterndrive 7 4L MPI Bravo and MIE Inboard
60. 2 case Only 16210729 is true MEFI 2 3 1996 models are all VST 1997 was a transition year 1998 models are all Cool Fuel 4 Scorpion models use EST ignition all other small blocks use the Thunderbolt hybrid ignition Power Reduction Mode Lanyard Stop Circuit and Multiple Engine Information The engine control module ECM on all 1996 and newer model year EFI engines has the Power Reduction Mode disabled Because of this change it is important that 1995 and older models not be intermixed with 1996 and newer models on multiple engine boats It is important that all of the engines in a boat have either the power reduction mode enabled or disabled but not a combination of both The 3 pin Master Slave connector and the 2 pin Safety Lanyard Stop Circuit connector have been removed on some 1996 and newer MEFI 1 models and all MEFI 2 and MEFI 3 models On these newer models if the Master Slave functions are desired it is necessary to build a custom data link harness and connect it between the DLC connectors on the engines The serial data terminal Pin G orange or orange black lead on the data link connector DLC of both engines must be connected together and the master slave terminal Pin H yellow lead on the Slave engine s DLC must be grounded Data Link Harness Kit P N 84 805696A2 can be used to connect early MEFI 1 models equipped with a 3 pin master slave connector at the rear of the engine near the flywheel housing When eng
61. 6 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 Throttle Position TP Sensor Circuit NOTE MEFI circuit shown ECM PCM 555 circuits are similar 75788 a Throttle Body b Throttle Position TP Sensor 416 GRY J1 15 CIRCUIT DESCRIPTION The Throttle Position TP Sensor provides a voltage signal that changes as throttle blades open or close Signal voltage should vary from about 5 volts at idle to about 4 5 volts at Wide Open Throttle WOT The TP signal is one of the most important inputs used by the Electronic Control Module ECM for fuel control and for most of the ECM controlled outputs MerCruiser EFI I 1003 EFI SYSTEM COMPONENTS OPERATION 2 47 Intake Air Temperature IAT Sensor Circuit or Manifold Air Temperature MAT Sensor Circuit NOTE MEFI circuit shown ECM PCM 555 circuits are similar 1 Intake Manifold 2 AT Sensor N 75829 CIRCUIT DESCRIPTION The Intake Air Temperature IAT Sensor uses a thermistor to control the signal voltage to the The applies a voltage on CKT 472 to the sensor When the intake air is cold the sensor thermistor resistance is high therefore the ECM will see high signal voltage As the intake air warms the sensor resistance becomes less and the voltage drops At normal en gine operating temperature 160 180 F 71 82 C the voltage will measure about 1 5 to 2 0 volts 1 Sensor Temperature to Resistance
62. 7 4L Inboard 2 22 MerCruiser EFI System Electronic Components see previous page for component location see part numbers 2 23 The following sensors interact with the ECM Tv 2 24 The following are additional sensors used on the PCM 555 EFI System 2 25 There are different modes of engine operation 2 26 EFI System Air Delivery Components 2 27 Speed Density Theory and Operation 2 28 Speed Density Theory 2 28 Mass Air Flow Systems 2 28 Speed Density Operation 2 29 How Does The ECM Get The Speed Density Data Input dca cette eee E RETE Se 2 3 EST Ignition Source of Ref Hi Signal 2 32 EFI Engines with High Energy Ignition and Electronic Spark Timing EST 2 33 2 i EFI SYSTEM COMPONENTS OPERATION Page EST Operation Cranking Distributor Module Mode 2 34 EST Operation Engine Running ECM Control Mode 2 35 EFI Engines with Mercury Marine Thunderbolt V Distributor and MEFI 3 ECM 1999 V 6 and Small Block V 8 Engines 2 36 555 Ignition System 2 38 PCM 555 Ignition System 2 39 Manifold Absolute Pressure MAP Sensor CUCU cated 1 625 EE 2 42 Ignition Control IC Circuit Source of Ref Hi signal systems 2 43 EFI Engines with Mercury Marine Thunderbolt V Distributor and
63. 813 BLK THROTTLE POSTION 417 DK BLU THROTTLE POSITION SENSOR TP SENSOR SIGNAL 5 VOLTS REFERENCE FUEL PRES FUEL PRESSURE SURE 475 GRN SENSOR SIGNAL SENSOR FP MANIFOLD 416 GRY 5 VOLTS REFERENCE ABSOLUTE PRESSURE 432 LT GRN MAP SIGNAL MAP SENSOR eia BLK 814 BLK SENSOR GROUND ENGINE COOLANT 814 BLK TEMPERATURE ECT ENGINE COOLANT 410 YEL TEMPERATURE ECT SENSOR SIGNAL 496 DK BLU KNOCK SENSOR 1 114BLU OIL PRESSURE SWITCH KNOCK SENSOR 1 150 BLK Orz z 906 TAN WHT LUBE BOTTLE 150 BLK SHIFT SWITCH SHIFT INTERRUPT 207 PPL SIGNAL 76098 4 12 WIRING DIAGRAMS MerCruiser EFI 1003 Wiring Diagram MEFI 3 with Mercury Distributor V6 and Small Block V8 3 of 4 TO FUEL PUMP RELAY FUSE 440 0RN BATTERY 2 RED BAT FUSE 4400RN gt gt TO DLC DLC 15A CONNECTOR SYSTEM IGNITION RELAY TO E Euh TQ IGN INJ FUSE 902 RED 439 PNK IGNITION 150 3 PNK BLK TO INJECTORS AND 902 RED FUEL PUMP RELAY DISTRIBUTOR BLK ECM WHT GRN J WHT RED GROUND 450 BLK ECM GROUND BLK ECM GROUND 439 PNK 430 PPL WHT DIST REF 902 RED 121 WHT 121 WHT IGN COIL IGNITION COIL TEMP SENDER z 121 WHT Li 208 ww LOAD ANTICIPATION 585 TAN WHT TRANSMISSION m E OVERTEMP PNK AUDIO WARNING 29 DIE GRI CIRCUIT
64. AY TIP Early 454 502 Models 7 4L 454 c i L 29 Models SYSTEM COMPONENTS OPERATION MerCruiser EFI 1003 Fuel Injector Identification Revised Aug 6 2004 e and PCM 555 Engine Injector Identification Engine Color System Injector Model Code psi kPa P N Manufacture Comments V6 4 3L V8 5 7L 6 2L ECM 555 MPI Cool Fuel GM MPI intake GMEFI system V6 4 3L V8 Neutral 43 296 885176 GM 5 0L 350 Mag MX6 2 Models V8 5 7L 6 2L 555 MPI Cool Fuel MerCruiser 320 EFI style intake plenum injectors Black Scorpion White Tip 30 207 805225A 1 Keihin 5 7L amp 6 2L V8 8 1L PCM 555 MPI Cool Fuel GM intake plenum injectors V8 496 Mag Black Tip 43 296 881693 GM Delphi 8 1S Models Neutral Tip 43 296 881693 GM Delphi e MEFI 1 22 3 ECM Engine Injector Identification Engine Color System Injector Model Code psi kPa P N Manufacture Comments V8 5 7L MEFI 1 TBI VST Non Gen 350 Mag EFI Blue Black 12 82 None GM See SB 94 8 Ski V6 4 3L V8 5 0L 5 7L MEFI 1 TBI VST and Cool Fuel Non Gen and Gen engines All V6 EFI all Pink Purple 30 207 852956 GM V8 EFI models V8 5 7L MEFI 1 MPI VST Non Gen 350 Mag MPI Orange 43 296 806807 1 Keihin Bravo Ski V8 5 7L MEFI 1 MPI VST Gent 350 Mag MPI Orange 43 296 806807 1 Keihin Bravo V8 5 7L MEFI 1 MPI Cool Fuel on Starboard side
65. EFI 1003 GENERAL INFORMATION 6 9 Wiring Colors for MerCruiser NOTE Color codes listed below DO NOT apply to fuel injection system harnesses ABBREVIATIONS BLACK BLK BLK All All Grounds TUB Trim Trailer Switch Protected Fused Wires from Battery RED PURPLE RED PUR Protected 12V to Trim Panel Ignition Switch 12V YELLOW RED YEL RED M Switch to Starter Solenoid to Neutral Start TAN BLUE TAN BLU Audio Warning System Also Electric Chokes on models so equipped NOTE Yellow used as GROUND wire in Europe and by some North American builders NOTES 6 10 GENERAL INFORMATION MerCruiser EFI 1003 Wiring Harness Service Wire Repair MerCruiser EFI I 1003 Marine engine control circuits contain many special design features not found in standard land vehicle wiring Environmental protection is used extensively to protect electrical contacts and proper splicing methods must be used The proper operation of low amperage input output circuits depends upon good continuity be tween circuit connectors Before component replacement and or during normal troubleshoot ing procedures visually inspect any questionable mating connector Mating surfaces should be properly formed clean and likely to make proper contact Some typical causes of connec tor problems are listed below 1 Improperly formed contacts and or connector housing 2 Damaged con
66. EFI 3 changes to trouble codes and audio warning system opera tion all models Updated in December 1999 SB 99 4 Rev 5 00 Distributor sensor failures on small block V6 and V8 MEFI 3 models New sensor is black old sensor was gray SB 99 7 Rev 1 01 Gasoline engine vapor locking Tremendous amount of information on vapor lock its causes and remedies Also a list of tools to properly troubleshoot the fuel System 1 10 EFI PRODUCT HISTORY MerCruiser EFI 1003 SB 99 8 EFI MPI fuel pumps with low pressure Effects a large number of OL3XXXXX series engines Defective check valve in the Cool Fuel electric fuel pump causes fuel re striction above 4000 rpm Refer to bulletin for serial number groups and visual identifica tion of suspect pumps 2000 Model Year MerCruiser EFI I 1003 Model Line Summary from product line brochure 4 3 L EFI Alpha Bravo 2 or 3 210 pshp 4400 4800 rpm 5 0 L EFI Alpha Bravo 1 2 or 3 240 pshp 4400 4800 rpm 5 7 L EFI Alpha Bravo 1 2 or 3 260 pshp 4400 4800 rpm 350 Magnum Alpha Bravo 1 2 or 3 300 pshp 4600 5000 rpm 350 Magnum MPI Horizon Alpha Bravo 1 2 or 3 300 pshp 4600 5000 rpm 350 Magnum standard Inboard 300 pshp 4400 4800 rpm 350 Magnum Ski Inboard 315 pshp 4600 5000 rpm 350 Magnum MPI Horizon Inboard 300 pshp 4400 4800 rpm Black Scorpion MPI Ski Inboard 330 pshp 4800 5200 rpm 7 4 MPI Brav
67. EFI Fuel System Early 502 System with Old Style VST a Q Boat Fuel Water Separating Gen V Tank gt Fuel Filter gt Sea Fuel Pump Sight Vent Line Tube Fuel Fill to Intake to Throttle Body Prime In Tank Port Fuel Pressure Needle amp High v Reference Line Seat Assembly Imi Pressure Electric um Return gt Fuel Ful O Pump Pressure N no e a Vapor Regulator Assembly Fuel Pump Vapor Separating Tank l Fuel Pressure creen Fuel Pressure Service Tap Regulator Injector Filter One Piece Fuel Rail Assembely Filter oM gt J Fuel Pressure L _ E Regulator o z lt IE Reference Line to Typical Plenum ne ypica N Fuel Injector New Style VST Vapor Regulator Assembly Modified Sight Tube to Throttle Body Boat Fuel Water Separating Gen V Sight Tube to Tank Fuel Filter SealFuel Pump J gt Throttle Body Vent Line Fuel Fill to Intake In Tank PA s Needle amp High eat Assembly LE I Electric Return gt Fuel Kuri Pump Yapor Pressure T Vapor Regulator Assembly ee a Fuel Pump Vapor Separating Tank Pick up Fuel Pressure Fuel Pressure Service Tap Regulator Injector Filter One Piece Fuel Rail Assembely Filter Al J p Fuel Pressure 04 5 JT 72573 Fuel Inje
68. EFI System Harness 7 4L Multi Port Injection L29 MEFI 2 NOTE All BLACK wires with a ground symbol are interconnected within the EFI system harness 1 Fuel Pump 2 Distributor 3 Coil 4 Electronic Spark Control Module 5 Data Link Connector DLC 6 Manifold Absolute Pressure MAP Sensor 7 Knock Sensor Port and Starboard 8 Air Control IAC 9 Throttle Position TP Sensor 10 Engine Coolant Temperature ECT Sensor 11 Electronic Control Module ECM 12 Fuel Pump Relay MerCruiser EFI 1003 13 Ignition System Relay 14 Fuse 15 Amp Fuel Pump Fuse 15 Amp DLC Battery Fuse 10 Amp Injector Ignition Knock Module 15 Harness Connector To Starting Charging Harness 16 Positive Power Wire To Engine Circuit Breaker 17 Intake Air Temperature IAT Sensor 18 Gear Lube Bottle Audio Warning Switch 19 Oil Pressure Audio Warning Switch 20 Water Temperature Sender Gauge Sy 75682 WIRING DIAGRAMS 4 7 EFI System Harness 454 502 8 2L Models except L29 MEFI 3 NOTE All BLACK wires with a ground symbol are interconnected within the EFI system harness NOTE Component position and orientation shown is arranged for visual clarity and ease of circuit identification 1 Fuel Pump 2 Distributor 3 Coil 4 Knock Sensor KS Module 5 Data Link Connector DLC 6 Manifold Absolute Pressure MAP Sensor 7 A
69. Engines to treat gasoline Follow instructions on container 2 If boat is to be placed in storage with fuel containing alcohol in fuel tanks if fuel without alcohol is not available Fuel tanks should be drained as low as possible and Quicksilver Gasoline Stabilizer for Marine Engines added to any fuel remaining in the tank Refer to Fuel Requirements for additional information 3 Run engine sufficiently to bring it up to normal operating temperature and allow fuel with Quicksilver Gasoline Stabilizer to circulate through fuel system Shut off engine Change oil and oil filter Flush cooling system Refer to Flushing Cooling System procedure Remove and discard water separting fuel filter N Q Install new filter 75533 Water Separating Fuel Filter MerCruiser EFI 1003 MAINTENANCE OFF SEASON STORAGE 5 3 9 Prepare fogging mixture information MC Service Bulletin 2001 15 a Ina 6 US gal 23 L remote outboard fuel tank mix 5 US gal 19 L regular unleaded 87 octane 90 RON gasoline 64 fl oz 1 89 L Mercury or Quicksilver Premium Plus 2 Cycle TC W3 Outboard oil 5 fl oz 150 mL Mercury or Quicksilver Fuel System Treatment and Stabilizer OR1 fl oz 30 mL Mercury or Quicksilver Fuel System Treatment and StabilizerCon centrate 10 Disconnect and plug boat s fuel line from Water Separating Fuel Filter inlet 11 Connect remote outboard fuel tank with the f
70. FI Bravo One e 415 pshp 4600 5000 Peak torque 3600 3800 e Lingenfelter intake system increases torque output by over 100 ft lb at low speeds bronze water passage e Multi port fuel injection injectors are mounted in the lower intake manifold e MerCruiser designed and built throttle body high flow uses progressive secondary Two 60mm bores stainless steel shafts and ball bearings e VST vapor separator tank system eliminates return line to boat fuel tank High pressure electric pump in VST no fuel cooling but VST has pressure regulator intended to maintain positive pressure in VST to help prevent vapor lock This was the Old Style VST system e Uses similar mechanical supply pump as previous Gen V models e 65 amp alternator e Delco EST ignition e GM MEFI 1 ECM e Easy re power same engine mounts fuel line and harness hookups 1994 Model Year Model Line Summary from product line brochure p 454 Magnum EFI Stern Drive 385 pshp 4600 5000 rpm p 502 Magnum EFI Stern Drive 415 pshp 4600 5000 rpm p 454 Magnum EFI Tournament Ski Inboard 395 pshp 4600 5000 rpm Model Line Changes from Recertification book 502 Magnum EFI continues now offered with Bravo One or BlackHawk p Hole added to the secondary throttle plate to improve operation when equipped with BlackHawk drive p 0F128963 and above will use the new style VST e 2 new big block models 454 Magnum EFI Bravo O
71. Gent Black Scorpion Orange 43 296 806807 1 Keihin Ski 5 7L V8 5 7L 6 2L MEFI 1 3 MPI Cool Fuel on Port side Gen 350 Mag MPI White Tip 30 207 805225A 1 Keihin Bravo Inbrd Ski Black Scorpion Ski 5 7L amp 6 2L 377 Scorpion Bravo amp Ski 2 80 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI 0804 e MEFI 1 22 3 ECM Engine Injector Identification Contd Engine Color System Injector Model Code psi kPa P N Manufacture Comments V8 5 7L 6 2L MEFI 2 3 MPI Cool Fuel on Port side Gent 350 Mag MPI None 30 207 861260T Magneti Marelli Alpha Bravo Inbrd Ski and MX 6 2 MPI Bravo Inbrd V8 7 4L L29 MEFI 2 3 MPI Cool Fuel GM MPI intake plenum injectors 7 4L MPI Olive Green 43 296 802632 GM Bravo amp Inbrd Band on Tip V8 7 4L MEFI 1 GM TBI Cool Fuel GM TBI intake 7 4LX EFI Bravo Yellow Black 30 207 853998 GM 7 4L EFI Inbrd V8 7 4L 8 2L MEFI 1 MPI VST and Cool Fuel MerCruiser MPI intake All 7 4L amp 8 2L White Tip 36 248 805225A 1 Keihin MPI models V8 7 4L 8 2L MEFI 3 MPI Cool Fuel MerCruiser MPI intake All 7 4L amp 8 2L None 43 296 861260T Magneti Marelli All 7 4L amp 8 2L V8 8 2L MEFI 3 MPI Cool Fuel MerCruiser intake HP500 EFI Unknown 43 296 849896 1999 UP GM V8 8 2L MEFI 3 Dual TBI Cool Fuel Super Charger intake GM TBU HP575 SCi Yellow Black 30 207
72. M 555 MPI Gen 3 Cool Fuel GM MPI intake GMEFI system 5 0L MPI 350 Mag None 42 5 288 892681 Regulator in top of Gen 3 Cool Fuel Module MX6 2 Models V8 8 1L PCM 555 MPI Cool Fuel GM intake plenum injectors V8 496 Mag Blue Brown 43 296 861126 1 Regulator on fuel cooler Green ring on 8 1S Models hose fitting V8 8 1L PCM 555 MPI Gen 3 Cool Fuel GM intake plenum injectors V8 496 Mag None 42 5 288 892681 Regulator in top of Gen 3 Cool Fuel Module 8 1S Models e MEFI 1 2 3 ECM Fuel Regulator Identification Engine Color System Regulator Model Code psi kPa P N Comments V8 5 7L MEFI 1 TBI VST Non Gen engines GM TBU 350 Mag EFI Unknown 12 82 None Regulator in TBU See SB 94 8 Ski V6 4 3L V8 5 0L 5 7L MEFI 1 TBI VST Non Gen and Gen engines GM All V6 EFI all Unknown 30 207 852955 Regulator in TBU V8 EFI models V6 4 3L V8 5 0L 5 7L MEFI 1 3 TBI Cool Fuel engines GM TBU All V6 EFI all Unknown 30 207 852955 Regulator in TBU V8 EFI models V8 5 7L MEFI 1 MPI VST Non Gen engines Keihin injectors 350 Mag MPI Unknown 43 296 806808 2 Regulator on the fuel rail Bravo Ski V8 5 7L MEFI 1 MPI VST Gen engines injectors 350 Mag MPI Unknown 43 296 806808 2 Regulator on fuel rail Bravo V8 5 7L MEFI 1 MPI Cool Fuel on Starboard side Gen engines Keihin injectors Black Scorpion Unknown 43 296 808062 1 Regulator on fue
73. MEFI 1 143 19SINIOJN 5001 2 2 NOILIVH3dO SLN3NOdMWOO WALSAS 159 GM EFI COMPARISON and Code Listing MEFI 1 93 95 models MEFI 1 96 98 models 2 98 350 Mag amp 129 MEFI 3 99 amp newer models GM 93 software GM 93 1 software in a GM 96 software in a 2 case GM 98 or 99 software 2 case GM part 16210729 Largest ECM 93 95 Medium size ECM 96 98 Medium size ECM Smallest ECM square 4 short mounting bolts 4 long mounting bolts 4 long mounting bolts 3 short mounting bolts J1 J2 on opposing ends of case J1 J2 on opposing ends of case J1 J2 on opposing ends of case J1 J2 parallel to each other Same pin locations as MEFI 2 Same pin locations as MEFI 2 Same pin locations as MEFI 1 Unique pin assignments Power reduction mode active Power reduction is NOT active Power reduction is NOT active Power reduction is not active Must manually advance throttle Must manually advance throttle ECM automatically sets rpm ECM automatically sets rpm prior to base timing service mode prior to base timing service mode during base timing service mode during base timing service mode Delco EST Ignition Delco EST Ignition Delco EST Ignition EST Big Block T bolt Small Block Separate knock module SB 94 12 Separate knock module Separate knock module Integral knock module 2 channels Clear flood mode active even when Clear flood mode active even when Clear flood mode active even when Clear flood mod
74. MEFI 3 ECM 1999 V 6 and Small Block V 8 Engines 2 44 Additional ECM PCM 555 Sensors 2 45 Crank Position and Camshaft Position Circuits 2 45 Engine Coolant Temperature ECT Sensor Circuit 2 46 Throttle Position TP Sensor Circuit 2 47 Intake Air Temperature IAT Sensor Circuit or Manifold Air Temperature MAT Sensor Circuit 2 48 Knock Sensor KS Circuit MEFI Systems 2 49 PCM 555 Port And Starboard Knock Sensor i sa 2 es tn oR usa ncn 2 50 Fuel Pressure FP Circuit Small Blocks and V6 s with MEFI 3 only 2 51 Additional PCM 555 Sensors 2 52 Exhaust Manifold Coolant Temperature EMCT Sensors 2 52 Sea Pump Pressure Sensor 2 53 1 and 2 Discrete Switch Inputs and MEFI 1 Shift Interrupt Circuit 2 54 2 Shift Interrupt Circuit 2 55 3 Shift Interrupt Circuit and Discrete Switch Inputs 2 56 555 Gear Indicator Shift Interrupt 2 57 Idle Air Control IAC Valve Operation MEFI Systems 2 58 Idle Air Control IAC Systems 2 59 PCM 555 System Idle Air Control IAC Valve Operation 2 60 Early 502 System with VST Fuel Delivery Components 2 62 Fuel Pressure Regulator Assembly 2 64 Co
75. MPI Alpha Bravo 1 2 or 3 260 pshp 4600 5000 rpm gt 350 Mag Alpha Bravo 1 2 or 3 300 pshp 4600 5000 rpm gt 350 Mag Horizon Bravo 1 2 or 3 300 pshp 4600 5000 rpm gt MX 6 2 Bravo 1 2 or 3 320 pshp 4800 5200 rpm gt MX 6 2 Horizon Bravo 1 2 or 3 320 pshp 4800 5200 rpm gt 496 Mag Bravo 1 2 or 3 375 pshp 4400 4800 rpm gt 496 Mag HO Bravo 1X XR 2X 3X 425 pshp 4600 5000 rpm Inboards gt 350 Mag Inboard 300 pshp 4400 4800 rpm gt 350 Mag Horizon Inboard 300 pshp 4400 4800 rpm gt MX 6 2 Inboard 320 pshp 4600 5000 rpm gt MX 6 2 Horizon Inboard 320 pshp 4600 5000 rpm gt 8 1S Horizon Inboard 370 pshp 4200 4600 rpm gt 8 1S HO Inboard 420 pshp 4400 4800 rpm Tow Sports Inboards gt 350 Mag Tow Sports Inboard 315 pshp 4600 5000 rpm gt MX 6 2 Tow Sports Inboard 320 pshp 4800 5200 rpm gt Black Scorpion Tow Sports Inboard 330 pshp 4800 5200 rpm gt MX 6 2 Black Scorpion Tow Sports Inboard 340 pshp 4800 5200 rpm Service Notes e EFI Cool Fuel 111 system introduced Single integrated module filter lift pump high pressure pump pressure regulator and cooler all in one unit Module mounted on right starboard side of engine opposite side of engine from location of Cool Fuel II system It is positioned above and forward of the starboard front engine mount fo
76. OMPONENTS OPERATION 2 49 555 Port And Starboard Knock Sensor Circuits NOTE ECM 555 System is similar with one Knock Sensor B A 9 6 6 6 d d 18 19 20 21 9 40 17 42 43 14 45 46 12 13 14 19 19 47 I I I I T x l m BLK RED Uem em BI K YEL D K ORA A Z O A KNOCK lt b Sensor Sensor 77685 a Port Knock Sensors b Starboard Knock Sensors The knock sensors detect engine detonation or spark knock and send a voltage signal to the PCM They are located on the lower half of the engine on both the port and starboard sides As the sensor detects knock the voltage output level increases and signals the PCM of the problem An unacceptable knock sensor reading will set a fault of Knock Sensor HI or Knock Sensor LO A normal reading is 83 000 104 000 at idle Readings indicating an open will fall in the 7 900 12 000 range and readings indicating a short will range from 3 800 5 100 2 50 EFl SYSTEM COMPONENTS OPERATION MerCruiser EFI 1003 Fuel Pressure FP Circuit Small Blocks and V6 s with MEFI 3 only 1 Intake Manifold 2 Fuel Rail 3 Fuel Pressure Sensor 75829 416 GRY 475 GRN 813 BLK MerCruiser EFI I 1003 EFI SYSTEM COMPONENTS OPERATION 2 51 Additional PCM 555 Sensors Exhaust Manifold Coolant Temperature EMCT Sensors The exhaust manifold coolant te
77. Pa 131 kPa Amount 19 psi 21 psi 17 psi 19 psi 19 psi 19 psi 19 psi 19 psi of Drop 131 kPa 145 kPa 117 kPa 131 kPa 131 kPa 131 kPa 131 kPa 131 kPa RE MerCruiser EFI 1 1003 DIAGNOSTICS 3 63 ECM Connector and EFI Symptoms Chart Big Block V8 other MEFI s Similiar NOTE Refer to appropriate Service Manual for specific applications The following chart will aid in diagnosis of symptoms These voltages were derived from a known good engine The voltages shown were done with the electrical system intact and op erational These are voltage requirements to operate the different circuits Do not attempt to obtain these voltages probing wires and connectors Serious damage could result in loss of engine operation or wiring damage Voltages can vary with battery conditions J 1 J 1 Connector 2 J lt gt n lt gt 4 2 Connector Shaded Area Denotes Pin Connector Location Used On Terminal 3 64 DIAGNOSTICS MerCruiser EFI I 1003 ECM Connector and Symptom Chart Big Block V8 J 1 Circuits In the following J 1 and J 2 Circuit Symptom Charts only those pins which are used by the are shown Pin numbers not listed are not used The Symbol indicates a system voltage battery IMPORTANT The following conditions must be met before testing 1 Engine at operatin
78. S OPERATION MerCruiser EFI 0804 System Module Features e Dual Pump Configuration Improved Vapor Lock resistance compared to engines equipped with current boost pumps e Corrosion Protection Strontium coated Internal water passage same as outboards External housing e coated e Engine Installation Low profile water connection disconnect as required during engine installation 3 8 thread inlet fuel connection e Service Access Modules located above front engine mount brackets in all applications e Water Jacketed Parallel water flow through module permits smaller module e Pumps immersed in fuel and draw from bottom of cavity Vapor rises to top of cavity pumps always draw liquid Reduced pump noise not audible over engine at idle e No external lines between filter boost pump pressure pump and regulator Eliminates 20 external fuel connectors e 5 seals not counting inlet and outlet Filter cap Modified SAE o ring seal Module Cover Controlled Crush quad ring Pressure Regulator Diametric o ring Pressure Relief Valve Diametric o ring Harness Fuel tight pass through fitting e Self Draining Drains when seawater pump outlet is drained MerCruiser EFI 0804 EFI SYSTEM COMPONENTS OPERATION 2 85 System Overview ws w w r Heat Exchanger Fuel pressure housing casting
79. ST Fuel Delivery Components The mechanical fuel pump c draws fuel from the boat s fuel tank a and through the water separating fuel filter b this filter is easily serviced with a spin on cartridge The mechanical fuel pump will supply fuel to the Vapor Separator Tank VAPOR SEPARATOR TANK D This is a fuel reservoir mounted on the top of the engine to the rear of the intake manifold Fuel is pumped into this tank to supply the EFI system Electric Fuel Pump e which is mounted inside the VST tank Fuel level is controlled by a float and needle and seat assembly f When the ignition switch is turned to the run position the ECM will turn on the fuel pump relay for 2 seconds When the ignition switch is turned to the crank position the ECM turns the fuel pump relay on causing the fuel pump to run If the ECM does not receive ignition ref erence pulses engine cranking or running it shuts off the fuel pump relay stopping the fuel pump When the relay is activated the Electric Fuel Pump draws fuel form the tank through a filter g mounted at the pump base Fuel is then sent out of the tank outlet line under pres sure and is routed into the Fuel Rail through high pressure lines FUEL RAIL ASSEMBLY 1 Fuel then enters the Fuel Rail Assembly which is located on top of the intake manifold The Fuel Rail positions the fuel injectors in the intake manifold and supplies fuel evenly to each injector FUEL INJECTORS J The fuel
80. STEM COMPONENTS OPERATION 74871R2 g Water flow through cooler h Vacuum line to intake manifold i Fuel rail Fuel injectors 8 k dummy regulator some MEFI 1 amp 2 models MerCruiser EFI 1003 350 Magnum Multi Port Injection with MEFI 1 and 2 350 Mag MPI Shown Scorpion Is Similar a Vacuum Line To Intake Manifold Base b Fuel Pressure Regulator Fuel Cooler Electric Fuel Pump Water Separating Fuel Filter Fuel From Tank Direction Of Water Flow Fuel Line To Fuel Rail Excess Fuel Return To Water Separating Fuel Filter Fuel Injectors 8 Fuel Rail Taso O O MerCruiser EFI I 1003 EFI SYSTEM COMPONENTS OPERATION 2 75 350 Magnum Multi Port Injection with 350 Mag MPI Shown Scorpion Is Similar a Vacuum Line To Intake Manifold Base b Fuel Pressure Regulator Fuel Cooler Electric Fuel Pump Water Separating Fuel Filter Fuel From Tank g Direction Of Water Flow h Fuel Line To Fuel Rail i Excess Fuel Return To Water Separating Fuel Filter Fuel Injectors 8 k Fuel Rail O O O 2 76 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 Throttle Body Injection With Cool Fuel System MerCruiser EFI I 1003 Fuel line from boat s fuel tank b Water separating fuel filter Electric fuel pump Fuel cooler Fuel pressure regulator Return line to fuel filter Water flo
81. T 29 DK GRN TE CONNECTOR HALVES TAN BLU BLU TAN D TO TRANSMISSION TEMP SWITCH TO AUDIO WARNING HORN YEL BLK TO TRANSMISSION 760998 2 56 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 555 Gear Indicator Shift Interrupt a Gear Indicator b Gear Indicator Switch Closed in Neutral Open in Gear Normally Closed Switch c Shift Interrupt Switch MerCruiser EFI 1003 o o tc x r d Shift Interrupt Switch Alpha Models Ato C Normally Closed Ato Open When Activated Ato B 10K Released Ato B co When Activated BtoC Always 10K Q e Jumper Plug Bravo Models f ECM 555 EFI SYSTEM COMPONENTS OPERATION 2 57 Idle Air Control IAC Valve Operation Systems The purpose of the IAC valve assembly is to control engine idle speed while preventing stalls due to changes in engine load The IAC valve mounted in the throttle body controls bypass air around the throttle valves 72800 1 Valve Air Flow Diagram a IAC Valve b EFI Throttle Body c Air Flow By moving a conical valve known as a pintle IN toward the seat to decrease air flow or OUT away from the seat to increase air flow a controlled amount of air moves around the throttle valve If rpm is too low more air is bypassed around the throttle valve to increase it If rpm is too high less air is bypassed around the throttle valve to decrease it Th
82. TION 2 53 1 and 2 Discrete Switch Inputs and MEFI 1 Shift Interrupt Circuit 450 BLK WHT 450 BLK WHT IC MODULE SHIFT CUTOUT SWITCH MEFI 1 ONLY BRAVO REQUIRES JUMPER PLUG 423 WHT 423 WHT 430 PUR WHT 424 TAN BLK 453 BLK RED 121 BRN 3 PNK NOT USED IGNITION COIL 112 DK GRN 31 TAN 3 PNK 931 BRN 931 BRN HARNESS CONNECTOR TOO IGNITION RELAY 121 WHT 2 54 EFI SYSTEM COMPONENTS OPERATION ECM GROUND ECM GROUND ECM IGNITION CONTROL DISTRIBUTOR REFERENCE HIGH BYPASS DISTRIBUTOR REFERENCE LOW DISCRETE SWITCH INPUTS OUT TO BUZZER COOLANT OVERHEAT OUT TO BUZZER AUDIO WARNING SYSTEM SWITCHES INPUT FROM AUDIO WARNING SYSTEM SWITCHES MerCruiser EFI I 1003 2 Shift Interrupt Circuit ECM SHIFT CUTOUT SWITCH MEFI 2 ONLY BRAVO REQUIRES JUMPER PLUG 923 WHT SHIFT INTERRUPT 150 BLK 75602R MerCruiser EFI I 1003 EFI SYSTEM COMPONENTS OPERATION 2 55 3 Shift Interrupt Circuit and Discrete Switch Inputs ECM 5 OIL PRESSURE _ 114 BLU J2 7 SWITCH 150 BLK O z 906 TAN WHT J2 24 LUBE BOTTLE 150 BLK SHIFT SWITCH E SHIFT INTERRUPT 207 PPL J2 9 SIGNAL ES TO SYSTEM TACH LEAD RELAY FROM COIL NEG TERMINAL TEMP SENDER 121 WHT 208 J2 20 LOAD ANTICIPATION TAN WHT 2 TRANSMISSION i i OVERTEMP AUDIO WARNING 41 26 CIRCUI
83. Table of Contents Page MerCruiser EFI Engine History and Major Changes 1 1 1993 Model Year 1 1 1994 Model Year 1 1 1995 Model Year 1 2 1996 Model Year 1 3 1997 Model Year 1 6 1998 Model Year 1 7 1999 Model Year 1 9 2000 Model Year 1 11 2001 Model Year 1 12 2002 Model Year 1 14 2003 Model Year 1 15 2004 Model Year 1 16 2005 Model Year 1 17 14i EFI PRODUCT HISTORY Page Multi Port Fuel Injection System Fuel Flow 1 19 Early 350 Mag MPI Induction System 1 20 350 MPI Magnum Gen Tournament Ski Black Scorpion Induction System 1 21 Later Model 350 Mag MPI Induction System Model 1 amp 2 Similiar 1 22 Later Model 350 Mag MPI Throttle Body Assembly 1 23 Throttle Body Assembly TBI EFI Models 1 24 7 4L L29 MPI Induction System 1 26 496 8 1L MPI Induction System Typical 1 27 Small Block V 8 Induction System V 6 SIMMAN usss u EA ER BESTE 1 27 MerCruiser EFI 0804 MerCruiser EFI Engine History and Major Changes 1993 Model Year Introduction of the first MerCruiser standard production EFI engine 502 Magnum E
84. The specification is 2 in Hg 7 kPa maximum at idle 3000 rpm full throttle and then back at idle rpm check at each point Any anti siphon valve or restriction that causes a higher reading can contribute to vapor lock ing and other driveability problems In hot weather if you see 0 vacuum on the gauge and the engine is still running poorly check the inlet fuel line to ensure that a good solid flow of fuel is in the line instead of a mixture of fuel and vapors If the vacuum is too high try a less restric tive anti siphon valve Restrictive anti siphon valves can cause vapor locking conditions Going to the next larger Inside Diameter fuel lines and fittings can help lower the vacuum also This larger diameter ID can also help correct vapor locking conditions An example is shown below 5 16 in 8 mm Fuel Line ID 5 5 in Hg or 17 8 kPa Too high 3 8 in 9 5 mm Fuel Line ID 2 5 in Hg or 8 2 kPa Too high 1 2 in 12 5 mm Fuel Line ID 0 8 in Hg or 2 7 kPa Good See MerCruiser Service Bulletin 99 7 Rev 1 01 for information on gasoline engine vapor locking 3 18 DIAGNOSTICS MerCruiser EFI I 1003 Equipment Used to Test Fuel RVP Fuel Temperature or Fuel System Vacuum Information from MerCruiser Service Bulletin 99 7 Testing Fuel RVP SPX OTC sells a test kit Gasoline Quality Testing Kit P N 7670 Testing Fuel Temperature or Vacuum Fittings required to make connections between engine fuel inlet and the b
85. U INJECTOR DRIVER 10 AMP 439 PN INJECTORS 1 4 6 7 481 468 GRN 41 17 DRIVER i 47 From 439 2 RED gt sr 465 DK GRN WHT A J1 23 PUMP RELAY 339 PNK E FUEL PUMP RELAY FUSE 15A FUEL PUMP RELAY FUEL PUMP E 441 BLU WHT IAC COIL A HIGH IDLE AIR CONTROL 442 BLU BLK IACCOIL A LOW IAC VALVE z 443 GRN WHT IAC COIL B HIGH 444 GRN BLK IAC COIL B LOW 461 ORN 916 YEL 150 BLK DLC CONNECTOR 450 BLK 1 FROM DIAGNOSTIC E USE 451 BLK WHT TERMINAL 15A L 440 ORN 419 BRN WHT 76079 MerCruiser EFI 1003 WIRING DIAGRAMS 4 15 Wiring Diagram 3 Big Block V8 2 of 4 ECM INTAKE AIR TEMPERATURE IAT SENSOR SIGNAL 813 BLK INTAKE AIR 472 TEMPERATURE IAT is 813 NEM SENSOR GROUND THROTTLE POSTION SENSOR TP THROTTLE POSITION SENSOR SIGNAL 417 DK BLU 5 VOLTS ee REFERENCE MANIFOLD 416 GRY 5 VOLTS REFERENCE PRESSURE 432 LT GRN MAP SIGNAL MAP SENSOR 814 BLK ENGINE COOLANT 9 814 BLK TEMPERATURE ECT 410 YEL SENSOR GROUND ENGINE COOLANT TEMPERATURE ECT SENSOR SIGNAL 76080 4 16 WIRING DIAGRAMS MerCruiser EFI 1003 Wiring Diagram 3 Big Block V8 of 4 TO FUEL PUMP RELAY E C M FUSE 440 ORN BATTERY FEED 2 RED ECM BAT FUSE 4400RN
86. Values Approximate 185 450 1 800 3 400 7 500 13 500 25 000 100 700 2 48 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 Knock Sensor KS Circuit Systems a Knock Sensor b Harness Connector c Knock Sensor KS Module INJ ECM TO SYSTEM FUSE 15A RELAY 439 PNK KNOCK SENSOR MODULE 486 PUR _ 496 DK BLU 496 DK BLU E KNOCK SENSOR UNES CIRCUIT DESCRIPTION MEFI 1 and MEFI 2 Engine detonation or spark knock is sensed with a module that sends a voltage signal to the ECM As the knock sensor detects engine knock the voltage from the KS module to the ECM drops and this signals the to start retarding timing The will retard timing when knock is detected and rpm and engine coolant temperature are above a certain value MEFI 3 Engine detonation or spark knock is detected with a sensor that sends a voltage signal to the As the knock sensor detects engine knock the voltage output level increases and this signals the to start retarding timing The will retard timing when knock is detected and rpm and engine coolant temperature are above a certain value NOTE MEFI 3 products do not have a knock module The sensor connects directly to the ECM as shown in diagram below ECM 496 DK BLU KNOCK SENSOR 1 MARNE SENSOR 2 L29 ONLY 7 KNOCK SENSOR 1 J KNOCK SENSOR 2 L29 ONLY MerCruiser EFI I 1003 EFI SYSTEM C
87. acer sleeve is being used If not upgrade the components SB 93 2 VST and recall on 502 EFI 0F013999 and below VST problem with sticking floats causing fouling of 48 spark plug ECM re calibration to prevent audio warn ing horn from causing idle control problems SB 93 25 454 Magnum EFI specifications SB 93 26 VST external fuel filter recall replacement with solid line affects all 454 and 502 EFI models with old style VST 0F128962 and below for 502 models and 0F130438 and below for 454 models SB 93 27 recall re calibration False 43 knock self test deactivated Affects 502 EFI with 0F137295 and below 1995 Model Year Model Line Summary from product line brochure 5 7L EFI Alpha Bravo 1 2 or 3 250 pshp 4400 4800 rpm 350 Magnum EFI MP Bravo 1 or 3 265 pshp 4600 5000 rpm 350 Magnum EFI Tournament Ski Inboard 265 pshp 4400 4800 rpm 350 Magnum Tournament Ski Inboard 280 pshp 4600 5000 rpm 7 4L EFI MP Bluewater Inboard 350 pshp 4000 4400 rpm 454 Magnum EFI MP Bravo 1 or 3 385 pshp 4600 5000 rpm 454 Magnum EFI MP Tournament Ski Inboard 395 pshp 4600 5000 rpm 502 Magnum EFI MP Bravo 1 3 or BlackHawk 415 pshp 4600 5000 rpm 1 2 EFI PRODUCT HISTORY MerCruiser EFI 1003 3 Model Line Changes from ReCertification book 454 and 502 Magnum EFI models continue but are now called 454 Magnum EFI MP and 5
88. adequate secondary spark If an air gap tester is used make sure it will not ignite any fuel vapors that may be present in the bilge A KV meter can also be used to check for adequate secondary voltage Make sure the secondary wires are in good physical shape correctly routed and that the boots are not split at either end Remove the distributor cap and check for signs of moisture and carbon tracking A If there is no spark and the engine is equipped with Delco EST ignition unplug the 4 pin connector at the distributor and recheck spark If spark is still not present the fault is isolated in the EST ignition system and is not an EFI system fault With the 4 pin connector disconnected this ignition can be diagnosed in the same manner as the 3 0 liter carbureted engine B f there is no spark and the engine is equipped with the Mercury Marine Thunderbolt distributor refer to Service Bulletin 99 2 for troubleshooting procedures These engines do not have a separate ignition module instead they use the 3 ECM to control the ignition coil primary circuit DIAGNOSTICS MerCruiser EFI 1003 EFI Troubleshooting Guide Systems cont Xl Check for adequate fuel pressure at the throttle body or fuel rail A If there is no fuel pressure check that the fuel pump is actually operating The pump must run for at least 2 seconds each time the key is turned to the on position If the fuel pump and the warning horn are not operat
89. all of the retainer bracket inside surfaces where it contacts the cooler and the fuel pump when installed a Retainer Bracket b Thermal Grease Exploded View Component List 1 Bracket 14 Fuel Cooler 2 Cover Base 15 Fuel Pump Wiring Harness 3 Screw and Washer 2 16 Retainer Bracket 4 Fuel Pressure Regulator 17 Nut 2 5 Return Fuel Line 18 Electric Fuel Pump 6 Retaining Ring 19 Inlet Fitting 7 O Rings 2 20 Fuel Line Inlet 8 Fuel Line to Fuel Rail 21 Cover 9 Gasket 22 Filter 10 Drain Plug 23 Seawater Hoses Hose Clamps 11 Stepped Screw Not Shown 12 O Rings 4 24 Vacuum Hose 13 Elbow 2 72 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 Cool Fuel System Water Separating Fuel Filter with Insulating Container MCM Model Shown Top Cover Some Models b Insulator Plate c Fuel Return Line from Regulator d Brass Fitting e Fuel Line to Fuel Pump f Brass Fitting 9 h i j k 5 Fuel Filter Mounting Bracket Nut Fuel Inlet Fitting Plug Water Separating Fuel Filter Bottom Cover Some Models MerCruiser EFI I 1003 EFI SYSTEM COMPONENTS OPERATION 2 73 Cool Fuel Systems Diagrams Multi Port Injection With Cool Fuel System a Fuel line from boat s fuel tank b Water separating fuel filter c Electric fuel pump d Fuel cooler e Fuel pressure regulator f Return line to fuel filter 2 74 EFI SY
90. allation of the engine to prevent problems later in connecting them to the engine All fuel lines must be well secured The holes where the lines run through the bulkheads should be carefully rounded off or protected with rubber grommets This prevents damage to the lines from abrasion The following but not limited to the following additional fuel connection related points applying to all engines unless otherwise stated must be considered Refer to boating standards NMMA ABYC etc and Coast Guard regulations for complete guidelines 1 On Gasoline Engines Fuel tank should be mounted below carburetor level if possible or gravity feed may cause carburetor fuel inlet needle to unseat and flooding may result 2 Fuel pickup should be at least 1 in 25 mm from the bottom of fuel tank to prevent picking up impurities 3 On Gasoline Engines The maximum measured vacuum at the engine s fuel inlet must not exceed 2 in Hg or 1 psi 6 9 kPa at 600 3000 full throttle rpm and idle rpm IMPORTANT Vacuum reading higher than specified can cause vapor locking with some of today s fuels It can also cause poor engine performance because of fuel starvation 4 On Gasoline Engines Fuel lines used must be Coast Guard approved USCG Type A1 Diameter of fittings and lines must not be smaller than 5 16 in 8 mm ID on 262 CID 4 3L and 305 CID 5 0L and 350 CID 5 7L engines Diameter of fittings and lines must not be smaller than 3 8 in 1
91. and injector pulse width There are three types of memory storage within the ECM ROM RAM and EEPROM Read Only Memory ROM is the permanent memory inside the ECM The ROM contains the overall control programs and once programmed cannot be changed The control program is the list of instruction the ECM will follow in performing its routines The ROM memory is non erasable and does not need power to be retained Random Access Memory RAM is the microprocessor scratch pad The processor can write into or read from this memory as needed The ECM uses RAM to store temporary values and data like coolant temperature or manifold pressure signals This memory is erasable and needs a constant supply of voltage to be retained Electronic erasable Programmable Read Only Memory EEPROM is the portion of the that contains the different engine calibration information that is specific to each marine application Information like fuel curve spark advance and default values are stored in EEPROM This type of memory will retain information until erased for insertion of new information Changing EEPROM memory requires special equipment and is usually not performed at the dealership without factory assistance The ECM supplies 5 or 12 volts to power various sensors or switches This is done through resistance in the ECM which is so high in value that a test light will not light when connected to the circuit Care should be taken to use a 10 meg ohm
92. and diagnostic a mms a Harness Connector Jumper Wire b Connector to Port Engine c Connector to Starboard Engine 71757 MerCruiser EFI I 1003 EFI SYSTEM COMPONENTS OPERATION 2 9 Later MEFI 1 and All MEFI 2 Master Slave and Data Link Connector DLC Circuits TO ECM BAT FUSE x m tc o 440 ORN DATA LINK CONNECTOR 461 ORN BLK 916 YEL BLK 450 BLK WHT 1 451 WHT BLK ECM SERIAL DATA MASTER SLAVE DIAGNOSTIC TEST TERMINAL MALFUNCTION INDICATOR LIGHT 75600R The 3 pin Master Slave connector and the 2 pin Safety Lanyard Stop Circuit connector have been removed on some 1996 and newer 1 models and all MEFI 2 and models 2 10 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI 1003 3 Master Slave and Data Link Connector DLC Circuits SERIAL DATA 916 YEL MASTER SLAVE 150 BLK DLC CONNECTOR 450 BLK 451 BLK WHT PNEU TEST L IL 440 ORN 419 BRN WHT INDICATOR 76097R MerCruiser EFI I 1003 EFI SYSTEM COMPONENTS OPERATION 2 11 NOILVH3dO S LN3NOdIWOO WALSAS Ids 2 143 19SIIOJEN 5001 1 GM 93 Software MEFI 2 GM 96 Software 14 ECT voltage HIGH open 14 ECT HIGH or LOW open or short 14 ECT voltage HIGH open 15 ECT voltage LOW short 15 ECT voltage LOW short 21 TPS HIGH or LOW
93. anifoid Absolute Pressure Barometric Pressure Gauge Pressure Atmospheric Pressure Intake Manifold Vacuum z Manifold Absolute Pressure 2 30 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 VACUUM GAUGE VS MAP SENSOR 115 L 90 w L 43 T 85 _ 25 80 24 ES wea qM L2 E ETEN e ERS z3 9 4 18 5 _ S pea 55 16 o 8 i 2 50 15 lt 2 F ug 20 2238 a amp 45 13 2 Le 24 12 8 fe lt 14 30 9 L8 L4 L 25 L E e 20 LL 6 5 WA EA 0 10 3 CONTE LLLLLLI F a 0 LO 0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 Hand Held Vacuum Gauge in Hg This graph is correct at Sea Level only MerCruiser EFI 1003 SYSTEM COMPONENTS OPERATION 2 31 EST Ignition Source of Ref Hi Signal The Electronic Fuel Injection EFI is controlled by an Electronic Control Module ECM This module is the nerve decision center of the system It uses all the information it gathers to manage ignition spark delivering increased fuel economy and maximum engine performance The EFI system uses inputs from sensors to make decisions on the amount of spark advance or retard allowed The EFI system has been designed to control ignition adva
94. armer Digital PSIG Gage Stevens Instruments Gearcase Pressure Tester Fuel quality testing kit Fluke Pressure Vacuum Transducer Module Electrical System Tools DMT 2004 multi meter Set 10 Mega ohm impedance Clamp on ammeter probe for any standard DVOM DVA adaptor for any standard DVOM EFI 12v test light unpowered IAC noid light EFI test lead set GM style harness test leads Packard connector repair Kit Quicksilver Electrical Hardware Kit bullet connectors Quicksilver Crimping Pliers packard style Quicksilver Harness Seal Kit Snap on Terminal Tool Kit Remote Starter Switch Rinda 94016 Ignition System Tools Kilo Volt meter Snap On Air gap spark tester single 1 2 inch gap Air gap spark tester 8 adjustable gaps Timing jumper plug jumps A amp B at DLC Continuity light 1 5v self powered Timing light MerCruiser EFI 0804 91 881833A2 91 803135 8 4814 8 4914 8 4614 91 806901 91 18078 91 805918A2 J 34730A2 OTC 7188 J 34730 400 OTC 7187 J37088 A J 41769 OTC 7660 J 37088 1A or J 41769 1 J 41769 2 See current MPP Acessories Guide for selection of tanks Model No 68920 10 5 34 J 39383A OT C 7670 PV 350 Fluke 91 892647A01 91 802650 91 89045 1 J 34142 B OTC 30535 Rinda 94025 J 35616 A J 38125 B 86 813937A2 91 808696 91 881814A1 TT 600 91 52024A1 MT2700 DIS KV 91 63998A1 91 850439T 1 91 805747A2 J 21008 A Locally available DIAGNOSTICS 3 1
95. asher e Fuel Line 75708 There are 2 ways of identifying each regulator by looking at them By a colored paint mark on its mounting flange and by a small ring that is on the regulator s hose fitting ALL TBI ENGINES AND SMALL BLOCK MPI ENGINES Black Scorpion with Cool Fuel module on starboard side has a 43 PSI fuel system 30 psi 207 kPa Paint Mark Pink Ring on Regulator s Hose Fitting None ALL 7 4L MPI L29 ENGINES AND ALL 454 502 MAG EFI MPI ENGINES WITH MEFI 3 ECM S AND ECM PCM 555 ENGINES 43 psi 296 kPa Paint Mark Blue Ring on Regulator s Hose Fitting Green ALL 454 502 MAG MPI ENGINES WITH MEFI 1 ECM S 36 psi 248 kPa Paint Mark Yellow and Orange Ring on Regulator s Hose Fitting Black MerCruiser EFI I 1003 EFI SYSTEM COMPONENTS OPERATION 2 65 Fuel Pressure Regulator Identification Revised Aug 6 2004 e and PCM 555 Fuel Regulator Identification Engine Color System Regulator Model Code psi kPa P N Comments V6 4 3L V8 5 7L 6 2L 555 MPI Cool Fuel GM MPI intake GMEFI system V6 4 3L V8 Blue Brown 43 296 861126 1 Regulator on fuel cooler Green ring on 5 0L 350 Mag hose fitting MX6 2 Models V8 5 7L 6 21 555 MPI Cool Fuel MerCruiser 320 EFI style intake plenum injectors Black Scorpion Pink 30 207 807952 1 Regulator on fuel cooler No ring on 5 7L amp 6 2L hose fitting 377 Scorpion Bravo amp Ski V8 5 0L 5 7L 6 2L EC
96. at harness with a shop test harness the 3 foot MerCruiser harness part 84 812475A3 and MerCruiser ignition switch assembly part 54212A7 If the problem disappears the problem is in the boat harness not the MerCruiser engine harness b There are several splices in the purple lead on almost all MerCruiser engines so it may be necessary to go into the engine harness to find the loose connection On an EFI engine ignition coil power comes from the system relay If the purple or red power lead to the coil holds steady voltage carefully flex the pink and brown harness between the coil and the ignition module while the engine is running If the engine runs better or quits replace the harness between the coil and ignition module This is usually because the filter in the pink lead has failed If erratic spark is still present isolate the gray carbureted or white EFI tach lead at the negative side of the ignition coil Use a suitable jumper lead to jump the purple or red lead to the ignition coil and leave the tach lead disconnected Kent Moore Jumper Lead Kit J 35616 works well or you can cut the gray or white tach lead near the ignition coil and install a bullet connector from Quicksilver connector kit part 86 813937A2 If the en gine now runs better tach lead is partially shorted to ground in the engine harness boat harness or in the tach itself Alpha EFI MEFI 1 Models if erratic spark is still present bypass s
97. ay fail causing a high pressure fuel leak or may collapse internally causing low fuel pressure above approximately 2800 3500 rpm 1999 Model Year Model Line Summary from product line brochure MerCruiser EFI I 1003 4 3 L EFI Alpha Bravo 2 or 3 210 pshp 4400 4800 rpm 5 0 L EFI Alpha Bravo 1 2 or 3 240 pshp 4400 4800 rpm 5 7 L EFI Alpha Bravo 1 2 or 3 260 pshp 4400 4800 rpm 350 Magnum Alpha Bravo 1 2 or 3 300 pshp 4600 5000 rpm 350 Magnum Ski Inboard 315 pshp 4600 5000 rpm 350 Magnum standard Inboard 300 pshp 4400 4800 rpm 350 Magnum MPI Horizon Inboard 300 pshp 4400 4800 rpm Black Scorpion MPI Ski Inboard 330 pshp 4800 5200 rpm EFI PRODUCT HISTORY 149 7 4 L MPI Bravo 1 2 or 3 310 pshp 4200 4600 rpm 7 4 L MPI Inboard 310 pshp 4000 4400 rpm 454 Magnum Bravo 1 2 or 385 pshp 4600 5000 rpm 454 Magnum Horizon Inboard 380 pshp 4400 4800 rpm 8 2 L MPI Inboard 400 pshp 4400 4800 rpm 502 Magnum Bravo 1 2 or 3 415 pshp 4600 5000 rpm Model Line Changes from ReCertification book Scorpion 377 MPI This is now considered a High Performance product and is marketed by Mercury Racing BlackHawk drive dropped for 1999 350 Magnum MPI Ski Inboard now rated at 315 pshp at 4600 5000 rpm New small block model 350 Magnum Horizon Inboard 300 pshp 4400 4800
98. ch is used as an engine speed reference rpm and as a timing reference The ECM completely controls ignition timing at all engine speeds This is similar to an EST ignition running in the ECM Control Mode The ignition coil driver transistor which was built into the EST ignition module is now inside the MEFI 3 42 32 IGNITION TO INJECTORS AND FUEL PUMP RELAY ECM GROUND ECM GROUND ECM GROUND ECM DIST REF 902 RED IGN COIL IGNITION COIL 2 44 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 Additional ECM PCM 555 Sensors The sensors described on the following pages are peculiar to the triple nickel operating sys tems ECM PCM 555 s do not display numeric Diagnostic Trouble Codes as do the MEFI A failure associated with any triple nickel sensor will turn on the number 4 LED on the DDT Crank Position and Camshaft Position Circuits The cam position sensor is not used on the 555 equipped engines PCM 555 Shown a Female Hex Fastener b Camshaft Position Sensor CMP c O Ring RS 76709 Engines with ECM555 s have their crank position sensors CPS located on the front of the engine This sensor sends the RPM signal to the ECM PCM 555 Shown a Crankshaft Position Sensor CPS 76720 The crankshaft position sensor located at the rear of the engine and the camshaft position sensor located at the front of the eng
99. condary terminal to ground b Remove one of the ignition module mounting screws and loosen the other Rotate the module out from the distributor frame then retighten the loose screw Connect the positive lead from a 1 5 volt AA or similar battery to the ignition module s P terminal pickup coil terminal c With the key in the ON position note the voltmeter reading It must be battery voltage If not you didn t verify the coil primary windings are good or you didn t find the short to ground in the gray tach lead If the voltage is OK proceed d While observing the voltmeter momentarily connect the negative lead of the 1 5 volt battery to the distributor frame The voltage must drop several volts as the module grounds the negative side of the coil If not replace the ignition module e When the negative battery lead is disconnected from the distributor frame the voltage must rise back to battery voltage and the ignition coil should fire If the voltage changes but the coil does not fire replace the ignition coil the secondary windings are open or shorted f When finished reconnect all leads and connectors DIAGNOSTICS 3 23 3 with Mercury Marine Distributor Ignition System Troubleshooting 3 24 DIAGNOSTICS Check that GRY tachometer lead is not shorted to ground at the tachometer or within the harness Is battery good Is distributor clamping screw tight Check all terminal connections at dis
100. ctor NI MerCruiser EFI 1003 C Regulator 1 a Reference Line to Plenum EFI SYSTEM COMPONENTS OPERATION 2 63 Fuel Pressure Regulator Assembly The pressure regulator is a diaphragm operated relief valve with fuel pump pressure on one side and regulator spring pressure and intake manifold vacuum on the other The regulator s function is to maintain a constant pressure differential across the injectors at all times The pressure regulator compensates for engine load by increasing fuel pressure as engine vacu um drops If the pressure is too hi or low poor performance can result Fuel Rail Spring Pressure To Return SS a Passage In Fuel Rail Vacuum Line To Intake Manifold Diaphragm 2 64 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 Cool Fuel System Fuel Pressure Regulators There are 3 different Cool Fuel fuel pressure regulators that are used in production If the wrong regulator is used on an engine that engine can have a problem with its fuel supply to the injectors When checking regulator pressure on MPI engines always remove the small black hose that goes to the regulator before the test This hose goes to the intake manifold or plenum and it has vacuum on it which causes the pressure to read lower at idle RPM By removing the hose the regulator s true pressure will be shown a Filter b Fuel Cooler Orifice c Pressure Regulator d Screw and W
101. d MASTER SLAVE SERIAL DATA BLK 450 BLK WHT 1 DIAGNOSTIC TEST 451 WHT BLK TERMINAL 461 ORN BLK 916 YEL MALFUNCTION 440 ORN INDICATOR LIGHT DATA LINK CONNECTOR 4 10 WIRING DIAGRAMS MerCruiser EFI I 1003 ECM Wiring Diagram V6 and Small Block V8 1 of 4 INJECTORS ONE IF EFI FOUR IF MPI INJECTORS 2 3 5 8 IF FOUR From INJ ECM FUSE 467 DK BLU INJECTOR DRIVER 10 AMP 439 PN INJECTORS ONE IF EFI FOUR IF MPI INJECTORS 1 4 6 7 IF FOUR 468 DK GRN 41 17 DRIVER From 439 2 RED nu 465 DK GRN WH J1 23 J1 23 RB FUEL PUMP RELAY 339 PNK FUEL PLIMP RELAY FUSE 15A FUEL PUMP RELAY FUEL PUMP 150 120 GRY 441 BRN OR BLU WHT IAC COIL A HIGH IDLE AIR ar CONTROL 442 RED OR BLU BLK IAC COIL 4 LOW IAC VALVE 443 YEL OR GRN WHT LAC COWL B HIGH 444 GRN BLK LAC B LOW 461 ORN SERIAL DATA 916 YEL MASTER SLAVE 150 BLK DLC CONNECTOR 450 BLK FROM 451 BLK WHT DIAGNOSTIC TEST FUSE TERMINAL 15A MALFUNCTION INDICATOR LAMP L 440 ORN 419 BRN WHT 76097 MerCruiser EFI 1003 WIRING DIAGRAMS 4 11 ECM Wiring Diagram V6 and Small Block V8 2 of 4 TEMPERATURE IAT T 472 TAN INTAKE AIR TEMPERATURE ATURE AT Mb IAT SENSOR SIGNAL 813 BLK NEM SENSOR GROUND
102. d as 1997 1 2 models Alpha models changed from a roller type shift cut out switch to the sealed plunger style switch All 1997 small block V6 and V8 models now use the Cool Fuel System The Black Scorpion now uses the standard Cool Fuel System modular style mounted on the port side of the engine A new ECM is required because the fuel pressure regulator is now 30 psi All 1997 1 2 big block models will use the Cool Fuel System All Cool Fuel models will use a serpentine belt Service Notes Refer back to all previous service notes All 1997 models use the 2 GM 96 ECM case but are loaded with MEFI 1 GM 93 software MEFI 2 cases can be identified as having long mounting bolts instead of the short bolts used on MEFI 1 cases Power reduction mode has been disabled on all 1996 and newer models If itis a MEFI 2 case it does not have power reduction regardless of the software loaded inside If any 5 7 liter EFI model has a surging problem Replace the spark plugs All Alpha One EFI MPI models use a shift cutout switch that opens the IC ignition control circuit between the ECM and the Ignition Module in the EST distributor If a carbureted normally open switch is installed the ECM will not be able to control ignition timing and the engine will run only on the timing programmed into the EST module Code 41 will eventually be triggered EFI models must use a shift cutout switch that is normally closed pn 87 8067
103. dings CF 10 F 20 F 30 40 50 F 60 F 8 5v 8 7v 8 9v 9 1v 9 3v 9 4v 9 5v 6 8 GENERAL INFORMATION MerCruiser EFI 1003 Charging Guide 12 Volt Battery Recommended Rate and Time for Fully Discharged Condition Twenty Hour 5 10 20 30 40 50 Rating Amperes Amperes Amperes Amperes Amperes Amperes 50 Ampere Hours or 10 Hours 5 Hours ats 2 Hours pes ours Above 50 to 75 7 1 2 3 1 2 2 1 2 1 1 2 Above 75 to 100 59 Hours 10 Hours 5 Hours 3Hours 21 2 2 Hours Ampere Hours Hours Above 100 to 150 30 Hours 15 Hours Buc 5 Hours Vaid 3 Hours Ampere Hours Above 150 20 Hours 10 Hours 61 2 5 Hours 4 Hours Ampere Hours Hours Initial rate for constant voltage taper rate charger To avoid damage charging rate must be reduced or temporarily halted if 1 Electrolyte temperature exceeds 125 F 52 C 2 Violent gassing or spewing of electrolyte occurs Battery is fully charged when over a two hour period at a low charging rate in amperes all cells are gassing freely and no change in specific gravity occurs For the most satisfactory charging the lower charging rates in amperes are recommended Full charge specific gravity is 1 260 1 280 corrected for temperature with electrolyte level at split ring Battery Power as Affected by Temperature 80 F 27 C 100 32 F 0 C 0 F 18 C 20 F 29 C 74310 Power Watts Available Power Watts Required MerCruiser
104. dule h CPS Signal 2 38 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 555 Ignition System MerCruiser EFI I The distributorless ignitions system DIS is designed to replace the mechanical distributor system in controlling the ignition secondary voltage It has no moving parts and does not re quire timing adjustments All ignition coils are designed to be run with the secondary loaded However this is particularly true with DIS The high voltage produced by these systems can cause personal injury and or equipment damage Coil design saturation time and primary current flow on distributorless systems are modified to produce more available energy If maximum current is attained the well time is shortened to reduce the wattage consumed by the system If minimum current is not attained dwell time is increased to allow full saturation of the ignition coil If current limiting occurs prior to dis charge dwell is decreased for the next sequence A sensing device is used to determine the crankshaft and camshaft position Hall Effect sen sors are used on the 496 cid 8 1l engine to synchronize and fire the coils at the proper time A Hall Effect sensor has a magnetic field introduced perpendicular to a current flowing through a solid conductor causing a measurable voltage This is why the voltage readings on these two sensors fluctuate within a range generating a square wave with the same patters as on the interrupter vanes on t
105. e ECM moves the IAC valve in small steps called counts These can be measured by scan tool test equipment which plugs into the DLC During idle the proper position of the IAC valve is based on engine rpm If the rpm drops below specification and the throttle valve is closed the ECM senses a near stall condition and calcu lates a new valve position to prevent stalling e Engine idle speed is a function of total air flow into the engine based on IAC valve pintle position throttle valve stop screws and PCV e Controlled idle speed is programmed into the ECM which determines the correct IAC valve pintle position to maintain the desired idle speed for all engine operating conditions and loads 2 58 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 e The minimum idle air rate is set the factory with stop screws This setting allows enough air flow by the throttle valves to cause the IAC valve pintle to be positioned a calibrated number of steps counts from the seat during controlled idle operation e If the IAC valve is disconnected and reconnected with the engine running the idle speed may be wrong In this case the IAC valve can be reset by doing the following turn off engine wait ten seconds and restart engine Idle Air Control IAC Systems 441 BRN OR BLU WHT J2 28 J1 28 IDLE AIR 442 RED OR BLU BLK J2 13 J1 12 El 444 LT GRN BLK J2 29 11 27 CIRCUIT DESCRIPTION The contr
106. e Malfunction Indicator Lamp MIL or store a DTC DO NOT use the Diagnostic Trouble Code DTC tables for intermittent problems The fault must be present to locate the problem Most intermittent problems are caused by faulty electrical connections or wiring Perform careful visual physical check Check for the following conditions e Poor mating of the connector halves or a terminal not fully seated in the connector body backed out or loose e Improperly formed or damaged terminals and or connectors All connector terminals in the problem circuit should be carefully checked for proper contact tension e Poor terminal to wire connection crimping This requires removing the terminal from the connector body to check Refer to Wiring Harness Service in the Description and Sys tem Operation section The vessel may be driven with a Digital Multimeter connected to a suspected circuit An abnormal voltage when malfunction occurs is a good indication that there is a fault in the cir cuit being monitored A scan tool see Special Tools for part numbers can be used to help detect intermittent conditions The scan tools have several features that can be used to locate an intermittent condition The following features can be used in finding an intermittent fault The Record feature or choosing not to erase data can be triggered to capture and store engine parameters within the scan tool when the malfunction occurs This stored informat
107. e Rinda MerCruiser scan tool SB 96 15 Required ECM replacement This effects 7 4 LX MPI Bravo models 0F602086 0K021173 and 7 4L Bluewater Inboard models 0F622498 0K144653 Calibration problem in the audio warning circuit EFI PRODUCT HISTORY 1 5 1997 Model Year Model Line Summary from product line brochure 262 Magnum EFI Gen Alpha Bravo 2 or 3 205 pshp 4400 4800 rpm 5 7 L EFI Alpha Bravo 1 2 or 3 220 pshp 4200 4600 rpm 5 7LX EFI Alpha Bravo 1 2 or 3 250 pshp 4400 4800 rpm 5 7 LX EFI Gen Bravo 1 2 or 3 280 pshp 4400 4800 rpm 5 7 LX EFI Gen Inboard 290 pshp 4400 4800 rpm 350 Magnum EFI Gen Alpha 280 pshp 4400 4800 rpm 350 Magnum EFI Gen Ski Inboard 290 pshp 4400 4800 rpm 350 Magnum MPI Gen Bravo 1 2 or BlackHawk 300 pshp 4600 5000 rpm Black Scorpion MPI Gen Inboard 315 pshp 4600 5000 rpm 7 4 LX EFI Bravo 1 2 or 3 300 pshp 4200 4600 rpm 7 4LX Bravo 1 2 or 3 330 pshp 4200 4600 rpm 7 4L Inboard 340 pshp 4000 4400 rpm 454 Magnum MPI Bravo 1 2 or BlackHawk 385 pshp 4600 5000 rpm 454 Magnum MPI Ski Inboard 395 pshp 4600 5000 rpm 8 2 L MPI Inboard 400 pshp 4400 4800 rpm 502 Magnum Bravo 1 2 or BlackHawk 415 pshp 4600 5000 rpm VVVVVVVVVVVVVVVY Model Line Changes from ReCertification book This model year was again a transition year some models were introduce
108. e is only active when the engine is not being cranked the engine is not being cranked the engine is not being cranked the engine is being cranked Shift interrupt switch opens the Shift interrupt switch opens the Shift interrupt switch opens ECM Shift interrupt switch opens ECM white IC line no spark white IC line no spark J1 19 retards timing closes IAC 2 9 retards timing closes IAC VST fuel system VST or Cool Fuel System Cool Fuel System Cool Fuel System IAT added on TBI units MPI Cool Fuel models require Fuel rail buffering required Staggered injector firing eliminates fuel rail buffering need for fuel rail buffering 7 possible codes 7 possible codes 15 possible codes 23 possible codes Technician must differentiate Technician must differentiate Technician must differentiate Scan tool DDT differentiates between active amp logged codes between active amp logged codes between active amp logged codes between active amp logged codes MEFI 3 Advanced Features Warning system Low oil pressure high water temperature and low drive oil level general warning 1 or high transmission temperature general warning 2 cause a continuous horn on all models However certain ECM s will sound the horn in one of two modes soft alarm 1 second on 3 seconds off below 3000 rpm and a hard alarm constant horn above 3000 rpm when an Active code is detec
109. e is opened when its ground is completed through a driver in the PCM To achieve different stages of IAC valve opening the PCM modulates the ground If the PCM wanted the valve to be half open it would ground the circuit 5096 of the time If it wants the valve fully open it would ground the circuit 100 of the time PWM is defined as the percent age of time on versus the percentage of time off and is infinitely variable A failure in the IAC valve or its circuit will set a fault 77487 a Valve b Hose Connection C Hex Bolts 2 60 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 555 IAC CIRCUIT NOTE 555 IAC Circuit is similar C B A gt 8 7 YD 3 G 6 5 6 S 7 40 4 10 12 13 15 46 9 10151233 415 16 1213 14 15 16 17 18 19 20 21 1748 19 20 21 22 23 24 17 48 19 20 21 22 3 24 22 23 24 25 26 27 28 29 30 31 32 BLK DK GRN SPLICE 105 77677 IAC Sensor Connector b 12 Volt Transducer Power From MPR c 12 Volt Transducer Ground The idle air control IAC valve is a 12 volt circuit powered by the Main Power Relay MPR It is located at the top rear of the engine The normal resistance value for the IAC at 21 degrees C 70 degrees F is 10 1 ohms A malfunction of the IAC will set a fault of IAC Output MerCruiser EFI I 1003 EFI SYSTEM COMPONENTS OPERATION 2 61 Early 502 System with V
110. e the filter assembly from the Cool Fuel Module at this time 7T Allow any fuel that may be in the filter assembly to drain out through the bottom of the filter assembly and into the Cool Fuel Module filter reservoir 8 Remove the filter cup from the filter cap by grasping the filter cap and rotating it in a clockwise direction while holding the filter cup stationary 9 Remove the used water separating fuel filter element from the filter cup place it in a 3 84 DIAGNOSTICS clean approved container MerCruiser EFI 0804 Electrical 10 Dispose of any water or debris that may be in the filter cup 11 Install a new water separating fuel filter element into the filter cup Push the element into the cup until completely seated Inspect O ring in cap and replace if necessary 12 Attach the filter cap to the filter cup by grasping the filter cap and rotating it in a counter clockwise direction while holding the filter cup stationary until filter cap locks securely into place 13 Install the fuel filter assembly slowly into the Cool Fuel Module to prevent spilling fuel and align the screws retained in the filter cap with the screw holes in the Cool Fuel Module Tighten the filter assembly retaining screws until hand tight 14 Torque each filter assembly retaining screw Rm p FWerssembymmmngsme 48 4 15 Reconnect the Cool Fuel Module harness to the engine wiring harness 16 Supply cooling water
111. ence rpm and as a timing reference The ECM completely controls ignition timing at all engine speeds This is similar to an EST ignition running in the ECM Control Mode The ignition coil driver transistor which was built into the EST ignition module is now inside the MEFI 3 42 32 IGNITION TO INJECTORS AND FUEL PUMP RELAY ECM GROUND ECM GROUND ECM GROUND ECM DIST REF 902 RED IGN COIL IGNITION COIL 2 36 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 555 Ignition System The fires the ignition system by sending a signal to the coil driver on the rear of the engine The coil driver controls the high current flow through the primary windings of the smart coil On the 555 series there is one coil driver and one ignition coil controlled by the The high voltage spark from the smart coil is sent to a High Voltage Switch HVS that distributes the spark to the appropriate cylinder just like a regular distributor How ever the HVS does not time the spark it only distributes the spark A crankshaft position sen sor CPS is used to tell the crankshaft position and rpm The doesn t know where the cylinder number 1 is it only knows the position of a cylinder The spark plug leads con nected to the HVS must be routed to the appropriate spark plug or the wrong cylinder will spark just like in any conventional distributor ignition Howeve
112. engine to obtain reading 6 Fuel pressure should be within specifications 7 9 psi If not replace fuel pump NOTE ff the screen on the inlet side of the boost pump is clogged the boost pump pressure will be low 77645 a Fuel from Tank b Fuel Boost Pump c Water Separating Fuel Filter d Fuel Cooler e Install Fuel Fitting Connector 91 18078 at Either Location Fuel Fitting Connector 91 18078 Description Connects fuel pressure gauge to fuel system installed between fuel supply pump and VST unit MerCruiser EFI 1 1003 DIAGNOSTICS 3 15 Testing Mechanical or Electric Fuel Supply Pump used VST models Precautions Always disconnect battery cables from battery BEFORE working on fuel system to prevent fire or explosion Be careful when changing fuel system components gasoline is extremely mable and highly explosive under certain conditions Be sure that ignition key is OFF DO NOT smoke or allow sources of spark or flame in the area while changing fuel fil ters Wipe up any spilled fuel immediately Make sure that no fuel leaks exist before closing engine hatch DO NOT operate engine without cooling water being supplied to seawater pickup pump or pump impeller will be damaged and subsequent overheating damage may result NOTICE BEFORE proceeding refer to Precautions 1 Disconnect battery cables from battery 2 Remove fuel line from outlet side of
113. engines The adaptor set is actually Snap On MT337 300 e Remember that over 90 of all ECM s returned to warranty have tested ok they are not defective Stress to students that the ECM s seldom fail and to try to use the mindset of It s not the 2001 Model Year Model Line Summary from product line brochure VVVVVVVVY New Models 4 3 L EFI Alpha Bravo 2 or 3 210 pshp 4400 4800 rpm 5 0 L EFI Alpha Bravo 1 2 or 3 240 pshp 4400 4800 rpm 5 7 L EFI Alpha Bravo 1 2 or 3 260 pshp 4400 4800 rpm 350 Magnum MPI Alpha Bravo 1 2 or 3 300 pshp 4600 5000 rpm 350 Magnum MPI Horizon Alpha Bravo 1 2 or 3 300 pshp 4600 5000 rpm 350 Magnum standard Inboard 300 pshp 4400 4800 rpm 350 Magnum Ski Inboard 315 pshp 4600 5000 rpm 350 Magnum Horizon Inboard 300 pshp 4400 4800 rpm Black Scorpion MPI Ski Inboard 330 pshp 4800 5200 rpm p MX 6 2 MPI Bravo 1 2 or 3 320 pshp 4800 5200 rpm 1 12 EFI PRODUCT HISTORY Direct replacement for 7 4L MPI L29 Lighter and smaller better torque curve and fuel economy than the big block 350 base engine is disassembled and a new stroked forged crankshaft special ma chined rods cast hypereutectic alloy pistons and special camshaft are installed Externally identical to current 350 MPI Magnum New calibration MerCruiser EFI 1003 13 gt 6 2 MPI standard Inboard 320 pshp 4600 5000 r
114. es require a high volume low pressure floppy vane pump If an EFI engine is running cold below 160 F check to see if latest style thermostat hous ing with the plastic spacer sleeve is being used If not upgrade the components SB 94 8 Required fuel injector pod and ECM replacement This affects the 350 Magnum Tournament Ski TBI 1994 models only 0F215555 through 40F225894 Changes sys tem from a 12 psi to a 30 psi system to eliminate a flat spot or stumble on acceleration SB 94 9 Battery requirements for a MerCruiser product SB 94 12 EFI gasoline recommendations changes false 43 Read this bulletin carefully If the original ECM is used then the only recommended fuel is 87AKI fuel If the new ECM has been installed then higher octane fuel may be used Check sum numbers are listed in the bulletin SB 95 12 Engine compartment temperature specifications Vapor locking 1996 Model Year Model Line Summary from product line brochure MerCruiser EFI 1003 gt 5 7LX EFI Alpha Bravo 1 2 or 3 250 pshp 4400 4800 rpm p 350 Magnum EFI Tournament Ski Inboard 265 pshp 4400 4800 rpm EFI PRODUCT HISTORY 1 3 350 Magnum Tournament Ski Inboard 280 pshp 4600 5000 rpm 350 Magnum MPI Gen Bravo 1 2 or BlackHawk 300 pshp 4600 5000 rpm 7 4LX MPI Bravo 1 2 or 3 330 pshp 4200 4600 rpm 7 4L MPI Bluewater Inboard 340 pshp 4000 4400 rpm 454 Magnum MPI Bravo 1 2
115. eters as shown Figure A the ECM does not detect a problem If the sensor should happen to fall out of this window a code will be stored A known default value will replace the sensed value to restore engine performance If the sensor is out of range but still within the operating window of the ECM the problem will go undetected by the ECM and may result in a poor driveability condition A good example of this would be if the coolant ECT sensor was reading incorrectly and indi cating to the ECM that coolant temperature was at 20 F but actual coolant temperature was 175 F Figure B This would cause the to believe that the engine was running cold The ECM would then control the fuel injectors to deliver more fuel than was actually needed and result in an overly rich rough running condition This condition would not have caused a code to set as the ECM interprets this as within its range LOW Temperature 5 Volts Default Range Default Range lt 20 deg F Incorrect reading sent by an Out Of Range Acceptable sensor Sensor Operating Range lt 175 deg F This is the actual coolant reading that should have been sent the sensor Default Range Default Range HIGH Temperature 0 Volts Figure Figure B To identify a sensor which is out of range unplug it while running the engine After approxi mately two minutes the diagnostic code for that sensor will set a code and replace the sensed value with
116. fuel filter c Supply pump mechanical or electric d Vapor separator tank e Throttle body with 2 fuel injectors f Fuel pressure regulator g Return line to vapor separator tank EFI SYSTEM COMPONENTS OPERATION 2 69 Typical EFI MPI System with Cool Fuel Fuel Delivery Components see diagram on next page FUEL PUMP ELECTRICAL CIRCUIT When the ignition switch is turned to the RUN position the ECM will turn ON the fuel pump relay for two 2 seconds When the ignition switch is turned to the crank position the ECM turns the fuel pump relay ON causing the fuel pump to start If the ECM does not receive ignition reference pulses engine cranking or running it shuts OFF the fuel pump relay causing the fuel pump to stop When the pump operates fuel is drawn from the boat s fuel tank a and through the water separating fuel filter b WATER SEPARATING FUEL FILTER B This is a spin on cartridge similar to an oil filter that traps most fuel contaminants It is easily serviced by replacing the spin on cartridge The fuel then passes to the electric fuel pump c through a fuel line from the filter ELECTRIC FUEL PUMP C The electric fuel pump is mounted parallel to and beneath the fuel cooler d This is the only fuel pump used in the Cool Fuel fuel delivery system It is used to draw fuel out of the fuel tank and also to pressurize the fuel delivered to the engine Fuel is then sent to the fuel cooler d
117. g temperature 2 Ignition on or engine running 3 Scan tool not connected J 1 Circuits Circuit Normal Voltage Diag CKT Wire Possible bor Color EZE Codes Symptoms ED DTC s Injector DK Rough Idle Lack Of Power Ignition Control RED 0 0 Ref 453 BLK NOTE 5 NOTE 5 None Poor Performance Low ECM 0 0 TM Conta Stal Wil Restart In Bypass Mode ignal poe P i ie t Dee ror NOTE 1 Battery voltage for first two seconds then 0 volts NOTE 2 Varies with temperature NOTE 3 Varies with manifold vacuum NOTE 4 Varies with throttle movement NOTE 5 Less than 5 volt 500 mV MerCruiser EFI 1 1003 DIAGNOSTICS 3 65 ECM Connector and Symptom Chart Big Block V8 J 1 Circuits cont Circuit CKT Num ber Normal Voltage Engine Running Wire Color Knock Sensor Signal Only used on 7 4L MPI Diag nostic Trouble Codes DTC s Possible Symptoms Poor Fuel Economy Poor Performance Detonation Injector DK ECM 0 0 Fuel Pump Relay Driver LK DK GRN WHT 465 Ignition 24 Control Bypass Audio Warning Horn IAC B Low IAC A High TAN 0 NOTE B 1 amp 5 0 BLK NOTE 5 us DK GRN GRN Not Not BLK Usable Usable BLU Not Not WHT Usable Usable ONE U J1 J1 27 J1 28 Serial Data Rough Running Poor Idle Lack Of Performance No Start Lack Of Power Fixed T
118. gnum Bravo 1 2 or BlackHawk 415 pshp 4600 5000 rpm VY Model Line Changes from ReCertification book All models use the Cool Fuel System and serpentine belts All small block V6 and V8 models are Gen models The 262 Magnum EFI is now called the 4 3 L EFI It has been re rated at 210 pshp All previous versions of 5 7 liter 350 cubic inch EFI models are replaced with either the 5 7 L EFI Alpha Bravo 1 2 or 3 260 pshp 4400 4800 rpm or the new 350 Magnum listed below The Black Scorpion now features a 90mm throttle body a recalibrated ECM with a higher rpm range 4800 5200 rpm and a new lower fuel specification 87AKI minimum The fuel pressure regulator is still 30 psi Three new small block models 5 0 L EFI Alpha Bravo 1 2 or 3 models 240 pshp 4400 4800 rpm p Base engine is 305 GM roller cam Same 2 intake manifold as carbureted model p Same throttle body injection system as 5 7 350 models p MEFI 1 software in a MEFI 2 case EFI PRODUCT HISTORY 1 7 350 Magnum MPI Alpha Bravo 1 2 3 and BlackHawk stern drive models and Ski Inboard models 300 pshp 4600 5000 rpm and standard Inboard model 300 pshp 4400 4800 rpm p New MerCruiser MPI system New 4bbl intake manifold designed by MerCruiser and cast by Edelbrock Uses bronze cross over 75mm throttle body centrally located on intake manifold like a carburetor Magneti fuel injectors
119. h Intermittents 3 26 Quicksilver Digital Diagnostic Terminal Data Screen Information 3 27 3 i DIAGNOSTICS Page MEFI 1 Data Log Sheet 3 28 2 Data Log Sheet 3 29 3 Data Log Sheet 3 30 PCM 555 03 and ECM 555 Data Log Sheet DDT 3 32 DDT MerCruiser Ver 2 0 MEFI 3 502 Mag 3 33 DDT Functions 555 350 MAG MerCruiser Typical Bravo Model Shown Software Version 1 2 3 38 DDT Functions PCM 555 8 1 496 MerCruiser Typical Base Model Shown Software Version 1 2 3 40 MerCruiser Rinda Scan Tool 3 42 Models 3 42 2001 Scan Tool Version 4 0 3 42 Windows PC Software Available 3 43 Ordering New or Updating Older Scan Tools 3 43 MerCruiser Rinda Function Flowchart 3 44 MC Rinda I Data Sheet 3 46 MC Rinda II Data Sheet 3 47 MC Rinda Data Sheet 3 48 555 Data Log Sheet Rinda Scan Tool 3 49 General Service Precautions When Working On EFI Systems 3 50 Intermittent Faults 3 52 EFI Troubleshooting Guide MEFI Systems 3 53 On Board Diagnostic OBD System Check Typical Systems 3 57 Diagnostic Trouble Codes 3 59 1 Codes
120. has actually failed or the connections at the ECM have failed In one fashion or another the troubleshooting chart will have you check each wire for continuity and shorts and test the sensor for correct operation 2 When troubleshooting logged codes the circuit in question is not experiencing a failure at this time You are looking for an intermittent connection or an intermittent short circuit that is not present right now You must still check circuits for opens and shorts but you must wiggle wires and connectors during all tests in attempt to locate the poor connection Carefully look for subtle problems such as corroded connections and internal wiring harness splices and for connectors with a loose fit between the male and female pins 3 Codes rarely indicate a fault with the ECM Assume that the ECM is working correctly until complete and thorough troubleshooting procedures prove otherwise If no codes are present but you still have an observable symptom go to the diagnosis by symptom section usually called fuel injection system troubleshooting Match the observed symptom with the closest chart in the table of contents Carefully follow the troubleshooting chart to test each sus pect system or circuit The problem may be that a sensor is out of calibration or it may be that the problem has nothing to do with the EFI system If there are no codes and no observable symptoms then troubleshooting is finished MerCruiser EFI 10
121. he minimum cca mca and Ah Amp hour ratings required for use on MerCruiser products The Amp hour rating is used outside the USA and Canada GASOLINE ENGINES Minimum Required Engine CID L Cranking Battery Size 375 cca or 475 mca or 90 Ah 450 cca 575 mca or V8 Carb 90 Ah V8 550 cca or V8 Carb 700 V8 120 Ah 600 cca or 750 mca V8 Carb i or 150 Ah All EFI and MPI 750 cca or 950 mca Models or 180 Ah DIESEL ENGINES 750 cca or 950 mca or 180 Ah 6 6 GENERAL INFORMATION MerCruiser EFI 1003 Battery Cables Length and Size NOTE Battery should be located as close to engine as possible 1 Select proper size positive and negative battery cables using the chart 1 Add the positive and negative cable lengths together 2 Divide by 2 to obtain the average cable length IMPORTANT Terminals must be soldered to cable ends to ensure good electrical con tact Use electrical grade resin flux solder only Do NOT use acid flux solder as it may cause corrosion and a subsequent failure IMPORTANT Tapered post connectors with wing nut connections can be used The tapered posts must be used for the engine battery cables The wing nut connections should be used only for the power trim pump and accessories It is recommended that the wing nuts be replaced with regular nuts to ensure that the connections are tightened securely GASOLINE ENGINES Cable us Cable LT 7 1 2 9
122. he sensor Full voltage will be present when there is no vane on the sensor The crankshaft sensor is placed near a machined wheel on the crankshaft As the crank ro tates the camshaft sprocket also rotates at engine speed The camshaft signal is synchro nized with one of the crankshaft signal pull downs The PCM processes the voltage signal from the sensor to determine engine position and engine speed After 1 1 2 to 2 revolutions the PCM will sync the camshaft and crankshaft sensors and charge the secondary circuit of the coil It may be noted that PCM555 controllers do not have cooling fins as found on the con trollers previously used on Mercruiser EFI MPI engines These fins are not necessary on PCM555 s as they utilize low amperage coil driver circuits that do not generate as much heat as the controller s high amperage coil driver circuit The PCM555 uses its eight low cur rent coil driver circuits to control a high current driver circuit in a coil located on each cylinder 1003 EFI SYSTEM COMPONENTS OPERATION 2 39 PCM 555 IGNITION CIRCUIT UJ 0 II e M e x 1 m ss STARBOARD COILS E tc m WHT LT BLU zm PPL WHT BLK BRN W GRY w gt SPLICE 101 SPLICE 100 SPLICE 106 C 40 4 d amp d ds s II D e 17 48 49 20 2122 2 io 20 e 22 9 62 SPLICE 106
123. hift interrupt switch with the Bravo jumper lead P N 80559241 If the engine now runs better replace the shift interrupt switch If erratic spark is still present troubleshoot the secondary system with a Kv meter No Spark Troubleshooting 3 22 DIAGNOSTICS 1 Visually check the ignition coil for melted plastic on its outer case If the case is melted the tachometer lead gray or white is shorted to ground somewhere Isolate and repair before replacing the ignition coil Make sure that battery voltage is present at the purple power lead carbureted or red power lead EFI at the ignition coil If not isolate and repair the problem in the engine or boat harness Isolate the gray carbureted or white EFI tach lead at the negative side of the ignition coil as described in the previous section step 4 If spark is now present the tach lead is shorted to ground in the engine harness boat harness or in the tach itself Disconnect the 4 pin connector from the ignition module Carbureted models if spark is now present the shift cut out switch is stuck on or shorted closed Replace the switch and retest EFI models if spark is now present the ECM is sending bypass voltage to pin B of the ignition module and it is not supposed to The EFI system will have to be diagnosed at this time as there is not a problem with the EST system MerCruiser EFI 1003 MerCruiser EFI I 1003 Disconnect the 2 pin connector fro
124. il Bottle j Knock 1 k Knock 2 Fuel Level m Paddle Wheel Sea Temp n Transom Harness o Pitot p Steering Angle q DLC CAN Line S Fuel Injectors 1 8 t Ignition Coils 1 8 u Tach Signal W Fuel Pump Relay X Boost Fuel Pump y Cool Fuel Pump z Main Power Relay MPR aa Trim UP Relay bb Warning Horn cc Tabs dd Key ee Crank Position Sensor CPS ff Cam Position Sensor CMP gg Inputs hh PCM 555 Controller il Outputs jj Input Output EFI SYSTEM COMPONENTS OPERATION 2 5 NOILVH3dO SLN3NOdMWOO WALSAS 1 9 9 143 SMN 001 G M E C M Identification MEFI 1 93 Controller MEFI 1 or 2 96 Controller MEFI 3 98 Controller J2 Center of Hole Center af Hole 4 6 Center of Hala Center of Hole k 13 16 AIL E C M s MEFI 3 New Small GM Marine All current EFI engines use this ECM Original GM Marine E CM Housing ECM Housing Delphi ECM number 16236999 To Identify between have Hoatin nd i g desired idle speed the numbers 729 at the end Small block and V 6 not including ECM s have power reduction ofthe Model number shown below Black Scorpion Delphi ECM number 16237009 16210729 don t have floating desired idle speed All current big block and Black Scorpion 60729KA000351588 Note Long term every engine will get the floating desired idle ECM All other ECM s are
125. iming None 43 44 Rough Unstable or Incorrect Idle Rough Unstable or Incorrect Idle Poor Fuel Economy Poor Performance Detonation No Serial Data NOTE 6 NOTE 1 Battery voltage for first two seconds then 0 volts NOTE 2 Varies with temperature NOTE 3 Varies with manifold vacuum NOTE 4 Varies with throttle movement NOTE 5 Less than 5 volt 500 mV 3 66 DIAGNOSTICS MerCruiser EFI 1003 ECM Connector and Symptom Chart Big Block V8 J 2 Circuits Circuit Normal Normal Voltage Diag Wire Eua i r Possible bee Color Codes Symptoms a Done E Tea 21 23 Idle Rough Idle Poor Per m 5 d 5 formance Exhaust Odor Ground 2 7 Discrete 114 BLU None Switch Discrete TAN CEN mp Ignition Control PUR Ref WHT None No Restart High Poor Performance J2 11 E 9v REV 14 Exhaust Odor Rough Idle ignal NOTE 2 NOTE 2 RPM Reduction J2 18 MAP Lack Of Performance Exhaust Ground me 5 mr 5 Odor Stall Lack Of Power Surge Rough Idle Exhaust Odor J2 19 Discrete 2 20 Switch 923 WHT Signal NOTE 1 Battery voltage for first two seconds then 0 volts NOTE 2 Varies with temperature NOTE 3 Varies with manifold vacuum NOTE 4 Varies with throttle movement NOTE 5 Less than 5 volt 500 mV MerCruiser EFI 1003 DIAGNOSTICS 3 67 ECM Connector and Symptom Chart Big Block V8 J 2 Circuits cont Circui
126. ine supply the PCM with timing and RPM information If a failure occurs in these sensor circuits the engine will run extremely rough or stop running Check for continuity between the PCM and the sensor The normal resistance values for these sensors at 70 F 21 C are e Camshaft Position Sensor A to B 24 04 mohms and to C 24 05 mohms e Crankshaft Position Sensor A to B 23 2 mohms and B to C 23 21 mohms A malfunction of the crankshaft position sensor circuit will not set a fault A malfunction of the camshaft position sensor circuit will set a fault Splice 100 is Sensor Ground Splice 101 is Sensor Power 5V MerCruiser EFI I 1003 EFI SYSTEM COMPONENTS OPERATION 2 45 Engine Coolant Temperature ECT Sensor Circuit NOTE MEFI circuit shown ECM PCM 555 circuits are similar 72799 a Thermostat Housing b Engine Coolant Temperature ECT Sensor ECM wove n2 sax uras 4518 CIRCUIT DESCRIPTION The Engine Coolant Temperature ECT Sensor uses a thermistor to control the signal volt age to the ECM The ECM applies a voltage on CKT 410 to the sensor When the engine cool ant is cold the sensor thermistor resistance is high Therefore the ECM will see high signal voltage As the engine coolant warms the sensor resistance becomes less and the voltage drops ECT Sensor Temperature to Resistance Values Approximate pope mn 185 450 1 800 3 400 7 500 13 500 25 000 100 700 2 4
127. ines are connected with a data link harness the following features are enabled 1 One engine becomes the Master engine and the other becomes the Slave 2 If either engine enters power reduction mode the opposite engine will also enter power reduction 3 If the safety lanyard circuit is being used it only needs to be connected to the Master engine Both engines will stop if the lanyard is pulled on the Master engine 4 Both engines can be scanned from either engine s DLC Lanyard Stop Switch Harness P N 84 805745A2 can be used to connect a lanyard stop switch to early MEFI 1 models equipped with a 2 pin lanyard stop circuit connector at the rear of the engine near the flywheel housing When the Pink lead is connected to the black lead the will not fire the fuel injectors and the engine will stop Two harness kits can be used to connect 2 engines to the Dual Engine Lanyard Stop Switch P N 87 814324 2 If the 2 engines are connected with a Data Link Harness master slave then it is only neces sary to connect one lanyard stop switch harness to the Master Engine and to the Single En gine Lanyard Stop Switch P N 87 19674A2 When the lanyard is pulled on the single en gine stop switch the slave engine will also stop because of the Data Link Harness If you are going to use the Lanyard Stop Switch Circuits on a triple engine installation con nect the outer engines with a Data Link Harness master slave The
128. information is provided to ensure proper installation of brass fittings or plugs installed into fuel pump or fuel filter base e Use 592 Loctite Pipe Sealant with Teflon on threads of brass fittings or plugs DO NOT USE TEFLON TAPE e Brass fittings or plugs should first be threaded into fuel pump or fuel filter base until finger tight e Fittings or plugs should then be tighten an additional 1 3 4 to 2 1 4 turns using a wrench DO NOT OVERTIGHTEN To prevent over tightening when installing a fuel line the brass fittings should be held with a suitable wrench as fuel line connectors are tightened securely 6 4 GENERAL INFORMATION MerCruiser EFI 1003 Battery Requirements for MerCruiser Products Battery Ratings There are two major rating systems used in the USA for marine engine cranking batteries The most common is cca cold cranking amps which rates the cranking amps at 0 F The second system mca marine cranking amps rates the cranking amps at 32 The mca marine cranking amps rating of a given battery is always higher than the cca cold cranking amps rating There is a third rating system that some discount stores use which rates the cranking amps of a battery at 80 F The advertised cranking amps of these batteries is high while the actual cca of it is very low Cold Cranking Amps CCA This figure represents in amps the current flow the battery can deliver for 30 seconds at 0 Fahrenheit without dropping be
129. ing as the key is turned on make sure the ECM is powering up check the fuses and the system relay On TBI models the fuel pressure must be constant at all speeds and must be 30 psi 2psi On MPI models the fuel pressure varies with engine vacuum Fuel pressure will be high dur ing cranking low at idle and increase proportionally as the throttle is opened to the wide open position Disconnect the vacuum line to find the regulator s rated pressure then reconnect the vacuum line to make sure the pressure drops at idle Pressure specifications are 30 36 or 43 psi 2psi depending on model and year Pressure usually drops about 6 psi at idle from the regulator s rated specification Refer to the service manual for specifications If fuel pressure drops at higher speed and higher engine loads check the boat s fuel system the supply system for restrictions with an accurate vacuum gauge and clear hose at the water separating fuel filter s inlet As the engine is run from idle to wide open throttle and back to idle the clear hose must not show the presence of any air bubbles and the vacuum gauge must not read higher than 2 in hg Refer to Service Bulletin 99 7 for additional information If the supply system tests ok but the fuel pressure is low at high speeds and loads replace the water separating fuel filter and retest If pressure is still low most likely the fuel pump is defective XII Unplug and inspect the main harness 10 pin
130. injectors are eight electric solenoid operated devices that meter pressurized fuel to each engine cylinder The Fuel Injectors are controlled by the Electronic Control Module ECM which grounds the injector coil to open the injector nozzle and allow fuel to spray into the intake manifold next to the intake valve Fuel pressure to the injectors is controlled by the Fuel pressure Regulator FUEL PRESSURE REGULATOR K The Fuel Pressure Regulator is located at the forward end of the Fuel Rail It is a diaphragm operated relief valve that maintains constant pressure differential across the injectors at all times An intake manifold vacuum line is attached to the regulator housing and a spring is mounted inside the housing pushing on the diaphragm Engine manifold vacuum and the spring counteract each other to apply the correct pressure in the regulator diaphragm under all engine operating conditions Fuel pressure is 34 38 PSI FUEL RAIL RETURN PASSAGE L Fuel that is not used by the injectors is bled off and sent back to the Vapor Separator Tank VST through the Fuel Rail Return Passage VAPOR REGULATOR ASSEMBLY M The return fuel from the fuel rail enters the Vapor Separator Tank VST Fuel vapors are bled off by the Vapor Regulator Assembly and are sent to the intake manifold This system avoids vapor locking and does not require a return fuel line to the boat s fuel tank 2 62 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003
131. input impedance digital meter for accurate readings The ECM can also perform a diagnostic function check of the system It can recognize operational problems and store a code or codes which identify the problem areas to aid the technician in making repairs 1003 EFI SYSTEM COMPONENTS OPERATION 2 23 The following sensors interact with the MANIFOLD ABSOLUTE PRESSURE SENSOR MAP 6 The Manifold Absolute Pressure Sensor MAP is a three wire sensor and is mounted at the rear of the intake plenum It is a pressure transducer that measures the changes in intake manifold pressure caused by engine load and speed The MAP sensor also is used to measure barometric pressure under certain conditions which allows the ECM to automatically adjust for different altitudes Signal voltage will vary from 1 1 5 volts at idle to 4 4 8 volts at wide open throttle WOT A map sensor failure will log in a 33 or 34 failure code DISTRIBUTOR REFERENCE SIGNAL DIST REF 2 A Distributor Reference Signal Dist Ref is sent to the ECM from the Ignition Module in the distributor housing This reference signal is the timing signal for ignition timing and pulsing the fuel injectors as well as the RPM counter for the ECM Problems with this circuit could set a 41 or 42 failure code ENGINE COOLANT TEMPERATURE SENSOR ECT 10 The Engine Coolant Temperature Sensor ECT is located on the port side of the thermostat housing It sends a signal to the
132. ion e SB 2000 14 Black Sensor Failures on MEFI 3 with ThunderBolt distributors 2002 Model Year Model Line Summary from product line brochure 4 3 L EFI Alpha Bravo 2 or 3 210 pshp 4400 4800 rpm 5 0 L EFI Alpha Bravo 1 2 or 3 240 pshp 4400 4800 rpm 5 7 L EFI Alpha Bravo 1 2 or 3 260 pshp 4400 4800 rpm 350 Magnum Alpha Bravo 1 2 or 3 300 pshp 4600 5000 rpm 350 Magnum MPI Horizon Alpha Bravo 1 2 or 3 300 pshp 4600 5000 rpm MX 6 2 MPI Bravo 1 2 or 3 320 pshp 4800 5200 rpm 496 Mag Bravo 1 2 or 3 375 pshp 4400 4800 rpm 496 Mag HO Bravo 1X 2X or 3X 425 pshp 4600 5000 rpm 350 Magnum MPI Inboard 300 pshp 4400 4800 rpm 350 Magnum Horizon Inboard 300 pshp 4400 4800 rpm 6 2 MPI Inboard 320 pshp 4600 5000 rpm 8 1S Horizon Inboard 370 pshp 4200 4600 rpm 8 1S HO Inboard 420 pshp 4400 4800 rpm 350 Magnum MPI Tow Sports 315 pshp 4600 5000 rpm Black Scorpion Tow Sports 330 pshp 4800 5200 rpm MX 6 2 Black Scorpion Tow Sports 340 pshp 4800 5200 rpm VVVVVVVVVVVVVVVY New Models 4 3 MPI Alpha Bravo 2 or 3 220 pshp 4400 4800 rpm 5 0 L MPI Alpha Bravo 1 2 or 3 260 pshp 4600 5000 rpm vv 1 14 EFI PRODUCT HISTORY MerCruiser EFI 1003 15 350 Magnum Alpha Bravo 1 2 or 3 300 pshp 4600 5000 rpm 350 Magnum MPI Horizon Alpha Bravo 1 2 or 3 300 pshp 4600 5000 rpm MX 6 2
133. ion can then be reviewed by the service technician to see what caused the malfunction To check loss of DTC memory disconnect TP sensor and idle engine until the MIL comes ON A trouble code should be stored and kept in memory when ignition is turned OFF If not the ECM is faulty When this test is completed make sure that you clear the DTC 22 from memory An intermittent MIL with no stored DTC may be caused by the following e Ignition coil shorted to ground and arcing at ignition wires or plugs e MIL wire to ECM shorted to ground e Poor ECM grounds Go to ECM wiring diagrams e Check for an electrical system interference caused by a sharp electrical surge Normally the problem will occur when the faulty component is operated e Check for improper installation of electrical options such as lights ship to shore radios sonar etc e Check that knock sensor wires are routed away from spark plug wires ignition system components and charging system components e Check for secondary ignition components shorted to ground or an open ignition coil ground coil mounting brackets e Check for components internally shorted to ground such as starters alternators or relays All Ignition Control IC module wiring should kept away from the alternator Check all wires from the ECM to the ignition control module for poor connections 3 52 DIAGNOSTICS MerCruiser EFI 1003 EFI Troubleshooting Guide Systems Trouble
134. ions Black Scorpions with serial number 0L0058999 and below must use fuel with a 98 RON minimum Black Scorpions with serial number 0L0059000 and above can use fuel with a 90 RON minimum USING REFORMULATED OXYGENATED GASOLINES USA ONLY This type of gasoline is required in certain areas of the USA The two types of oxygenates used in these fuels is Alcohol Ethanol or Ether MTBE or ETBE If Ethanol is the oxygenate that is used in the gasoline in your area refer to Gasolines Containing Alcohol These Reformulated Gasolines are acceptable for use in your MerCruiser engine MerCruiser EFI 1003 GENERAL INFORMATION 6 1 GASOLINES CONTAINING ALCOHOL If the gasoline in your area contains either methanol methyl alcohol or ethanol ethyl alcohol you should be aware of certain adverse effects that can occur These adverse effects are more severe with methanol In creasing the percentage of alcohol in the fuel can also worsen these adverse effects Some of these adverse effects are caused because the alcohol in the gasoline can absorb moisture from the air resulting in a separation of the water alcohol from the gasoline in the fuel tank The fuel system components on your MerCruiser engine will withstand up to 1096 alcohol content in the gasoline We do not know what percentage your boat s fuel system will withstand Contact your boat manufacturer for spe cific recommendations on the boats fuel system compo
135. ir Control IAC 8 Throttle Position TP Sensor 9 Engine Coolant Temperature ECT Sensor 10 Electronic Control Module ECM 11 Fuel Pump Relay 12 Ignition System Relay 13 Fuses 15 Amp Fuel Pump 15 Amp ECM DLC Battery 10 Amp Injector Ignition Knock Module 14 Harness Connector To Starting Charging Harness 15 Positive Power Wire To Engine Circuit Breaker 16 Oil Pressure Audio Warning System 17 Load Anticipation Circuit 18 Water Temperature Sender 19 Gear Lube Bottle Not used on Inboard models 20 Intake Air Temperature IAT Sensor lt 4 8 WIRING DIAGRAMS MerCruiser EFI 1003 Fuel Pump and Fuel Injector Wiring Operation MEFI 1 and MEFI 2 467 DK BLU INJECTOR DRIVER INJECTORS ONE IF EFI FOUR IF MPI INJECTORS 2 3 5 8 IF FOUR 450 BLK WHT INJECTOR GROUND TO INJECTOR FUSE lt 439 PNK BLK 450 BLK WHT INJECTOR GROUND 468 DK GRN INJECTOR DRIVER TO IGNITION RELAY INJECTORS ONE IF EFI FOUR IF MPI INJECTORS 1 4 6 7 IF FOUR PORT FUEL JUMPER 901 WHT MPI ONLY PORT FUEL JUMPER 901 WHT MPI ONLY FUEL PUMP 465 GRN WHT RELAY DRIVER 450 Ta 7 FUEL PUMP FUSE 120 GRY 150 EUN FUEL PUMP pem FUELPUNP BEEAY 441 BRN or BLU WHT IAC COIL A HIGH 442 RED or BLU BLK IAC COIL A LOW TO ECM BAT FUSE 443 YEL or GRN WHT IAC COIL B HIGH 444 GRN BLK p IDLE AIR CONTROL MOTOR EE L
136. ky blinky A Clearing codes with the winky blinky requires 2 separate procedures depending on whether you are working on a MEFI 1 system or a MEFI 2 or 3 system 1 MEFI 1 It is very difficult to clear codes on a MEFI 1 system because the engine must be cranked and started during the code clearing process If the voltage at the ECM drops below 6 9 volts for even the briefest period of time the will reset and forget to clear the codes a Install winky blinky to the DLC Key On Engine Off KOEO Turn the winky blinky to ON d While in Neutral cycle the throttle from 0 to 10096 and back to 0 e Turn the winky blinky to OFF for at least 5 seconds f Turn the ignition key to OFF for at least 20 seconds 9 Start and run the engine for at least 20 seconds h Turn the ignition key to OFF for at least 20 seconds i Verify that the codes were erased 2 MEFI 2 and 3 Codes can be easily cleared on these models because the engine does not have to be started a Install winky blinky to the DLC Key On Engine Off KOEO Turn the winky blinky to ON d While in Neutral cycle the throttle form 096 to 10096 and back to 0 e Turn the ignition key to OFF for at least 5 seconds f Verify that the codes were erased 3 56 DIAGNOSTICS MerCruiser EFI 1003 On Board Diagnostic System Check Typical Systems ECM 461 ORN BLK or ORN J1 18 J1 32 450 BLK WHT or BLK J1 14 DLC iI
137. l rail Ski 5 7L 2 66 EFl SYSTEM COMPONENTS OPERATION MerCruiser EFI 0804 e MEFI 1 22 3 ECM Fuel Regulator Identification Contd Engine Color System Regulator Model Code psi kPa P N Comments V8 5 7L MEFI 1 MPI Cool Fuel on Port side Gen engines Keihin injectors 350 Mag MPI Pink 30 207 807952 1 Regulator on fuel cooler No ring on hose Bravo Inbrd Ski fitting Black Scorpion Ski V8 5 7L 6 2L MEFI 2 3 MPI Cool Fuel on Port side Gent engines Magneti Marelli injectors 350 Mag MPI Pink 30 207 807952 1 Regulator on fuel cooler No ring on hose Alpha Bravo fitting Inbrd Ski and MX 6 2 MPI Bravo Inbrd V8 5 7L 6 2L MEFI 3 MPI Cool Fuel on Port side Gent engines injectors Black Scorpion Pink 30 207 807952 1 Regulator on fuel cooler No ring on hose 5 7L amp 6 2L fitting V8 7 4L L29 MEFI 2 3 MPI Cool Fuel GM MPI intake plenum injectors 7 4L MPI Blue Brown 43 296 861126 1 Regulator on fuel cooler Green ring on hose Bravo amp Inbrd fitting GM regulator on the fuel rail does not operate or control fuel psi V8 7 4L MEFI 1 GM TBI Cool Fuel GM TBI intake GM TBU 7 4LX EFI Bravo Pink 30 207 807952 1 Regulator on fuel cooler No ring on hose 7 4L EFI Inbrd fitting V8 7 4L 8 2L MEFI 1 MPI VST MerCruiser MPI intake injectors All 7 4L amp 8 2L Unknown 36 248 805227 1 Regulator on fuel rail Hose fitting p
138. ld vacuum while the fuel regulator on TBI models cool fuel models must be vented to atmospheric pressure usually at the flame arrestor The PCV valve used on newer models is a calibrated air leak if it is missing or the incorrect valve is installed engine opera tion will be effected Check for any other additional air leaks in the induction system such as throttle body and intake manifold gaskets If the normal IAC counts for the engine are known then any air leak will result in a lower IAC count than normal Unplug and inspect the ECM J 1 and J 2 connectors Make sure there are no ECM pins bent over and that all of the correct pins are present Refer to the service manual charts for the pins used and not used Look for signs of tampering corrosion damage to the pin locking mechanisms melted insulation and any other evidence of shorts or other damage Unplug and inspect as many of the sensors and actuators as you can reasonably access Look for signs of tampering corrosion damage to the pin locking mechanisms melted insulation and any other evidence of shorts or other damage Based on the results of this inspection further inspec tion of the harness may be necessary Remember that there are many internal splices in the har ness that may be damaged or defective If there is damage on the external connections you will have to inspect several of the internal splices to verify that the damage is not also present at these locations Check for
139. low 1 2 volts per cell 7 2 volts on a standard 12 volt battery The higher the number the more amps it can deliver to crank the engine CCA x 1 3 2 MCA Marine Cranking Amps MCA This figure is similar to the CCA test figure except that the test is run at 32 Fahrenheit instead of 0 MCA x 77 CCA This is more in line with actual boat operating conditions Reserve Capacity This figure represents the time in minutes that a fully charged battery at 80 Fahrenheit can deliver 25 amps without dropping below 1 75 volts per cell 10 5 volts on a standard 12 volt battery The reserve capacity rating defines the length of time that a typical vehicle can be driven after the charging system fails The 25 amp figure takes into account the power required by the ignition lighting and other accessories The higher the reserve capacity rating the longer the vehicle could be driven after a charging system failure Amp Hour Rating MerCruiser EFI I 1003 The ampere hour rating method is also called the 20 hour rating method This rating repre sents the steady current flow that the battery will deliver for 20 hours while at 80 Fahrenheit without dropping below 1 75 volts per cell 10 5 volts on a standard 12 volt battery The rating is actually the steady current flow times the 20 hours Example A 60 amp hour battery will deliver 3 amps continuously for 20 hours GENERAL INFORMATION 6 5 The following battery charts list t
140. lower intake as previous 350 Magnum MPI models 43 psi fuel regulator Service Notes Refer back to all previous service notes 1996 1 2 models have the lanyard stop emergency stop switch lead removed from the wiring harness This was a pink lead connected to J1 21 When grounded the ECM would not fire the fuel injectors 1996 1 2 models have the dedicated master slave connector removed from the wiring harness The master slave function is now part of the DLC connector All 1996 models use the MEFI 2 ECM case but are loaded with MEFI 1 GM 93 software MEFI 2 cases can be identified as having long mounting bolts instead of the short bolts used on MEFI 1 cases Power reduction mode has been disabled on all 1996 models If it is a MEFI 2 case it does not have power reduction regardless of the software loaded in side A factory installed fuel cooling kit was available for 7 4 L 454 Magnum and 8 2 L Inboard models This kit is also available for field installation to help solve vapor locking problems in boats with higher than normal bilge temperatures Call technical service if a kit is need ed If a new style VST system is flooding the engine through the black A1 vent line check for a plugged fitting for the yellow Tygon vent line at the throttle body It may be neces sary to drill out hardened Loctite to allow air to flow through the fitting SB 96 4 Introduction of the Quicksilver DDT scan tool SB 96 9 Updates to th
141. ls To determine the density of the air in the intake manifold we need to know the intake manifold vacuum which we measure with the MAP Manifold Absolute Pressure sensor It is important to remember that a MAP sensor measures the manifold pressure above absolute zero like a barometer while a conventional vacuum gauge measures the manifold pressure below the current atmospheric pressure The use of the Manifold Absolute Pressure Sensor allows us to compensate for variations in atmospheric pressure due to weather and altitude chan ges A conventional vacuum gauge would not provide us with this needed information NOTE While the temperature of the air does affect its density not all engines use an IAT in take air temperature sensor If no IAT is present then the assumes 75 degree Fahren heit for all density calculations If an IAT is present then the ECM can more accurately deter mine the air s density However the amount of correction the IAT adds is a relatively small amount approximately 10 maximum change in fuel flow In review our standard unmodified production engines flow a repeatable and therefore known amount of air at any specific engine rpm and manifold pressure With this knowl edge the ECM can be programmed to deliver the correct amount of fuel from the combination of the speed sensor distributor signal and density information from the MAP sensor It is often said that the speed density system runs in
142. m 4 3 Typical Starting and Charging System Harness Small Block MEFI 3 4 4 EFI System Harness Typical MEFI 3 4 5 Throttle Body Injection 4 5 EFI System Harness Typical MEFI 3 Small Block Multi Port Injection 4 6 EFI System Harness 7 4L Multi Port Injection L29 MEFI 2 4 7 EFI System Harness 454 502 8 2L Models except L29 MEFI 3 4 8 Fuel Pump and Fuel Injector Wiring Operation 4 10 MEFI 1 and MEFIZ2 4 10 Wiring Diagram V6 and Small Block V8 1 of 4 4 11 44 WIRING DIAGRAMS ECM Wiring Diagram MEFI 3 V6 and Small Block V8 2 of 4 ECM Wiring Diagram MEFI 3 with Mercury Distributor V6 and Small Block V8 3 of 4 ECM Wiring Diagram MEFI 3 with GM EST Distributor V6 and Small Block V8 4 of 4 ECM Wiring Diagram MEFI 3 Big Block V8 1 of 4 ECM Wiring Diagram MEFI 3 Big Block V8 2 of 4 ECM Wiring Diagram MEFI 3 Big Block V8 3 of 4 ECM Wiring Diagram MEFI 3 Big Block V8 4 of 4 555 Charging Harness 555 Ignition 555 Coil Harness Circuit MerCruiser EFI I 1003 Starting and Charging System Harness V6 Throttle Body Injection MEFI 1 with VST Fuel System A Audio Warning System 1 Drive Unit Oil Level 2 Oil Pres
143. m the ignition module With the Key ON check for bat tery voltage at both the pink and brown terminals of the harness a Ifthere is not battery voltage at the pink terminal replace the 2 wire harness as the filter is most likely blown open b Ifthere is not battery voltage at the brown terminal replace the ignition coil as the pri mary windings have most likely melted open because of a shorted tach lead c Reconnect the 2 pin connector to the ignition module when finished If spark is still not present remove the distributor cap and check the pickup coil for resist ance and short to grounds Resistance across the green and white leads must be 500 1500 ohms 750 850 preferred and the reading must be steady Resistance be tween the green lead and the distributor frame must be infinity and resistance between the white lead and the distributor frame must be infinity If any of these readings differ from specifications replace the pickup coil Verify that the timer core is still magnetic This is the part that rotates above the pickup Coll If spark is still not present you will need to false trigger the module to determine if it is opening and closing the primary circuit Proceed as follows If still isolated reconnect the tach lead to the ignition coil Connect a voltmeter to the gray tachometer lead bullet connector near the ignition coil Set the meter to read DC volts Connect an air gap tester from the coil s se
144. mechanical or electric fuel supply pump or from inlet side of VST tank 3 Install Fuel Pressure Connector 91 18078 to fuel supply pump or VST tank and reinstall fuel line Tighten connector and fuel line securely 4 Connect fuel pressure test gauge 0 15 psi to connector 5 Reconnect battery cables start engine and run at 1800 RPM If engine will not start crank engine to obtain reading 6 Fuel pressure should be within specifications 7 9 psi If not replace fuel pump Fuel Fitting Connector 91 18078 Description Connects fuel pressure gauge to fuel system installed between fuel supply pump and VST unit 3 16 DIAGNOSTICS MerCruiser EFI 1003 Testing Mechanical or Electric Fuel Supply Pump used VST models cont Throttle Body Injection With Vapor Separator Tank VST Attach Fuel Fitting Connector at Either Location 73895R1 a Fuel line from boat s fuel tank b Water separating fuel filter c Supply pump mechanical or electric d Vapor separator tank e Throttle body with 2 fuel injectors f Fuel pressure regulator g Return line to vapor separator tank MerCruiser EFI I 1003 DIAGNOSTICS 3 17 Checking for Restrictions Vapor Lock Problems Fuel Delivery Systems If there are any restrictions in the fuel delivery system the engine may experience vapor lock and other driveability problems Fuel supply problems can be checked by using a vacuum gauge on a water separating
145. mperature EMCT sensors are located on the top of each exhaust manifold The EMCT sensors are thermistors immersed in the engine exhaust stream Low temperatures produce high resistance while high temperatures cause low re sistance The normal resistance values for the EMCT sensors at 70 F 21 C is 11 01 kohms A malfunction of the EMCT circuit s will set a fault of Port EMCT CKT Hi Port EMCT CKT Lo Port EMCT CKT Overheat STB EMCT CKT Lo STB EMCT CKT Hi or STB EMCT CKT Overheat Splice 100 is sensor ground 496 Exhaust Manifold w o Water Rail 2 52 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 0804 Sea Pump Pressure Sensor The sea pump sensor measures water inlet pressure or water block pressure It is located at the sea pump inlet hose Normal diagnostic tool ranges are 1 5 psi 7 34 kPa at idle and 7 17 PSI 48 117 kPa at WOT To check if sensor is within range the diagnostic tool reading with key ON should be approximately zero The normal resistance value for the oil pressure sensor at 70 F 21 C is A to B 31 5 kohms and A to C 42 9 kohms A malfunction of the sea pump sensor circuit will set the fault of Sea Pump CKT Hi Sea Pump CKT Lo or Sea Pump PSI Lo Splice 100 is sensor ground Splice 101 is sensor power 5V 77512 a Sea Pump Pressure Sensor ECM 555 engines have this sensor on the power steering fluid cooler or transmission fluid cooler MerCruiser EFI I 1003 EFI SYSTEM COMPONENTS OPERA
146. n connect a Lanyard Stop Switch Harness to the Master engine and another harness to the Center engine Finally connect these 2 stop circuit harnesses to a Dual Engine Lanyard Stop Switch If you are going to use the Lanyard Stop Switch Circuits on a four engine installation connect the outer engines with a Data Link Harness master slave then connect the inner engines with another Data Link Harness Connect a Lanyard Stop Switch Harness to the Master Inner engine and another harness to the Master Outer engine Connect both of these har nesses to a Dual Engine Lanyard Stop Switch 2 8 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 Early 1 Master Slave Data Link Connector DLC and Safety Lanyard Switch Circuits DUAL ENGINE DATA LINK MULTIPLE ENGINE 916 YEL MASTER SLAVE SOME MODELS WILL HAVE THE 461 ORN BLK 1 18 SERIAL DATA DUAL ENGINE DATA LINK MOVED TO THE 450 BLK WHT DLC TO ECM BAT 451 WHT BLK 31 7 DIAGNOSTIC TEST TERMINAL 419 BRN WHT 42 31 MALFUNCTION INDICATOR LAMP LANYARD STOP CONNECTOR NOT PRESENT 942 PNK 11 21 ON LATER MODELS IMPORTANT The data link harness P N 84 805696A2 has a jumper wire on one of the connectors This connector should be connected to the port engine The side that has the plug with the jumper wire will be considered the Slave Engine the other side be comes the Master Engine This is important to note for future service
147. n shown is arranged for visual clarity and ease of circuit identification 2 gt 3 76063 MerCruiser EFI 1003 WIRING DIAGRAMS 4 5 EFI System Harness Typical 3 Small Block Multi Port Injection NOTE All BLACK wires with a ground symbol are interconnected within the EFI system har ness NOTE Component position and orientation shown is arranged for visual clarity and ease of circuit identification 1 Fuel Pump 13 Fuse 15 Amp Fuel Pump 2 Distributor Fuse 15 Amp ECM DLC Battery Fuse 10 3 Coil Amp ECM Injector Ignition Knock Module 4 Knock Sensor KS Module 14 Harness Connector To Starting Charging 5 Data Link Connector DLC Harness 6 Manifold Absolute Pressure MAP Sensor 15 Positive Power Wire To Engine Circuit 7 Air Control IAC 8 Throttle Position TP Sensor 9 Engine Coolant Temperature ECT Sensor 10 Electronic Control Module ECM 11 Fuel Pump Relay 12 Ignition System Relay BLK BLU BRN GRY GRN ORN PNK PUR RED TAN WHT YEL LIT DRK Breaker 16 Shift Plate Not used on Ski models 17 Oil Pressure Audio Warning System 18 Gear Lube Bottle Not used on Ski models 19 Fuel Pressure Switch 20 Intake Air Temperature IAT Sensor BLACK BLUE BROWN GRAY GREEN ORANGE PINK PURPLE RED TAN WHITE YELLOW LIGHT DARK 1HWHfhd 76064 4 6 WIRING DIAGRAMS MerCruiser EFI 1003
148. nce and retard electronically by the ECM This electronic advance becomes much more exact and reliable just as EST is more exact and reliable when compared to the breaker point ignition system In order for the ECM to properly calculate spark advance it must always know at what speed the engine is running The engine speed signal is accomplished by a circuit within the EST module which converts the pickup coil voltage to a square wave digital reference signal that can be used by the ECM This square wave engine speed reference signal is known as REF HI The must also have something to compare the REF HI value against Therefore additional line is provided between the ECM and the EST module that is known as REF LO These two lines between the ECM and the distributor provide a precise indication of engine speed The two other lines between the ECM and distributor which control the Electronic Spark Timing EST operation are known as the bypass and IC Ignition Control circuits MODULE RELAY ADVANCE il Battery Ignition Coil Trigger Signal ignition Control mp Dist Reference HIGH mj 9 Not Activated Dist Reference LOW 2 32 EFl SYSTEM COMPONENTS OPERATION MerCruiser EFI 1003 EFI Engines with High Energy Ignition and Electronic Spark Timing EST MerCruiser EFI I The Electronic Fuel Injection EFI is controlled by an Electronic Control Module ECM This module is the ner
149. nce that outboard ignition systems are very noisy with lots of RFI interference Our new DMT 20004 Digital Tachometer Multi meter represents real breakthrough technology in the marine service industry It s the only meter on the marine market today designed to read accurately in high RFI environments The only meter that measures RPM on both 2 and 4 cycle marine engines while recording maximums and minimums simultaneously Give your service personnel the latest in innovative marine technology the DMT 2000A Digital Tachometer Mul ti meter from Mercury Marine Order today Complete the order form below and we guarantee that your marine service life will get just a little easier DMT 2004 similar to DMT 2000A It has a serial port for connecting Replacement ferrite core 91 854012 meter to a CDS unit Interface module 91 854013 1 Hard carrying case 91 854014 1 User s guide 91 854015 1 Test Leads 91 802651 Optional Accessories 8 ft 2 4m inductive pick up 84 854016 T extension Clamp on Current Probe 91 802650 1 Direct Voltage Adaptor 91 89045 1 Order on MIDAS or contact Quicksilver Sales at In USA Phone 920 929 5589 Fax 800 457 8736 Quicksilver Marine Parts and Accessories Products of Mercury Marine Fond du Lac WI 54936 1939 USA MerCruiser EFI 1 1003 DIAGNOSTICS 3 3 Mercury 2000 FAQ S e Q What battery does the DMT 2000A take and where is it located A The DMM requires a 9 volt alkaline batter
150. nds and then ON again several times to get fuel pressure to its maximum Record this initial pressure reading Energize tester one time and note pressure drop at its lowest point Disregard any slight pressure increase after drop hits low point By subtracting this second pressure reading from the initial pressure we have the actual amount of injector pressure drop Repeat Step 2 on each injector and compare the amount of drop Usually good injectors will have virtually the same drop Retest any injector that has a pressure difference of 1 5 psi 10 kPa more or less than the average of the other injectors on the engine Replace any injector that fails the retest If the pressure drop of all injectors is within 1 5 psi 10 kPa of this average the injectors appear to be flowing properly Reconnect them and review Troubleshooting NOTE The entire test should not be repeated more than once without running the engine to prevent flooding This includes any retest on faulty injectors MerCruiser EFI 1003 Test Example READING INITIAL PRESSURE FUEL PRESSURE GAGE INJECTOR CONNECTOR nd READING PRESSURE AFTER DROP 1st 38 psi 38 psi 38 psi 38 psi 38 psi 38 psi 38 psi 38 psi Reading 262 kPa 262 kPa 262 kPa 262 kPa 262 kPa 262 kPa 262 kPa 262 kPa 2nd 19 psi 17 psi 21 psi 19 psi 19 psi 19 psi 19 psi 19 psi Reading 181 kPa 117 kPa 145 kPa 131 kPa 131 kPa 131 kPa 131 k
151. ne 454 Magnum EFI Tournament Ski Inboard p Slight modification to the throttle body and new ECM program are only changes from original 502 p 0F130439 and above will use the new style VST MerCruiser EFI 1003 EFI PRODUCT HISTORY 1 1 3 new small block models 350 Magnum EFI Alpha One 250 pshp 4400 4800 rpm 350 Magnum EFI Tournament Ski Inboard 265 pshp 4400 4800 rpm 5 7 Liter EFI Bravo One Three 250 pshp 4400 4800 rpm p All use 350 magnum roller lifter base engine gt GM throttle body injection Two 51 mm bores with 2 fuel injectors Same intake man ifold as carbureted models gt VST fuel system However the hi pressure pump has different electrical connection male connector body female pins and vent fitting is angled towards the hi pressure pump Small block models use a lower output hi pressure electric pump All small block VST systems are the New style system All use a mechanical fuel supply pump that is similar to carbureted models Delco EST ignition However the shift cut out switch is in the Ignition Control IC line between the ECM and the ignition module The switch is unique to EFI engines and is normally CLOSED p 65 amp alternator gt MEFI 1 Service Notes All 1994 model year engines use MEFI 1 GM 93 software ECMs If an EFI engine is running cold below 160 F check to see if latest style thermostat housing with the plastic sp
152. nents fuel tanks fuel lines and fittings Be aware that gasolines containing alcohol may cause increased e Corrosion of metal parts e Deterioration of rubber or plastic parts e Fuel permeation through rubber fuel lines e Starting and operating difficulties FIRE AND EXPLOSION HAZARD Fuel leakage from any part of fuel system can be a fire and explosion hazard which can cause serious bodily injury or death Careful periodic inspection of entire fuel system is mandatory particularly after storage All fuel components including fuel tanks whether plastic metal or fiberglass fuel lines fittings fuel filters and carburetors fuel injection components should be in spected for leakage softening hardening swelling or corrosion Any sign of leakage or deterioration requires replacement before further engine operation Because of possible adverse effects of alcohol in gasoline it is recommended that only alcohol free gasoline be used where possible If only fuel containing alcohol is available or if the presence of alcohol is unknown in creased inspection frequency for leaks and abnormalities is required IMPORTANT When operating a MerCruiser engine on gasoline containing alcohol storage of gasoline in the fuel tank for long periods should be avoided Long periods of storage common to boats create unique problems In cars alcohol blend fuels normally are consumed before they can absorb enough moisture to cause trouble but boats often
153. ng Desired RPM mode and adjusts the Load Anticipation mode IAC count accordingly This allows the ECM to learn the best IAC bypass air position to use for shifting each particular boat NOTE The Load Anticipation mode is on MIE 454 502 cid inboard engines also Shift Switch Operation The Shift Switch is used on Alpha models only The switch is normally closed completing a circuit from the ECM s J2 9 terminal through the shift switch to ground When shifting the switch will open the J2 9 wire between the ECM and ground This will cause the to go and lower the IAC motor count and retard the ignition timing to help the shifting When the shift switch is back in the normal position ignition timing and IAC motor count are restored 2 14 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 ECM PCM 555 Identification Typical ECM Calibration Label An can be readily identified by the two wire harness connectors 3 4 3L ALPHA Typical ECM Calibration Label 864270 3 a Engine Model 884521 b Calibration Part Number MY2002p5AAAV 0038 4 3 ALPHA P AA12345678 c Model Year Typical PCM Calibration Label A PCM can be readily identified by the three wire harness nectors a Connector A b Connector B c Connector C d POM 555 a 77498 496 MAG HO Typical PCM Calibration Label 863619 6 a Engine Model 859610 b Calibration Part Number MY2002pOAACS 009
154. ng gasket was used in production on Bravo s 0L014226 and below and Inboards 0L002190 and below SB 97 14 Engine specifications for new 1998 models SB 97 21 Required ECM replacement This effects 1998 350 Magnum MPI and 7 4 L MPI stern drive and inboard models See bulletin for serial numbers Calibration problems with warning system oil pressure May also require moving the brown lead from J1 4 to J1 6 SB 97 24 Service tools Heat transfer compound 92 805701 1 and new fuel pressure gauge adaptors to work with the GM L29 fuel rail fitting SB 98 4 Electric fuel pump check valve sticking Effects Cool Fuel models only Caused by new government mandated fuel detergent packages Net result is no fuel from the pump even though it is running SB 98 5 Gasoline additives causing fuel system component problems Effects all EFI mo dels Similar to 98 4 but includes injector problems and recommendations for preventing these problems SB 98 11 Required ECM replacement This effects 1998 7 4 MPI INBOARD models only 0L002006 0L007302 This does not effect stern drive models ECM recalibration to eliminate stalling when shifting into reverse gear PB 98 6 Rev 1 01 This is a PARTS bulletin concerning fuel system replacement parts VST top cover O ring is now available separately 25 803831 SB 97 20 Required fuel line replacement on Cool Fuel models This effects a massive number of 1997 and 1998 models The fuel lines m
155. nsor are used by the EFI system to identify abnormal conditions that affect engine operations If engine oil pressure drops too low or if drive unit fluid level in the reservoir bottle becomes too low or if the engine coolant temperature becomes too high the will engage the power reduc tion mode The power reduction mode allows normal fuel injection and full power up to 2 800 rpm Above 2800 rpm fuel delivery is limited to 1 injector TBI models or 4 injectors MPI models until rpm falls below 1200 The engine will then resume normal operation with all injectors firing If the problem goes away while power reduction mode is engaged the engine immediately resumes normal operation EFI System Air Delivery Components THROTTLE BODY MerCruiser EFI I The throttle body assembly is attached to the plenum and is used to control air flow into the engine The Throttle Position TP Sensor is mounted on the throttle body and is used for sensing throttle valve position The Idle Air Control IAC valve is also mounted on the throttle body and is used to control idle speed and to prevent engine stalls due to changes in engine load NOTE Later EFI systems have additional sensors which are covered in the service manuals 1003 EFI SYSTEM COMPONENTS OPERATION 2 27 Speed Density Theory and Operation Speed Density Theory All MerCruiser EFI engines operate on the fuel injection strategy called Speed Density This means that the
156. nstalled low pressure boost pump e Cast crankshaft p 496 Mag HO Bravo 1 2 or 3 425 pshp 4600 5000 rpm Direct replacement for 502 Mag e Same features as 496 Mag except forged crankshaft different cam and different PCM calibration from 496 Mag to achieve higher horsepower gt 8 15 Horizon standard Inboard 370 pshp 4200 4600 rpm Direct replacement for 454 Mag e Same features and base engine as 496 Mag MerCruiser EFI 1003 EFI PRODUCT HISTORY 1 13 gt 8 15 HO standard inboard 420 pshp 4400 4800 rpm e Direct replacement for 502 Mag e Same features and base engine as 496 Mag HO NOTE The 454 7 4L and 502 8 2L base engines are no longer available from GM These new models are replacements for these discontinued engines Service Notes e Refer back to all previous service notes e All engines except the 8 1 496 series use MEFI 3 ECMs The 8 1 496 series use the Mercury Marine PCM 555 controller often referred to as the Triple Nickel controller SB 2000 1 Alpha One models shift spring recall Incorrect spring causes delayed shift e SB 2000 5 Electric fuel pump recall Affects stainless steel pumps used on carbureted and cool fuel EFI MPI models in the mid to upper OL serial number range e SB 2000 9 6 2 MPI specifications e SB 2000 11 8 1 496 Mag specifications e SB 2000 12 Correct procedure for checking 8 1 496 oil level e SB 2000 13 496 cid 8 1L Exhaust Installat
157. ntake manifold vacuum line is attached to the regulator housing and a spring is mounted inside the housing pushing on the diaphragm Engine manifold vacuum and the spring counteract each other to apply the correct pressure in the regulator diaphragm under all engine oper ating conditions Fuel pressure varies from model to model When there is excess fuel in the cooler that cannot be used by the engine the fuel pressure regulator is forced open and the extra fuel is bled off and sent through a fuel line f back to the water separating fuel filter b WATER SEPARATING FUEL FILTER B Fuel not used by the engine is returned to the water separating fuel filter where it mixes with fuel com ing in from the fuel tank This fuel is then sent back to the engine This system does not require a return fuel line to the boat s fuel tank 2 70 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 EFI Cool Fuel System Fuel Flow Diagram MerCruiser EFI I 1003 a Fuel Line from boat s fuel tank b Water Separating Fuel Filter Electric Fuel Pump d Fuel Cooler e Fuel Pressure Regulator f Return Line to Fuel Filter g Water Flow through Cooler h Vacuum Line to Intake Manifold i Fuel Rail Fuel Injectors 8 k Dummy Regulator some MEFI 1 amp 2 models 74871R2 EFI SYSTEM COMPONENTS OPERATION 2 71 Cool aoe Exploded View Apply a thin even coating of Thermal Grease on
158. o 1 2 or 3 310 pshp 4200 4600 rpm 7 4 L MPI Inboard 310 pshp 4000 4400 rpm 454 Magnum Bravo 1 2 or 3 385 pshp 4600 5000 rpm 454 Magnum MPI Horizon Bravo 1 2 or 3 385 pshp 4600 5000 rpm 454 Magnum MPI Horizon Inboard 380 pshp 4400 4800 rpm 8 2 L MPI Inboard 400 pshp 4400 4800 rpm 502 Magnum Bravo 1 2 or 3 415 pshp 4600 5000 rpm VVVVVVVVVVVVVVVYV Model Line Changes from Recertification book Two new stern drive models 350 Magnum MPI Horizon Alpha Bravo 1 2 or 3 300 pshp 4600 5000 rpm 454 Magnum MPI Horizon Bravo 1 2 or 3 385 pshp 4600 5000 rpm p These engines are simply stern drive versions of the inboard Horizon models All engines use the 3 GM 99 Software ECM Service Notes Refer back to all previous service notes Misfire problem on Alpha EFI models using MEFI 1 GM 93 Software Temporarily by pass the shift interrupter switch with the Bravo jumper plug 805592A1 If problem goes away readjust or replace the switch The shift interrupt circuit opens the IC ignition con trol circuit causing a loss of spark as long as the circuit is open VST fuel system final filters need to be periodically cleaned or changed The top cover O ring is now available separately 25 803831 If the engine is equipped with a 55 or 90 amp block fuse on the starter motor the bolt and or nut going through the fuse may be loose and cause erratic running or los
159. oard 7 4L Inboard NOTE All BLACK wires with a ground symbol are interconnected within the EFI system harness NOTE Component position and orientation shown is arranged for visual clarity and ease of circuit identification 75993 1 Fuel Pump 13 Ignition System Relay 2 Distributor 14 Fuse 15 Amp Fuel Pump 3 Coil Fuse 15 Amp ECM DLC Battery EOM Injector Ignition 4 Gear Lube Monitor Bottle Not Used On MIE Fuse 10 Amp 5 Data Link Connector DLC Knock Module 6 Manifold Absolute Pressure MAP Sensor 15 Harness Connector To Starting Charging Harness 7 Knock Sensor 2 8 Idle Air Control IAC 16 Positive 4 Power Wire To Engine Circuit D Breaker R e Sensor S 17 Oil Pressure Audio Warning Switch Engine Coolant Temperature ECT Sensor 18 Load Anticipation Circuit Not Used On MCM 11 Electronic Control Module ECM i 12 Fuel Pump Relay 19 Intake Air Temperature IAT Sensor 2 22 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI 1003 MerCruiser EFI System Electronic Components see previous page for component location see part numbers 11 MerCruiser EFI I The ECM is the control center for the fuel injection system It constantly monitors information from various sensors engine temperature throttle opening engine speed air temperature and pressure and controls the systems that affect engine performance engine timing
160. oat s fuel line and fitting 1 Pipe Fitting in pipe thread at both ends 1 1 2 in 38 mm long 1 Tee Fitting in female pipe thread 1 Schrader Valve P N 22 805408 1 Cap Schrader Valve P N 22 805515 Tools required to measure fuel vacuum at fuel inlet of the engine 1 Digital Compound Gauge 30 in Hg to 99 9 psi that has an accuracy of within 296 of the reading Cole Parmer P N P 68950 00 Note 1 1 Gauge Guard 30 in Hg to 15 psi Cole Parmer P N U 07359 02 Note 1 1 Gauge Guard Liquid 4 fl oz Cole Parmer P N U 07359 50 Note 2 1 Hose connected to digital gauge with adaptor to connect to the Schrader valve Can use hose and Schrader valve connector from Fuel Pressure Kit P N 91 881833A 2 Tools required to measure fuel temperature at fuel inlet of the engine 1 DMT 2000 Meter P N 91 854009A 3 Reducer Bushing 1 4 in male to 1 8 in female pipe thread P N 22 48556 Temp Probe Compression Fitting 1 8 in pipe thread Cole Parmer P N H 08539 04 Temp Probe 4 in long with K connector Cole Parmer P N P 08117 45 Temp Probe Extension Cable 10 ft long with K connector Cole Parmer P N H 08516 30 Cole Parmer Instrument Company Phone 847 549 7600 or 800 323 4340 Fax 847 247 2929 International Fax 847 549 1700 NOTE 1 The Gauge Guard has to be used with the gauge listed to protect it from liquid gaso line or vapors Failure to use the Gauge Guard will damage
161. ogging mixture to the inlet of the Water Sep arating Fuel Filter IMPORTANT If the boat is out of the water follow instructions for running engine on flush device as found in service manual for the engine being fogged 12 Start and run engine as follows a Cool Fuel models Start and run engine at 1300 rpm for 5 minutes b VST models Start and run engine at 1300 rpm for 10 minutes 13 After specified running time is complete slowly return throttle to idle rpm and shut engine off IMPORTANT Do not run engine s fuel system dry of this fogging mixture in the 6 US gal 23 L remote outboard fuel tank 14 Clean flame arrestor and crankcase ventilation hoses and reinstall 15 Lubricate all items listed in Lubrication section 16 Drain seawater section of cooling system as outlined in Draining Instructions section 17 On Models with Closed Cooling System Test coolant to ensure that it will withstand the lowest temperature expected during storage 18 Service batteries per manufacturer s instructions 19 Clean outside of engine and repaint any areas required with Quicksilver Primer and Spray Paint After paint has dried spray Quicksilver Corrosion and Rust Preventive Type ll or wipe down with Quicksilver Storage Seal or SAE 20W engine oil 20 For sterndrive unit layup refer to appropriate sterndrive service manual NOTE For additional protection against freezing and rust to the exhaust manifolds and other componen
162. oints toward MPI models port side V8 7 4L 8 2L MEFI 1 MPI Cool Fuel MerCruiser MPI intake injectors All 7 4L amp 8 2L Yellow 36 248 860349A 1 Regulator on fuel cooler Black ring on hose MPI models Orange fitting Regulator on fuel rail does not control fuel pressure V8 7 4L 8 2L MEFI 3 MPI Cool Fuel MerCruiser MPI intake Magneti Marelli injectors All 7 4L amp 8 2L Blue 43 296 861126A 1 Regulator on fuel cooler Green ring on hose All 7 4L amp 8 2L fitting No regulator on the fuel rail V8 8 2L MEFI 3 MPI Cool Fuel MerCruiser MPI intake HP500 EFI Blue 43 296 861126 1 1999 UP Green ring on hose fitting Brown V8 8 2L MEFI 3 Dual TBI Cool Fuel Super Charger intake GM TBU HP575 SCi Pink 30 207 807952 1 2000 UP No ring on hose fitting MerCruiser EFI 0804 EFI SYSTEM COMPONENTS OPERATION 2 67 Multi Port Injection With Vapor Separator Tank VST 73895R2 a Fuel line from boat s fuel tank b Water separating fuel filter c Supply pump mechanical or electric d Vapor separator tank e Fuel rail f Fuel injectors 8 g Fuel pressure regulator h Vacuum line to intake manifold i Return line to vapor separator tank 2 68 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 Throttle Body Injection With Vapor Separator Tank VST MerCruiser EFI I 1003 7389581 Fuel line from boat s fuel tank b Water separating
163. ol Fuel System Fuel Pressure Regulators 2 65 Fuel Pressure Regulator Identification Revised 2 June 2003 2 66 Multi Port Injection With Vapor Separator Tank VST 2 68 Throttle Body Injection With Vapor Separator Tank VST 2 69 MerCruiser EFI 1003 pis EFI MPI System with Cool Fuel uel Delivery Components see diagram ON next ee 2 70 EFI MPI Cool Fuel System Fuel Flow Diagram 2 71 Cool Fuel System Exploded View 2 72 Cool Fuel System Water Separating Fuel Filter with Insulating Container 2 73 Cool Fuel Systems Diagrams 2 74 Multi Port Injection With Cool Fuel System 2 74 MerCruiser EFI 1003 Page 350 Magnum Multi Port Injection with 1 and MEFIZ2 2 75 350 Magnum Multi Port Injection with Ua 2 76 Throttle Body Injection With Cool Fuel SYSTEM 2 77 Fuel InJaclofS 2 78 Throttle Body Injection TBI Fuel Inie GIOI iudices RE RE RE EY ERR 2 78 Multi Port Injection MPI Fuel Injector 2 78 Fuel Injector Identification Revised Aug 6 2004 2 80 Gen Cool Fuel System 2 83 EFI SYSTEM COMPONENTS OPERATION 2 Abbreviations Crank Com oy DT E LC AM D D Digital Multimeter am
164. ols idle speed to a calibrated desired rpm based on sensor inputs and actual engine rpm The ECM uses four 4 circuits to move the Idle Air Control IAC valve The movement of the IAC valve varies the amount of air flow bypassing the throttle plates The ECM controls idle speed by determining the position of the IAC valve MerCruiser EFI I 1003 EFI SYSTEM COMPONENTS OPERATION 2 59 PCM 555 System Idle Air Control IAC Valve Operation NOTE ECM 555 System is similar The Throttle body has a 75mm bore with a 0 100 bypass hole for base models and a 0 200 bypass hole for HO high output models The air for the Idle Air Control IAC valve leaves the throttle body through a special adapter fitting and rubber hose The adapter fitting is installed where GM originally mounts their IAC motor The Idle Air Control IAC Valve is mounted on the rear of the intake manifold and is a Ford part mounted to a Mercury adapter It primarily controls idle speed by controlling the amount of air bypassing the throttle plates The air enters the IAC valve from the rubber hose con nected to the throttle body The air exits the valve and flows into cast passages in the intake manifold that were originally used by GM for the Exhaust Gas Re circulation EGR valve The IAC Valve is 2 wire actuator that is controlled by Pulse Width Modulation PWM The IAC Valve is normally closed and receives battery voltage from the Main Power Relay MPRLY The IAC valv
165. on signal lets the PCM know whether a cylinder is on compression stroke or on exhaust stroke so the PCM can inject fuel and fire the ignition coil on the appropriate stroke A failure of the Camshaft Position Sensor or its circuit will set a fault and will result in the PCM firing the ignition coils each revolution often called waste spark instead of every other revolution The fuel injectors will also operate in sequential mode where they all fire individually OIL PRESSURE SENSOR MerCruiser EFI I The Oil Pressure Sensor is a three wire sensor and is mounted just above the remote oil filter adapter on the port side of the crankcase It is a pressure transducer and its primary purpose is to supply oil pressure information to the Guardian program A failure in the Oil Pressure sensor or its circuit will set a fault 1003 EFI SYSTEM COMPONENTS OPERATION 2 25 SEA PUMP PRESSURE SENSOR The Sea Pump Pressure Sensor is also a three wire sensor and it is mounted in the sea pump body on the front starboard lower corner of the engine It is a pressure transducer and its primary purpose is to supply sea pump pressure information to the Guardian program A failure in the Sea Pump Pressure sensor or its circuit will set a fault OTHER COMPONENTS ASSOCIATED WITH THE ECM The provision for communicating with the is the Data Link Connector DLC 5 Con nector It is part of the EFI engine wiring harness and is electrically c
166. onnected to the ECM The codes stored in the ECM can be read through the DLC connector There are three fuses 14 located in a holder near the One 15 amp fuse is for the fuel pump and relay A 10 amp fuse for the ECM Injectors and a 15 amp fuse for the ECM Battery There are different modes of engine operation STARTING MODE With the ignition switch in the start position the ECM will turn on the fuel pump relay The elec tric fuel pump runs and pressurizes the fuel in the fuel rail The ECM then checks the Engine Coolant Temperature Sensor ECT and Throttle Position Sensor TP to determine the prop er air fuel ratio for starting The ECM controls the fuel delivered to the engine by changing the pulse width of the injectors RUNNING MODE When the engine is running the ECM checks the inputs from the following sensors to calculate the required air fuel ratio 1 Distributor Reference Signal for engine RPM 2 Manifold Absolute Pressure Sensor MAP 3 Intake Air Temperature Sensor IAT 4 Engine Coolant Temperature Sensor ECT Higher RPM or higher Manifold Absolute Pressure equals lower vacuum in the manifold or Lower Intake Air Temperature or Lower Engine Coolant Temperature signals the ECM to pro vide a richer fuel air ratio for the engine Lower RPM or lower Manifold Absolute Pressure equals higher vacuum in the manifold or higher Intake Air Temperature or higher Engine Coolant Temperature signals from these sen
167. p Tachometer Slave ECM Engine Control Module Switch Electronically Erasable Programmable Electronic Fuel Injection Throttle Position Sensor EMCT Exhaust Manifold Coolant Temperature EMI Electromagnetic Interference Vacuum x MerCruiser EFI 0804 EFI SYSTEM COMPONENTS OPERATION 234 1 amp 2 ECM Input and Sensor Descriptions The following lists the sensors switches and other inputs used by the ECM to control its vari ous systems Although we will not cover them all in great detail there will be a brief description of each LOS YS f dv System Relay Serial Data b Distributor For REF rpm k Audio Warning Buzzer c Discrete Switches Audio Warning Fuel Injectors d Knock Module m Motor e Knock Sensor n Ignition Control Module f TP o Fuel Pump Relay g MAP p Fuel Pump h ECT Inputs i r Outputs s ECM 2 2 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 32 3 Input and Sensor Descriptions KNOCK SENSOR 2 DISCRETE SWITCHES 7 4L AUDIO WARNING KNOCK SENSOR 1 LOAD SW SYSTEM DIST FOR RELAY REF RPM TP ECT IAT INPUTS ECM OUTPUTS IGNITION IAC FUEL CONTROL MOTOR INJECTORS AUDIO V REFERENCE WARNING 5 V OUTPUT BUZZER TO SENSORS SERIAL DATA DLC MerCruiser EFI I 1003 EFI SYSTEM COMPONENTS OPERATION 2 3 555 Input and Sensor Descriptions
168. p 4200 4600 rpm VST fuel system 8 2L MPI Bluewater Inboard 400 pshp 4400 4800 rpm VST fuel system gt 1996 1 2 models e 7 4LX EFI Bravo 1 2 or 3 300 pshp 4000 4800 rpm Cool Fuel system e 7 4L EFI Bluewater Inboard 310 pshp 4000 4800 rpm Cool Fuel system Six new small block models 5 7L EFI Alpha Bravo 1 2 or 3 220 pshp 4200 4600 rpm VST fuel system 2 bbl intake manifold 1 4 EFI PRODUCT HISTORY MerCruiser EFI 1003 j MerCruiser EFI 1003 350 Magnum MPI Gen Bravo 1 2 or 3 300 pshp 4600 5000 rpm VST fuel sys tem 1996 1 2 models gt 262 Magnum EFI Gen Alpha Bravo 2 or 3 205 pshp 4400 4800 rpm VST fuel system e Same GM throttle body injection and Delco EST ignition as previous 5 7 350 fuel injected models e All use the same standard electric fuel supply pump as carbureted models Oil pressure switch and starter solenoid control its operation gt 5 7 LX EFI Gen Alpha Bravo 1 2 or 3 280 pshp 4400 4800 rpm VST fuel sys tem p 350 Magnum EFI Gen Tournament Ski Inboard 290 pshp 4400 4800 rpm Cool Fuel System p Black Scorpion MPI Gen Inboard 315 pshp 4600 5000 rpm Cool Fuel Sys tem special inboard version with cooler on starboard side not modular like current system Special Fuel recommendation of 91 octane minimum for this engine only Unique plenum upper intake and single plate throttle body Uses same type
169. pm e Direct replacement for 7 4L MPI L29 p MX 6 2 Black Scorpion Ski Inboard 340 pshp 4800 5200 rpm e Constant tension hose clamps e Platinum spark plugs e S pipe exhaust e Flush system p 496 Mag Bravo 1 2 or 3 375 pshp 4400 4800 rpm e Direct replacement for 454 Mag e Uses Mercury Marine PCM 555 controller This is not engine Engine Guard ian is incremental power reduction based on the severity of the situation Power Trim Up limit goes through PCM 555 and a new relay e First SmartCraft capable MerCruiser Electric shift and throttle engines fly by wire are coming e Sequential multi port fuel injection e Distributorless ignition system Individual coil packs for each cylinder e idle air control is PWM pulse width modulation not IAC counts e Single point pneumatic drain system e Closed cooling standard block only not exhaust manifolds Factory filled with ex tended life anti freeze e Ceramic and EDP coated aluminum exhaust manifolds with temperature senders 1 sender for each manifold connected to the PCM 555 e Stainless steel tubular elbows with dry manifold joint e New power steering pump with remote reservoir e New water supply pump not standard Bravo pump with pressure sender e Same installation mount pattern as 454 502 e Slightly wider taller and longer than 454 502 e Firing order is 1 8 7 2 6 5 4 3 Uses standard Cool Fuel system with factory i
170. r easier service access This system will be standard on Small Block MPI V8 Bravo Small block MPI Inboard Big Block MPI Sterndrives and Big Block Inboards not available on V6 Sterndrive Small Block Alpha and Small Block Tow Sports e SB 2003 14 Service Repair of Electrical Test Equipment replaces Service Bulletin 97 13 e SB 2004 01 Electric Fuel Pump Troubleshooting e SB 2004 04 Computer Diagnostic System MerCruiser EFI 0804 EFI PRODUCT HISTORY 1 17 Multi Port Fuel Injection System Fuel Flow VAPOR SEPARATING TANK VST THROTTLE BODY FLAME ARRESTOR FUEL PRESSURE rus REGULATOR 2683 RETURN LINE HY INJECTORS Si z gt WATER SEPARATING FUEL FILTER ds 2 6 ED I FUEL PUMP SIGHT TUBE qo THROTTLE BODY i I MECHANICAL FUEL PUMP B SEAWATER PUMP hes P MerCruiser EFI 1003 EFI PRODUCT HISTORY 1 19 Early 350 Mag MPI Induction System 1 Nut 4 2 Flame Arrestor 3 Stud 4 4 Throttle Body 5 Manifold Absolute Pressure MAP Sens 6 Plenum 7 Screw 4 8 Fuel Line From Fuel Filter To Starboard Fuel Rail 9 Fuel Filter 10 Fuel Line From VST To Fuel Filter 11 Fuel Line From Starboard To Port Fuel Rail 12 Fuel Rail 2 13 Fuel Pressure Regulator 14 Fuel Block 15 Fuel Line From Fuel Block To VST 75068 16 Fuel Injector 8 17 Intake Manifold 18 Engine Coolant Temperature ECT Sensor 19
171. r the ECM can individually control the dwell charge time of each ignition event and the ignition timing to provide opti mum engine performance Feedback from the ignition coil helps the ECM and the coil driver determine the optimum time to charge the coil for maximum spark energy Base ignition timing is fixed and cannot be adjusted on this engine but the HVS must be indexed so that the spark is going to the correct cylinder at the correct time 555 controllers do not have cooling fins as found on MEFI controllers previously used on Mercruiser EFI MPI engines These fins are not necessary on ECM555 s as they utilize a low amperage coil driver circuit that does not generate as much heat as the MEFI control lers which have a higher amperage coil driver circuit The 555 uses its low current coil driver circuit to control a high current driver circuit located in a module adjacent to the coil NOTE There is a Camshaft position sensor in the HVS but Mercury is not using it Do not connect anything to the sensor in the HVS SPLICE 105 ex e lt emen PNK WHT em em em SPLICE 108 e e e WHT DK GRN BL WHT LT GRN SPLICE 104 gt BLK PNK w O P TAN BLK SPLICE 101 Q GRY d SPLICE 100 PNK WHTe eu eu eu eu O e 9 3 SPLICE 114 abt a Fuse Holder e CPS Connector b ECM 555 f 5 Volt Power c Ignition Coil g 5 Volt Ground d Ignition Coil Driver Mo
172. ration during cranking and when the engine starts running To help understand how EST circuits operate a relay with a double set of contact points is shown in the HEI module refer to the figures Distributor Module Mode and ECM Control Mode Solid state circuitry is used in the module but adding the relay makes it easier to visualize how EST functions During cranking the relay is in the de energized position see figure Distributor Module Mode This connects the pickup coil to the base of the transistor When the pickup coil applies a positive voltage to the transistor it turns ON When voltage is removed the transistor turns OFF When the transistor turns ON current flows through the primary winding of the ignition coil When it turns OFF the primary current stops and a spark is developed at the spark plug A small amount of advance is built into the EST module via a timing circuit in case the engine remains in the distributor module timing mode With the relay de energized a set of contacts shown closed would ground the EST IC line signal PICK UP COIL MODULE RELAY ADVANCE 8 ta Ne ignition Control Be Os p Dist Reference 59 HIGH p By Pass 5 7 Not Activated Dist Reference LOW Distributor Module Mode 2 34 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 EST Operation Engine Running Control Mode When the engine RPM reaches a predetermined value
173. rd out of the front case As you are looking at the circuit board selector facing you the 10 amp fuse is on the left side and the 2 amp is on the right e Q Can you check the fuses without taking the case apart A Yes To check the 10 amp fuse turn the selector to the temperature setting and use one test lead to bridge the common and temperature terminals The display should read close to room tempera ture To check the 2 amp fuse set the selector to the diode setting and bridge the common and Ohms terminals The display should read very close to zero Ohms if the 2 amp fuse is good e Q Does the DMT 2000A have Auto Power Off and Auto ranging A Yes The meter will shut off after approximately 30 minutes this is only a sleep mode there is still a power draw It is automatically in auto ranging The manual ranges can be selected using the Range button otherwise it is always in auto ranging e Q While using the Inductive RPM mode on small engines the display hunts or reads higher than actual RPM or even locks up the display What can be done A Use the RPM 1 signal conditioning module e Q Using the RPM mode the RPM s seem to be doubled why A On some late model ignition systems with a waste spark system the plug fires twice per cycle Simply switch to 2 Stroke to obtain the correct readings 3 4 DIAGNOSTICS MerCruiser EFI I 1003 e Q While using the Ohms range the display is not stable A Make sure
174. read ings may uncover the problem The scan tool has the ability to save time in diagnosis and prevent the replacement of good parts The key to using the scan tool successfully for diagnosis lies in the technician s ability to understand the system he is trying to diagnose as well as an understanding of the scan tool operation and limitations The technician should read the tool manufacturer s operating manual to become familiar with the tool s operation MerCruiser EFI 1003 General Service Precautions When Working On EFI Systems The following requirements must be observed 3 50 DIAGNOSTICS 1 2 3 Before removing any ECM system component disconnect the negative battery cable Never start the engine without the battery being solidly connected Never separate the battery from the on board electrical system while the engine is running Never separate the battery feed wire from the charging system while the engine is running 5 When charging the battery disconnect it from the boat s electrical system 10 11 Ensure that all cable harnesses are connected solidly and that battery connections are thoroughly clean Never connect or disconnect the wiring harness at the when the ignition is switched ON Before attempting any electric arc welding disconnect the battery leads and the ECM connector s When steam cleaning engines do not direct the steam cleaning nozzle at ECM system components If thi
175. replace the Keihin injectors Same Bosch connector MEFI 2 GM 96 Software ECM Additional features and codes are now enabled New software for the DDT and Rinda tools is required Alpha models now use a shift interrupt circuit in the ECM When pin J1 19 is opened from ground the ignition timing is retarded and the IAC counts are reduced to allow shifting When the switch is closed timing and IAC counts return to normal Bravo models require a jumper plug installed to keep this circuit grounded and the interrupt circuit disabled Scorpion 377 MPI Ski Inboard 360 pshp 4800 5200 rpm p Basically a stroked 3 75 in 350 GM to achieve 377 cubic inches p Same induction system as the Black Scorpion gt Cool Fuel System 30 psi fuel regulator p 93 software in a 2 case Two new big block models 7 4 L MPI Bravo 1 2 or 3 models 310 pshp 4200 4600 rpm and Inboard mod els 310 pshp 4000 4400 rpm p Uses the GM L29 base engine This engine was designed for torque not high rpm horsepower p GM multi port fuel injection system 75mm throttle body GM lower intake and plenum GM fuel injectors and rail GM fuel injector harness MerCruiser only adds elbow to turn throttle body to front of engine to allow water cooled exhaust manifolds to be installed This engine is basically a complete GM package p MEFI2 GM 96 Software ECM Additional features and codes are now enabled New
176. rol IC to maintain the calculated desired rpm This will make the tran sition from idle closed throttle to higher throttle settings smoother It will also help maintain constant low engine speeds from 700 to 1200 rpm At 5 or greater TP sensor setting the Moving Desired RPM mode is not active IMPORTANT An improperly adjusted throttle cable can cause the engine idle rpm to be higher than the normal 600 rpm even though the control throttle lever is back to the idle rpm position Load Anticipation Mode The Load Anticipation mode is used on MIE inboard and ski engines only The function is used to help inboard engines during shifting An electrical signal from the neutral safety switch on the transmission goes to the ECM on J2 20 This signal tells the ECM if the switch is closed or open In neutral gear the neutral safety switch is closed signal grounded When shifting into gear the switch opens signal open When the transmission is shifted into gear the open signal causes the ECM to add a cali brated amount of bypass air with the IAC This is done to increase the load handling capability of the engine when going into gear on larger boats When shifting back into neutral gear the additional IAC bypass air is removed in an attempt to limit engine rpm flares The amount of IAC air used is constantly monitored by the ECM After the transmission is shifted and the engine has stabilized the ECM calculates an error band from the Movi
177. rop in fuel rail pres sure that we can record and compare between each injector All injectors should have the same amount of pressure drop Injector testers are available for various manufacturers For 454 and 502 engines the tester must be capable of selecting an injector pulse width in the range of 200 400 milliseconds msec The recommended starting point for these engines is approximately 300 m sec In any case a pulse width that drops the fuel rail pressure to half the normal operating pressure should be used Engine cool down period ten minutes is necessary to avoid irregular readings due to heat soak fuel boiling Relieve fuel pressure in the fuel rail as outlined in Fuel Pressure Relief Procedure in Repair Procedures Remove plenum as outlined in Repair Procedures With ignition OFF connect fuel pressure gauge to fuel pressure tap Disconnect harness connectors at all injectors and connect injector tester to one injector Use adaptor harness furnished with injector tester to energize injectors Follow manufacturer s instructions for use of adaptor harness Ignition must be OFF at least ten seconds to complete ECM shutdown cycle Fuel pump should run about two seconds after ignition is turned ON At this point insert clear tubing attached to vent valve into a suitable container and bleed air from gauge and hose to ensure accurate gauge operation Repeat this step until all air is bled from gauge Turn ignition OFF for ten seco
178. ry cable use the 00 70mm gauge cable By using the same gauge battery cable 00 70mm gauge in the example above for BOTH the negative and positive cable the longer length positive cable can use a smaller gauge cable than it would have if the negative and positive gauges were sized to their respective lengths Battery Testing Hydrometer Tests A fully charged battery will read between 1 225 and 1 280 at 80 Fahrenheit Readings of 1 225 and lower will require recharging amp retesting All cells should read within 30 points of each other You must correct the Hydrometer reading for Ambient Temperature CAPACITY TESTS The Specific Gravity must be 1 225 or higher before continuing Variable Load High Rate Discharge Tester Recommended Discharge the battery with a load bank carbon pile set to 1 2 the CCA Rating or times the Rating for 15 Seconds at the end of the 15 second period the battery voltage must be 9 6 volts or higher Fixed Resistance This equipment has built in load for high rate discharge testing Follow equipment manufacturer s instructions regarding test period and meter readings Cranking Discharge Method With a Voltmeter attached to the battery Crank the engine for 15 seconds the battery voltage must be 9 6 Volts or higher at the end of the 15 second period Lower ambient temperature readings below 70 Fahrenheit will result in lower voltage rea
179. s specified below in the USA and Canada will operate satisfactorily when using a major brand of unleaded gasoline having a MINIMUM pump posted Octane Rating of 87 AKI anti knock index which is the average of the RON research octane number and the MON motor octane number Federal regulations mandate that you DO NOT use leaded gasoline in the USA and Canada Higher octane fuels can be used on all models with the exception of early EFI models On early EFI models refer to Service Bulletin 94 12 If these engines are equipped with the original ECM 87 AKI fuel must be used and higher octane fuels must NOT be used Early Black Scorpions Black Scorpions with serial number 0L0058999 and below must use fuel with a 91 AKI minimum Black Scorpions with serial number 0L0059000 and above can use fuel with a 87 AKI minimum Outside USA and Canada MerCruiser engines with the exception of the early Black Scorpions specified below outside the USA and Canada will operate satisfactorily when using a major brand of unleaded gasoline having a MINIMUM research octane number RON of 90 The use of leaded gasoline is acceptable unless prohibited by government regulations Higher octane fuels can be used on all models with the exception of early EFI models On early EFI models refer to Service Bulletin 94 12 If these engines are equipped with the original ECM 90 RON fuel must be used and higher octane fuels must NOT be used Early Black Scorp
180. s happens corrosion of the terminals or damage of components can take place Use only the test equipment specified in the diagnostic charts since other test equipment may either give incorrect results or damage good components All voltage measurements using a voltmeter require a digital voltmeter with a rating of 10 megohms input impedance MerCruiser EFI 1003 12 When a test light is specified a low power test light must be used DO NOT use high wattage test light While a particular brand of test light is not suggested a simple test as shown below on any test light will ensure it to be safe for system circuit testing Connect an accurate ammeter such as the high impedance digital multimeter in series with the test light being tested and power the test light ammeter circuit with the vehicle battery a Test Light b Battery IMPORTANT If the ammeter indicates LESS than 3 10 amp current flow 3 A or 300 mA the test light is SAFE to use If the ammeter indicates MORE than 3 10 amp current flow 3 A or 300 mA the test light is NOT SAFE to use NOTE Using a test light with 100 mA or less rating may show a faint glow when test actually states no light 13 When using a DVOM to perform voltage measurements turn the ignition OFF when con necting the DVOM to the circuitry to be tested MerCruiser EFI 1003 DIAGNOSTICS 3 51 Intermittent Faults IMPORTANT Problem may or may not turn ON th
181. s of engine rpm Tighten the screw and nut securely but do not overtighten EFI PRODUCT HISTORY 1 11 e The platinum spark plugs used in the Horizon series engines as follows 350 Magnum BPRSEFVX Long reach plug replaces AC MR43LTS 454 Magnum NGK BR6F VX Short reach plug replaces AC MR43T e f an EST ignition coil has melted check for a grounded tachometer lead in the engine harness boat harness or a defective tachometer Also check for any accessory wires con nected to the shop tach bullet connector on the engine e 3 big block stern drive is showing a General Diagnostic Trouble Code when starting the engine check for the trim and tilt sending unit leads incorrectly connected to the blue tan trans temp switch lead The trim sender leads must be connected to the brown white and black leads e SB 99 8 EFI MPI fuel pumps with low pressure Effects a large number of OL3XXXXX series engines Defective check valve in the Cool Fuel electric fuel pump causes fuel re striction above 4000 rpm Refer to bulletin for serial number groups and visual identifica tion of suspect pumps e SB 99 7 Rev 1 01 Gasoline engine vapor locking Tremendous amount of information on vapor lock its causes and remedies Also a list of tools to properly troubleshoot the fuel system e SB 97 24 revised Fuel pressure gauge adaptors fittings The L29 requires a larger test fitting than all other
182. shooting Flow Chart for MerCruiser EFI MPI Engines abbreviated A Diagnostic Trouble Code indicates that the has sensed that the circuit in question has re corded a sensor value outside of its acceptable window for at least as long as its pre programmed time period V The process begins with a Customer Complaint or when the technician notes an Observable Symptom The technician must Verify or Duplicate the complaint or symptom The technical must perform the OBD On Board Diagnostic check which consists of three major steps A Verify scan tool link up communication with ECM or code 12 on the winky blinky If not go to the appropriate chart in the service manual usually Chart A 1 and or A 2 B Verify that the engine will start If not go to the no start chart usually Chart A 3 Note that the engine does not have to run correctly it just must run C Check for Diagnostic Trouble Codes If codes are present fix active codes first lowest number code to highest number code then repair logged codes in same manner Locate the code in the table of contents of the appropriate service manual and section The section is usually called general system diagnostics or just diagnostics 1 When troubleshooting active codes the circuit in question is experiencing a failure right now You are looking for an open circuit or short circuit in the 2 or 3 wires involved with the sensor in question the sensor itself
183. should be 1 4 6 amp 7 and 2 3 5 amp 8 MEFI 3 and Audio Warning The MEFI 3 engine s Audio Warning system will sound the alarm differently and it has more items that will cause it to sound There is what is called a soft and a hard alarm 1 Soft Alarm Below 3000 rpm Horn on for 1 second off for 3 seconds on for 1 second off for 3 seconds etc 2 Hard Alarm Above 3000 rpm Horn sounds all the time Audio alarm sounds for the same malfunctions as MEFI 1 and 2 1 AMOM Low lube level in Gear Lube Bottle General 1 or MIE High Transmission fluid temperature General 2 2 MCM MIE Low engine oil pressure 3 MCM MIE Too high engine coolant temperature Early production and service ECMs had the following items that will sound the alarm 1 MCM MIE Horn will sound if there is an active engine Diagnostic Trouble Code DTC that is occurring while the engine is running The horn will not sound a stored DTC Correcting the DTC malfunction will stop the horn 2 MCM MIE Horn will sound if the battery voltage to the is low less than 9v for at least 5 seconds Using the throttle lever to increase engine rpm to get the alternator to put out more voltage will correct most low voltage problems V6 and V8 305 350 cid engines only Horn will sound if there is low fuel pressure for at least 5 seconds These engines have a fuel pressure sensor The EFI engines have the sensor
184. sible for proper engine operation 1003 EFI SYSTEM COMPONENTS OPERATION 2 17 555 Warning System Operation The engine warning system incorporates an audio alarm and if installed Smartcraft Gauges System When the key switch is turned to the ON position the audio alarm will momentarily activate to test the warning system The alarm should sound once if the system is operable This table is a guick guide showing what warning output will accompany a fault Smartcraft Audio Available Foun Gauges Power Desoripton ECTCKTHI Yes 2Bp min ECT CKT LO 2 Bp min 90 Short ECT Coolant Constant 100 Engine guardian overheat Overheat condition EST 1 EST 1Opent 1 Sere 2 Bp min 100 Coil harness wire open EST 1 Short Ys 2 Bp min 100 Coil harness wire short Pune 2 Bp min 10096 Fuel injector wire open ao o 2 100 Fuel injector wire open Guardian Strategy 0 100 Protection Strategy AC Output LOM 2 Low Drive Lube Yes Constant 100 Low oil in sterndrive Strategy Low Oil Pressure Yes Constant 0 100 Low oil pressure strategy Strategy NOTE If any 5v sensor becomes shorted to ground the engine will not start If the engine is operating when the short occurs the engine may stop operating and will not start NOTE GM EFI ignition system failure open or shorted driver will flag EST 1 fault NOTE 2 TPS must see 5 throttle then back to 0 to flag IAC faul
185. software for the DDT and Rinda tools is required p Requires a new fitting to accommodate the larger GM fuel rail test port See Service Bulletin 97 24 454 Magnum Horizon Inboard 380 pshp 4400 4800 rpm Basically a regular 454 Magnum with enhancements to increase durability and extend service intervals Most service intervals are now 3 years instead of 1 year Platinum spark plugs and hi temperature spark plug wires p Extensive use of EDP and ceramic coating Closed cooling standard with the new ex tended life antifreeze 5 years 1000 hours Constant tension hose clamps and engine mounted freshwater flushing device High mounted starter and alternator Stainless steel ground studs MEFI 1 GM 93 Software in a MEFI 2 case 1 8 EFI PRODUCT HISTORY MerCruiser EFI 1003 Service Notes Refer back to all previous service notes Only the 350 Magnum MPI and 7 4L MPI L29 engines use true 2 GM 96 software ECMs All others engines use the 2 GM 96 case but are loaded with 1 GM 93 software If an Alpha throttle body injected engine is stalling when shifting out of gear make sure the new shift interrupt spring 24 45599 1 has been installed If a 1998 7 4 L MPI L29 is whistling between 800 2000 rpm replace the throttle body gasket with 27 861518 This gasket has a D shaped hole in it and the words this side out printed on it The wro
186. stem is pressurized during operation Use care when removing water separating fuel filter Fuel could spray on hot engine caus ing fire or explosion Allow engine to cool down before attempting to remove the wa ter separating fuel filter in the following procedure Also hold a clean shop towel over the water separating fuel filter when removing it to help avoid fuel spraying on the engine If boat is in the water seacock water inlet valve if equipped must be closed until engine is to be restarted to prevent water from flowing back into cooling system and or boat If boat is not fitted with a seacock water inlet hose must be disconnected and plugged to prevent water from flowing back into cooling system and or boat As a precautionary measure attach a tag to the ignition switch or steering wheel of the boat with the warning that the seacock must be opened or the water inlet hose recon nected prior to starting engine DO NOT operate engine without water flowing through seawater pickup pump as pump impeller may be damaged and subsequent overheating damage to engine or sterndrive unit may result If engine is equipped with Closed Cooling System Closed Cooling section must be kept filled with a solution of ethylene glycol antifreeze and water mix antifreeze to manufacturer s recommended proportions to protect engine to lowest temperature to which it will be exposed DO NOT USE PROPYLENE GLYCOL antifreeze in closed cooling section
187. sure Switch gt WIRING 8 6 HARNESS 1 5 Instrumentation System SS 1 1 Trim Sender 2 Water Temperature Sender 3 Oil Pressure Sender C Charging and Starting System Starter Slave Solenoid Circuit Breaker Starter Ground Stud Alternator Oil Pressure Cut Off Switch Fuel Pump BRN WHT 10 NGO B ND a Harness Connector to EFI System Harness b Positive Power Wire to EFI System Harness c Auxiliary Tachometer Lead d 90 Amp Fuse DO NOT Remove 4 2 WIRING DIAGRAMS MerCruiser EFI I 1003 EFI System Harness Typical 1 TBI with VST Fuel System NYO LHM NY9 ikwa 74929 NOTE All BLACK wires with a ground symbol are interconnected within the EFI system harness 1 Vapor Separator Tank VST 12 Electronic Control Module ECM 2 Throttle Body 13 Fuel Pump Relay 3 Distributor 14 Ignition System Relay 4 Coil 15 Fuel Pump Fuse 5 Knock Sensor KS Module 16 ECM Ignition Feed KS Module Injectors Fuse 6 Data Link Connector DLC 17 ECM DLC Battery Fuse 7 Manifold Absolute Pressure MAP Sensor 18 Harness Connector To Starting Charging Har 8 Knock Sensor ness 9 Idle Air Control IAC 19 Shift Cutout Switch 10 Throttle Position TP Sensor 20 Lanyard Stop Switch 11 Engine Coolant Temperature Sensor ECT 21 Positive Power Wire To Engine Circuit Breaker MerCruiser EFI 1003 WIRING DIAGRAMS
188. t NOTE 3 2 wire sensor open will read sensor Hi on scan tool NOTE VDC PWR Low if shorted or no voltage engine will not start if VDC PWR voltage falls velow 22 volts will set sensor faults NOTE Shift Switch will activate code when engine rpm are above 3500 rpm and 40 load 2 18 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 555 Warning System Operation continued Smartcraft Audio Available s Engine will not start Engine will not start Main Power Relay Main Power Relay Backfeed MAP Sensor 1 Input High MAP Sensor 1 Input Low Oil PSI CKT Hi Oil PSI CKT Lo EM 2 Bp min High voltage or short Xe 28pmin s eue o Yes 2 Bp min Open defaults to 50 7 psi Yes 2 Bp min Short defaults to 50 7 psi Overspeed Yes Constant rpm limit Engine over rpm limit Pitot CKT Hi No 100 Short or high voltage he Yes 0 0 e s adi Strategy 2 Bp min Open 0 psi reading 2 Bp min Voltage high or short N N N Defaults to 31 degrees C N STB EMCT CKT Hi N N N A STB EMCT CKT Lo STB EMCT CKT N A N Overheat NOTE If any 5v sensor becomes shorted to ground the engine will not start If the engine is operating when the short occurs the engine may stop operating and will not start NOTE 1 GM EFI ignition system failure open or shorted driver will flag EST 1 fault NOTE 2 TPS must see 5 throttle then back to 0 to flag IAC fault NOTE 3 2 wire
189. t Normal Voltage Diag d Wire B ice Possible bor Color pa DTC s Master Lack Of Data From Other Engine BLK 451 WHT B None Incorrect Idle Poor Performance Discrete TAN J2 26 TP 417 DK 62V 62 21 Poor Performance And Accelera Signal BLU NOTE4 NOTE 4 tion Incorrect Idle _ Map LT 1 46V Poor Performance Surge Poor IAT Poor Fuel Economy Exhaust J2 32 191001 439 PNK B B None No Start Fused NOTE 1 Battery voltage for first two seconds then 0 volts NOTE 2 Varies with temperature NOTE 3 Varies with manifold vacuum NOTE 4 Varies with throttle movement NOTE 5 Less than 5 volt 500 mV 3 68 DIAGNOSTICS MerCruiser EFI 1003 NOTE This is a preliminary copy and it is subject to change Gen Cool Fuel Module Diagnostics Models Affected SemiNume Situation A new generation of the MerCruiser fuel cooling system has been developed and released into production The Generation Cool Fuel system incorporates many design elements The following information is provided for maintenance and troubleshooting of the Generation Cool Fuel Module Upon completion of these tests if problem exists replace the complete Cool Fuel Module assembly Changing Water Separating Fuel Filter Element Avoid Fire or Explosion The fuel injection system is pressurized during operation Use care when removing the water separating
190. tacts or housing due to improper engagement 3 Corrosion sealer or other contaminants on the contact mating surfaces 4 Incomplete mating of the connector halves during initial assembly or during subsequent troubleshooting procedures 5 Tendency for connectors to come apart due to vibration and or temperature cycling 6 Terminals not fully seated in the connector body 7 Inadequate terminal crimps to the wire Wire harnesses should be replaced with proper part number harnesses When signal wires are spliced into a harness use the same gauge wire with high temperature insulation only With the low current and voltage levels found in the system it is important that the best pos sible bond be made at all wire splices by soldering the splices as shown in the following il lustrations Use care when probing a connector or replacing connector terminals It is possible to short between opposite terminals If this happens certain components can be damaged Always use jumper wires with the corresponding mating terminals between connectors for circuit checking NEVER probe through connector seals wire insulation secondary ignition wires boots nipples or covers Microscopic damage or holes will result in eventual water intrusion corrosion and or compo nent or circuit failure NOTE Warranty repairs normally require the installation of a new harness 1 Locate damaged wire 2 Remove insulation as required 73048 3 Splice two
191. tage Adapter and Test Leads Attaching Alligator Clips PROCEDURE 1 Screw alligator clips over ends of probes with Red to Red and Black to Black Refer to Figure 1 4 Attaching Alligator Clips 2 Tighten alligator clips finger tight Figure 1 4 Attaching Alligator Clips MerCruiser EFI 1 1003 DIAGNOSTICS 3 9 Temperature Probe PROCEDURE 1 Plug small Thermocouple Plug into Thermo couple Probe with to and to refer to Figure 1 5 2 Plug Thermocouple Probe into DMT2000A with side to VOHz port refer to Figure 1 6 3 Position rotary function knob to TEMP position Use FUNCTION key to toggle between and F 4 Read temperature on DMT2000A Display Figure 1 5 Thermocouple Plug Figure 1 6 Thermocouple to Meter 3 10 DIAGNOSTICS MerCruiser EFI 1003 Clamp On Current Probe Optional Accessory P N 91 802650 IMPORTANT Refer to Users Guide supplied with Clamp On Current Probe for proper testing procedures PROCEDURE 1 Plug end of Clamp On Probe with side marked into VQHz port and side with to COM port refer to Figure 1 7 and Figure 1 8 Clamp On Probe to Meter 2 Position rotary function knob to DC Voltage scale indicated V DMT 2004 3 Read DC Voltage on DMT2000A Display 1 mV 1 amp Figure 1 7 Clamp On Probe ETA5018 AC DC CLAMP ADAPTER Figure 1 8 DMT2000A with Clamp On Current Probe
192. te and an EST Short will only register with the engine operating A malfunction in the coil harness will set the fault of EST 1 8 Open or EST 1 8 Short MerCruiser EFI I 1003 EFI SYSTEM COMPONENTS OPERATION 2 41 Manifold Absolute Pressure MAP Sensor Circuit NOTE circuit shown ECM PCM 555 circuits are similar On 555 System the MAP and MAT sensors are combined in one unit 75840 a Electrical Connector b Manifold Absolute Pressure MAP Sensor c Intake Manifold d Manifold Absolute Pressure Temperature Sensor MANIFOLD ABSOLUTE PRESSURE VACUUM CIRCUIT DESCRIPTION The Manifold Absolute Pressure MAP sensor responds to changes in manifold pressure vacuum The ECM receives this information as a signal voltage that will vary from about 1 0 2 0 volts at idle to about 4 0 5 0 volts at Wide Open Throttle WOT If the MAP sensor fails the ECM will substitute a default MAP value that will vary with rpm A reference voltage of 5 volts is provided to the MAP sensor through CKT 416 CKT 814 is the ground circuit for the MAP sensor MAP sensor CKT 432 will send a voltage signal to the proportional to the manifold pressure 2 42 EFI SYSTEM COMPONENTS OPERATION MerCruiser EFI I 1003 Ignition Control IC Circuit Source of Ref Hi signal in MEFI systems RSR ares or mal Ignition Module L 3 DISTRIBUTOR IGNITION RED cas 2 J
193. ted when battery voltage is below 9v at the ECM for at least 5 seconds and when fuel pressure is too low for 5 seconds on small block models only Refer to Service Bulletin 99 3 revised 12 99 for specific serial numbers and ECM checksum numbers these additional features are being disabled in current production engines The ECM incorporates an integral ignition module coil driver circuit This is only used on the small block V6 amp V8 models except Scorpion models A standard thunderbolt distributor and ignition coil are used but the ECM controls ignition coil dwell and timing This integral module is not used on big block models ECMs with GM part 1623999 will incorporate a Moving Desired Idle mode that operates between 0 and 5 Throttle plate opening This will allow more consistent speeds at part throttle operation since the ECM will attempt to maintain a steady rpm within this range Inboard applications have a Load Anticipation Mode Additional IAC counts are added when in either gear and are removed when in Neutral neutral safety type switch is connected to ECM J2 20 It is normally closed grounded in Neutral and is open ungrounded in either gear The MEFI 3 ECM incorporates Password protected EEPROM to prevent unauthorized reprogramming Footnotes 1 Except the 1998 350 Magnum MPI and the 129 7 4L MPI 2 If GM part number is any number other than 16210729 it is 1 software in a MEFI
194. the test leads are tight in the meter Also clean the probe ends with a mild abrasive for best contact e Q With the test leads touched together the display reads 0 3 Ohms A This is the actual value of the test lead resistance To zero the display for accurate low Ohms touch the leads together and depress the Rel button to zero e Q the Inductive RPM function how do set the number of cylinders It is not necessary when using this technique to measure RPM MerCruiser EFI 1003 DIAGNOSTICS 3 5 QUICKSILVER MARINE PARTS AND ACCESSORIES 91 854009A 3 DMT2000A Digital Tachometer Multi Meter Kit Instructions similar for a DMT 2004 version DMT 2004 Complete Kit P N 91 892647A01 DMT 2004 similar to DMT 2000A It has a serial port for connecting meter to a CDS unit 3 6 DIAGNOSTICS MerCruiser EFI 1003 Meter Connections and Hook up Interface Module Battery Check IMPORTANT The internal battery for the Interface Module P N 91 854013 1 MUST BE in good working condition to obtain stable tachometer readings A low battery voltage will give erratic readings PROCEDURE 1 Plug interface module into DMT2000A meter Refer to Figure 1 1 Red lead plugs into the VOHz port and the Black lead into the COM port 2 Position rotary function selector to DC Voltage V position 2004 VHz 3 Reading should be 2 8 Volts or higher 4 Replace interface module battery if reading is below 2 8 Volts
195. to the engine 17 Properly ventilate engine compartment Avoid serious injury or death due to FIRE or EXPLOSION Ensure that engine compartment is well ventilated and that no gasoline vapors are present to prevent the possibility of a FIRE or EXPLOSION Ensure that no fuel leaks exist before closing the engine hatch 18 Start the engine Check for gasoline leaks around the fuel filter assembly If leaks exist stop the engine immediately Recheck filter installation clean spilled fuel and properly ventilate engine compartment Correct the leak Disconnect electrical connector at Cool Fuel Module Connect Digital Volt Ohm Meter DVOM to engine side of electrical connector Turn ignition switch to run position Verify that there is 12 volt battery power going to the Cool Fuel Module SIN NOTE The fuel pump relay will only remain active for 2 3 seconds while the key is in the RUN position Checking Fuel Pressure MerCruiser EFI 0804 1 Connect fuel pressure gauge to shrader valve on fuel rail 2 Cycle key switch 2 3 times OFF to RUN position at 3 second intervals to reach maximum pressure 3 Verify that the pressure is within specification DIAGNOSTICS 3 85 4 f pressure is exceeds 44 psi a Replace Cool Fuel Module 5 f pressure is equal to or less than 40 psi a Use a tee fitting and connect a vacuum gauge to the fuel inlet side of the Cool Fuel Module Do not remove fuel inlet fi
196. tributor ignition coil and ECM No Spark With key switch in RUN position check if electric fuel pump is run ning Check for 12 volts at positive terminal on ignition coil Unplug distributor WHT RED bullet connector from the harness Check for 12 volts on lead coming from harness 12 Volts Reconnect distributor WHT RED bullet connector to harness Install a Spark Gap Tester from ignition coil tower to ground Crank engine over with key switch No spark at Coil Replace sensor on inside of distributor No spark at Coil Replace ignition coil 0 volts or fuel pump not running 0 Volts Check key switch battery engine and instrument wiring harness Check 10A fuse and lead Ignition system is good MerCruiser EFI 1003 Non Scan Diagnosis of Driveability Concerns With No Codes Set If a driveability concern still exists after following the diagnostic circuit check and reviewing Troubleshooting an out of range sensor may be suspected Because of the unique design of the EFI system fail safes have been incorporated into the ECM to replace a sensed value with a default value in the case of a sensor malfunction or sensor wiring concern By allowing this to occur limited engine performance is restored until the vessel is repaired A basic un derstanding of sensor operation is necessary in order to diagnose an out of range sensor If the sensor is within its working or acceptable param
197. ts a 50 50 mixture of antifreeze and water can be run through the engine during Power Package Layup 5 4 MAINTENANCE OFF SEASON STORAGE MerCruiser EFI 1003 GENERAL INFORMATION MerCruiser EFI 0804 Table of Contents Page Fuel Recommendations 6 1 Fuel Delivery System 6 3 Battery Requirements for MerCruiser Products 6 5 Battery Ratings 6 5 Cold Cranking Amps CCA 6 5 Marine Cranking Amps MCA 6 5 Reserve Capacity 6 5 Amp Hour Rating 6 5 Battery Cables Length and Size 6 7 Battery Testing 6 8 Hydrometer Tests 6 8 Charging Guide 6 9 12 Volt Battery Recommended Rate and Time for Fully Discharged Condition 6 9 Wiring Colors for MerCruiser 6 10 Wiring Harness Service 6 11 Wire Repair 6 11 Wiring Connector Service 6 12 6 1 GENERAL INFORMATION MerCruiser EFI I 1003 Fuel Recommendations IMPORTANT Use of improper gasoline can damage your engine seriously Engine damage resulting from use of improper gasoline is considered misuse of engine and damage caused thereby will not be covered under the limited warranty FUEL RATINGS USA and Canada MerCruiser engines with the exception of the early Black Scorpion
198. tting adapter b Cycle key switch 2 3 times OFF to RUN position at 3 second intervals to reach maximum pressure c Verify that the vacuum from the fuel source is within specification If vacuum is exceeds 2 Hg excessive fuel restriction exists Correct fuel restriction before proceeding d With vessel secured to the dock and engine running in neutral restrict fuel supply and verify that the Cool Fuel Module has the ability to cause a vacuum reading of 11 Hg or greater If vacuum reading is less than 11 Hg with fuel supply restricted replace Cool Fuel Module In Water Test 1 With vacuum gauge and fuel pressure gauges in place run the boat underway throughout the RPM range and record the pressure and vacuum readings 2 f fuel supply vacuum reading is greater than 2 Hg find and correct fuel supply restriction 3 Iffuel supply vacuumis within specification and fuel pressure is less than 40 psi replace Cool Fuel Module IMPORTANT It will be necessary to sea trial the boat following repairs to be sure that the pressure and fuel system vacuum remain within specification throughout the RPM range 3 86 DIAGNOSTICS MerCruiser EFI 0804 WIRING DIAGRAMS MerCruiser EFI 0804 Table of Contents Page Starting and Charging System Harness V6 Throttle Body Injection MEFI 1 with VST Fuel System 4 2 EFI System Harness Typical MEFI 1 TBI with VST Fuel Syste
199. ture Low Temperature Indicated IAT Intake Air Temperature High Temperature Indicated IAT Intake Air Temperature Low Temperature Indicated MAP Manifold Absolute Pressure Signal Voltage High MAP Manifold Absolute Pressure Signal Voltage Low IC Ignition Control Open IC Circuit ECM Calibration Memory Failure ECM EEPROM Failure MerCruiser EFI 1 1003 DIAGNOSTICS 3 59 3 Codes Code Connection Conditions Comments Number 14 ECT high Minimum run Ume 10 sec Open circuit Sensor output high cold 240 counts Faulty sensor h 15 ECT low Minimum run time 10 sec sensor Short circuit Sensor output low hot 7 counts Faulty sensor S high 250 ts i Open circuit ensor output high gt counts anytime 21 TPS high or skewed high gt 70 lt 700 rpm and lt WOT Faulty sensor 70 kpa for at least 5 seconds No reference ground Short circuit 22 TPS low Sensor output low lt 4 counts anytime rauy sengor No reference voltage 23 IAT high Minimum run ie 10 sec Open circuit Sensor output high cold gt 253 counts Faulty sensor F h 25 IAT low Minimum run time 10 sec sensor Short circuit Sensor output low hot 7 counts Faulty sensor Open circuit 33 MAP high kpa gt 80 and tps lt 5 and rpm gt 500 Faulty sensor at least 5 seconds No Reference ground Short circuit 34 MAP low kpa lt 14 and tps gt 5 and rpm 300 for at Faulty sensor least 0 5
200. tween each manifold and its elbow Both EMCT sensors are two wire sensors and their primary purpose is to tell the Guardian program the temperature of the coolant in each exhaust manifold Both EMCT sensors are thermistors and operate in the same manner as the ECT sensor A failure in either EMCT will set a specific fault for that sensor CRANKSHAFT POSITION SENSOR CPS The Crankshaft Position Sensor is a 3 wire Hall Effect sensor and is mounted on the rear of the engine on the port side The sensor extends all of the way down to a timing wheel permanently attached to the crankshaft Windows and vanes of the timing wheel pass near the sensor causing it to turn on and off The result is a square wave 5 Vdc signal sent back to the PCM This signal informs the PCM of crankshaft position and engine RPM The sensor s position is fixed and cannot be adjusted There is also no air gap adjustment on this sensor A failure of the Crankshaft Position Sensor or its circuit will not set a fault CAMSHAFT POSITION SENSOR CMP The Camshaft Position Sensor is another 3 wire Hall Effect sensor and is mounted on the timing cover at the front of the engine The sensor extends close to the camshaft gear which is specially machined to provide a single window and single vane that passes near the sensor causing it to turn on and off The result is a square wave 5 Vdc signal sent back to the PCM This signal informs the PCM of camshaft position The camshaft positi
201. ve decision center of the system It uses all the information it gathers to manage ignition spark delivering increased fuel economy and maximum engine performance The EFI system uses inputs from sensors to make decisions on the amount of spark advance or retard allowed The EFI system has been designed to control ignition advance and retard electronically by the ECM This electronic advance becomes much more exact and reliable just as EST is more exact and reliable when compared to the breaker point ignition system In order for the ECM to properly calculate spark advance it must always know at what speed the engine is running The engine speed signal is accomplished by a circuit within the EST module which converts the pickup coil voltage to a square wave digital reference signal that can be used by the ECM This square wave engine speed reference signal is known as REF HI The ECM must also have something to compare the REF HI value against Therefore an additional line is provided between the ECM and the EST module that is known as REF LO These two lines between the ECM and the distributor provide a precise indication of engine speed The two other lines between the ECM and distributor which control the Electronic Spark Timing EST operation are known as the bypass and IC Ignition Control circuits 1003 EFI SYSTEM COMPONENTS OPERATION 2 33 EST Operation Cranking Distributor Module Mode The following describes EST ope
202. w through cooler Vent line to flame arrestor i Throttle body with 2 fuel injectors dummy fuel pressure regulator 20 000 74871R1 EFI SYSTEM COMPONENTS OPERATION 2 77 Fuel Injectors The EFI injector assembly is a solenoid operated device controlled by the ECM that meters pressurized fuel to engine cylinders The ECM grounds the injector solenoid which opens a valve allowing fuel to flow past the valve The injector tip has holes that control the fuel flow generating a conical spray pattern of finely atomized fuel at the injector tip On throttle body systems fuel is directed into the bore of the Throttle Body Assembly and then it passes into the intake manifold On MPI models fuel is directed at the intake valve causing it to become further atomized and vaporized before entering the combustion chamber Throttle Body Injection TBI Fuel Injector 0o 50U0027375 772507 000099 2 78 Needle Valve Nozzle Cap O Ring Valve Stopper Core O Ring Spring Housing Solenoid Coil Tape Bobbin O Ring Inner Collar Sleeve Terminal Connector Filter O Ring ELECTRICAL TERMINALS SIDE VIEW SCREW POLE PIECE COIL i RETURN SPRING FUEL INLET SEAL RING RENT SPRAY TIP UPPER O RING FUEL INLET FILTER ELECTRICAL CONNECTION SOLENOID WINDINGS SPRING BALL amp SEAT VALVE DIRECTOR PLATE JIJ LOWER O RING 9 NU SPR
203. y and is located inside the meter at the bottom of the case inside e Q The DMT 2000A keeps using up batteries A The instrument has a sleep mode and not auto power off Since you may do long term recording there is still a battery draw on the system and it will go dead This is a normal condition and must be turned off manually each time e Q What sizes are the fuses and what are the part numbers A There are 2 fuses The small fuse is a 2 amp MT586 2 and the large fuse is a 10 amp MT586 3 e Q The display starts loosing segments and has unusual figures in cold weather what could be wrong A Check your operating temperature It s common for an LCD to freeze below 32 degrees F e The meter reads Ouch is it broken A No On Ohms the meter will reach Ouch to signify infinite Ohms On the temperature selection it means the thermocouple is not inserted or has an open circuit on the thermocouple Also when in the manual ranging mode the meter will read Ouch to indicate the range needs to be increased e Q The temperature reads Ouch and just replaced the thermocouple is there a field fix A Yes Since the temperature and mA range share the 2 amp fuse check for this fuse failure Also check for thermocouple continuity e Q What is the location of the fuses A The rubber boot should be removed and the 3 screws taken off the back cover Next split the case and remove the back cover Gently pry the circuit boa

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