Home

View/Print Brochure

1. SERVICE TOOL ITEM RICH LEAN Pre catalyst O2 A D counie Consistently gt 250 Consistently lt 170 Pre catalyst O2 sensor switching between high Always high ADC Always low ADC and low Trim valve duty cycle gt 90 lt 10 e Pre catalyst O2 e Pre catalyst O2 sensor failed rich sensor failed lean Malfunction codes e Pre catalyst O2 e Pre catalyst O2 sensor high sensor low e Fuel adapts e Fuel adapts Closed loop operation Stuck in open loop Stuck in open loop RICH OPERATION Gaseous fuel Trim valve duty cycle gt 90 e Check trim valve for proper operation replace as necessary e Check regulator out pressure replace if out of spec e Check natural gas composition LEAN OPERATION Gaseous fuel trim valve duty cycle lt 10 e Check for vacuum leaks replace hoses o rings and gaskets as necessary e Check balance line for blockage replace as necessary e Check vapor hose for restrictions replace as necessary e Check trim valve for proper operation replace as necessary e Check regulator out pressure replace if out of spec e Check natural gas composition Buck s Engines 56 Manual 36548 PG 08 Engine Control System for GM 8 1L Chart T 1 Restricted Exhaust System Check Proper diagnosis for a restricted exhaust system is essential before replacement of any components The following procedures may be used for diagnosis depending upon engine or tool used CHECK AT PRE CATALYST OXYGEN
2. Buck s Engines 36 Manual 36548 PG 08 Engine Control System for GM 8 1L WIRE HARNESS CONNECTOR Figure 17 Wire Harness Connector on Throttle Body D100 Mixer Installation Steps Refer to Figure 16 NOTE Replace the hose between the mixer adapter and the throttle body if it was damaged during removal 1 Install the trim valve 8 onto the mixer 4 2 Place a hose clamp 3 onto the hose that is on top of the throttle body 5 and insert the barbed end of the mixer 4 into the hose Tighten the hose clamp to 30 Ibf in 3 39 N m 3 Install the fuel line 2 to the trim valve inlet fitting 6 Install the vacuum line 1 to the mixer 5 Install the air cleaner hose gt Buck s Engines 37 Manual 36548 PG 08 Engine Control System for GM 8 1L Chapter 5 Tests and Adjustments SSS SSS EE EE EE Ee WARNING PROPER USE e Natural gas is highly flammable To prevent personal injury keep fire and flammable materials away from the lift truck when work is done on the fuel system Gas vapor may reduce oxygen available for breathing cause headache nausea dizziness and unconsciousness and lead to injury or death Always operate eduipment in a well ventilated area CAUTION The regulator and mixer are part of a certified system complying with EPA and CARB 2008 reduirements Only trained certified technicians should perform disassembly service or replacement of the regulator or mi
3. The PG 08 system utilizes two HEGO O2 sensors One sensor is a pre catalyst sensor that detects the amount of oxygen in the exhaust stream and is considered the primary control point Based upon the O2 sensor feedback the PG 08 system supplies a stoichiometric air fuel ratio to the catalytic converter The catalytic converter then reduces emissions to the required levels The second sensor is a post catalyst sensor that detects the amount of oxygen after the catalyst This sensor is used as a Secondary control point to adjust the pre catalyst setpoint to ensure proper catalyst conversion efficiency Once a HEGO sensor reaches approximately 600 F 316 C it becomes electrically active The concentration of oxygen in the exhaust stream determines the voltage produced If the engine is running rich little oxygen will be present in the exhaust and voltage output will be relatively high Conversely in a lean situation more oxygen will be present and a smaller electrical potential will be noticed Figure 10 HEGO 02 Sensor In order for the sensor to become active and create an electrical signal below 600 F 316 C a heated element is added to the sensor housing Two wires provide the necessary 12 Vdc and ground signal for the heater element A fourth wire provides an independent ground for the sensor The pre catalyst sensor heater is powered by the main power relay and is always powered The post catalyst sensor heater is powered fro
4. WARNING e Gas will be escaping from the test fitting in the test described above e Natural gas is highly flammable To prevent personal injury keep fire and flammable materials away from the lift truck when work is done on the fuel system Gas vapor may reduce oxygen available for breathing cause headache nausea dizziness and unconsciousness and lead to injury or death Always operate equipment in a well ventilated area Buck s Engines 39 Manual 36548 PG 08 Engine Control System for GM 8 1L Connection of PG 08 Service Tool To use the Service Tool a USB Universal Serial Bus to CAN Controller Area Network communication adapter by KVaser will be required along with a Crypt Token Figure 21 The Crypt Token acts as a security key allowing the laptop to retrieve the necessary data from the SECM 1 Install the Crypt Token in an available USB port in the computer Figure 22 With the ignition key in the OFF position connect the KVaser communication cable from a second USB port on the computer to the CAN communications cable on the engine f your laptop computer does not have a second USB port an appropriate USB hub will need to be used Connect a timing light to the engine Turn the ignition key to the ON position Do Not Start the Engine Launch the MotoView program on Pa your computer and open the Service Tool display Figure 23 Figure 21 KVaser Communication Adapter Figure 23 Open
5. 1024 Counts Input High Sensor Range z PERE a ae des ee ede Additionally the SECM includes software to learn the actual range of the pedal position and throttle position sensors in order to take full advantage of the sensor range Faults are set if the learned values are outside of the normal expected range of the sensor e g APP1AdaptLoMin Table 1 Fault List Definitions FAULT DESCRIPTION CODE Learned full pedal end of APP1AdaptHiMax APP1 sensor range higher 641 than expected Learned full pedal end of APP1AdaptHiMin APP1 sensor range lower 651 than expected Learned idle end of APP1 APP1AdaptLoMax sensor range higher than 661 expected Learned idle end of APP1 APP1AdaptLoMin sensor range lower than 631 expected APP1 sensor voltage out of range high normally set if the APP1RangeHigh APP1 signal has shorted to 621 power or the ground for the sensor has opened APP1 sensor voltage out of range low normally set if the APP1RangeLow APP1 signal has shorted to 611 ground circuit has opened or sensor has failed Learned full pedal end of APP2AdaptHiMax APP2 sensor range higher 642 than expected Buck s Engines 60 Manual 36548 PG 08 Engine Control System for GM 8 1L Table 1 Fault List Definitions cont d FAULT DESCRIPTION CODE APP2AdaptHiMin Learned full pedal value of APP sensor range lower than expected 652 APP2AdaptLoMax
6. LSeriesTrim L Series Trim Valve Fault The L Series trim valve has detected an internal fault 733 LowOilPressureFault Low engine oil pressure 521 MAPRangeHigh Manifold Absolute Pressure Sensor Input is High normally set if the TMAP pressure signal wire has become shorted to power shorted to the IAT signal the TMAP has failed or the SECM has failed 342 MAPRangeLow Manifold Absolute Pressure Sensor Input is Low normally set if the TMAP pressure signal wire has been disconnected or shorted to ground or the circuit has opened to the SECM 332 MAPTimeRangeHigh Manifold Absolute Pressure Sensor Input is High normally set if the TMAP pressure signal wire has become shorted to power shorted to the IAT signal the TMAP has failed or the SECM has failed 341 Buck s Engines Manual 36548 PG 08 Engine Control System for GM 8 1L Table 1 Fault List Definitions cont d FAULT DESCRIPTION CODE Manifold Absolute Pressure Sensor Input is Low normally set if the TMAP pressure signal wire has MESSE MERANER been disconnected or shorted to ground or the EN circuit has opened to the SECM MAP IR HI MAP sensor indicates higher pressure than 351 expected MAP IR LO MAP sensor indicates lower pressure than 352 expected MAP_STICKING MAP sensor not changing as expected 353 Engine speed has exceeded the s
7. Verify that no stored codes exist If emission test shows excessive CO and HC check items that cause engine to run rich If emission test shows excessive NOx check items that cause engine to run lean or too hot PROBABLE CAUSE Cooling system malfunction Fuel system malfunction Ignition system malfunction Component malfunction Related MIL Faults Low side driver Fuel adapt faults EST faults CORRECTIVE ACTION If the Service Tool indicates a very high coolant temperature and the system is running ean e Check engine coolant level e Check engine thermostat for faulty part always open or for wrong heat range e Check fan operation If the system is running rich refer to Diagnostic Aids chart on the next page If the system is running ean refer to Diagnostic Aids chart on the next page Check for properly installed fuel system components Check fuel pressure Check ignition timing Check spark plugs plug wires and ignition components Check for vacuum leaks Check for contamination in catalytic converter Check for carbon build up Remove carbon with quality engine cleaner Follow instructions on label Check for plugged PCV valve Check for stuck or blocked PCV hose Check for fuel in the crankcase Buck s Engines 55 Manual 36548 PG 08 Engine Control System for GM 8 1L Basic Troubleshooting cont d Diagnostic Aids for Rich Lean Operation
8. Buck s Engines 20 Manual 36548 PG 08 Engine Control System for GM 8 1L exhaust by modulating the FTV and adjusting the air fuel ratio This control scheme allows the SECM to make sure that the engine is running at the correct air to fuel ratio so that the catalyst can perform as required to meet the emissions certification Buck s Engines 21 Manual 36548 PG 08 Engine Control System for GM 8 1L SECM The Small Engine Control Module SECM controller has full authority over spark fuel and air Utilizing a Freescale micro controller the SECM has 48 pins of VO and is fully waterproof and shock hardened To optimize engine performance and drivability the SECM uses several sensors for closed loop feedback information These sensors are used by the SECM for closed loop control in three main categories e Fuel Management e Load Speed Management e Ignition Management The SECM monitors system parameters and stores any out of range conditions or malfunctions as faults in SECM memory Engine run hours are also stored in memory Stored fault codes can be displayed on the Malfunction Indicator Light MIL as flash codes or read by the PG 08 Service Tool software through a CAN Controller Area Network communication link Constant battery power 12 Vdc is supplied through the fuse block to the SECM and the main power relays Upon detecting a key switch ON input the SECM will fully power up and energize the main power rela
9. FAULT ACTION 1 TurnOnMIL 2 CutThrottle 1 TurnOnMIL 2 CutThrottle CORRECTIVE ACTION FIRST CHECK Check CAM sensor connections at distributor SECM SIGNAL Pin B10 to distributor connector Pin B SECM Sensor GND Pin B1 to distributor connector Pin A SECM 5V PWR to distributor connector Pin C Check for defective CAM sensor in distributor housing Check Crankshaft sensor connections SECM SIGNAL Pin B5 to Crank sensor Pin C SECM Sensor GND PIN B1 to Crank sensor Pin B SECM 5V PWR to Crank sensor Pin A Check for defective Crank sensor Check Crankshaft sensor connections SECM SIGNAL Pin B5 to Crank sensor Pin C SECM Sensor GND Pin B1 to Crank sensor Pin B SECM 5V PWR to Crank sensor PinA Check for defective Crank sensor Check throttle connector connection and TPS sensor for an open circuit or short to GND SECM Pin B23 signal to ETC Pin 6 SECM Pin B1 sensor GND to ETC Pin 2 SECM system GND Pin A16 B17 Check throttle connector connection and TPS sensor for an open circuit or short to GND SECM Pin B4 signal to ETC Pin 5 SECM Pin B1 sensor GND to ETC Pin 2 SECM system GND Pin A16 B17 68 Manual 36548 PG 08 Engine Control System for GM 8 1L Table 2 Diagnostic Fault Codes Flash Codes cont d TPS1RangeHigh TPS sensor voltage out of range high 1 TurnOn normally set if the MIL TPS signal has 2 Cut shorted to power or Throttle the ground for the sens
10. Learned idle value of APP sensor range higher than expected 662 APP2AdaptLoMin Learned idle value of APP sensor range lower than expected 632 APP2RangeHigh APP sensor voltage out of range high normally set if the APP signal has shorted to power or the ground for the sensor has opened 622 APP2RangeLow APP sensor voltage out of range low normally set if the APP signal has shorted to ground circuit has opened or sensor has failed 612 APP_Sensors_ Conflict APP position sensors do no not track well intermittent connections to APP or defective pedal assembly 691 CamEdgesFault No CAM signal when engine is known to be rotating broken CAM sensor leads or defective CAM sensor 191 CamSyncFault Loss of synchronization on the CAM sensor normally due to noise on the signal or an intermittent connection on the CAM sensor 192 CrankEdgesFault No crankshait signal when engine is known to be rotating broken crankshaft sensor leads or defective crank sensor 193 CrankSyncFault Loss of synchronization on the crankshaft sensor normally due to noise on the signal or an intermittent connection on the crankshaft sensor 194 ECTOverTempFault Engine Coolant Temperature is High The sensor has measured an excessive coolant temperature typically due to the engine overheating 161 ECTRangeHigh Engine Coolant Temperature Sensor Input i
11. PROBABLE CAUSE CORRECTIVE ACTION Fuel system Check for fuel leaks malfunction 7 nee Make sure power to system is shut off when key is in Ignition switching OFF position Fuel lock off valve Make sure lock off valve is closing properly Ignition system malfunction Check spark advance at idle Related MIL Faults EST faults ETC faults Pre catalyst O2 sensor faults Buck s Engines 49 Manual 36548 PG 08 Engine Control System for GM 8 1L Basic Troubleshooting cont d Rough Unstable Incorrect Idle or Stalling Engine cranks OK but does not start for a long time Does eventually run or may start but immediately dies PRELIMINARY CHECKS Perform the visual checks as described at start of Basic Troubleshooting chapter Check for vacuum leaks Check that SECM grounds are clean and tight See SECM wiring diagram PROBABLE CAUSE CORRECTIVE ACTION Monitor oxygen feedback to help identify the cause of the problem If the system is running lean or if the system is running rich evaluate further i e trim valve duty cycle Check for incorrect minimum idle speed that may be caused by foreign material accumulation in the Fuel system throttle bore on the throttle valve or on the throttle malfunction shatt The pre catalyst oxygen O2 sensor should respond quickly to different throttle positions If it does not then check the pre catalyst O2 sensor for contamination If the pre catalyst O2 sensor is aged or co
12. TPS SIGNAL 1 3K Q 30 TPS PIN 3 PWR to PIN 5 TPS2 SIGNAL 0 6K Q 30 Buck s Engines 69 Manual 36548 PROBABLE FAULT TPS1AdaptLoMax Learned closed throttle value of TPS sensor range higher than expected TPS2AdaptLoMax Learned closed throttle value of TPS sensor range higher than expected TPS Sensors Conflict TPS sensors differ by more than expected amount NOTE The TPS is not a serviceable item and can only be repaired by replacing the DV EV throttle assembly MAPTimeRangeLow Manifold Absolute Pressure sensor input is low normally set if the TMAP pressure signal wire has been disconnected or shorted to ground or the circuit has opened to the SECM Buck s Engines PG 08 Engine Control System for GM 8 1L Table 2 Diagnostic Fault Codes Flash Codes cont d 1 TurnOn MIL 2 Engine Shutdown TurnOnMIL CORRECTIVE ACTION FIRST CHECK Perform checks for DFCs 241 amp 242 Check TMAP connector and MAP signal wiring for an open circuit TMAP Pin 4 to SECM Pin B18 signal TMAP Pin 1 to SECM Pin B1 sensor GND TMAP Pin 3 to SECM Pin B24 PWR Check the MAP sensor by disconnecting the TMAP connector and measuring at the sensor TMAP Pin 1 GND to Pin 4 pressure signal kPa 2 4kQ 8 2kQ TMAP Pin 3 PWR to Pin 4 pressure signal kPa 3 4kQ 8 2kQ 70 Manual 36548 PROBABLE FAULT MAPRangeLow Manifold Absolute Pressure sensor input is
13. The throttle moves to its default position The engine will run at idle but will not accelerate Turn on MIL The MIL will light by an active low signal provided by the SECM indicating a fault condition May illuminate with no other action or may be combined with other actions depending on which fault is active Soft Rev Limit Medium Rev Limit Hard Rev Limit System will follow various sequences to bring engine speed back to acceptable levels Level4 Power Limit Level3 Power Limit Level2 Power Limit Level1 Power Limit The maximum engine power output will be limited to one of four possible levels The engine power is calculated from measured engine parameters e g MAP rpm fuel flow etc Disable Gas O2 Conirol In natural gas mode closed loop correction of air fuel ratio based on the Pre catalyst O2 sensor is disabled Buck s Engines 59 Manual 36548 PG 08 Engine Control System for GM 8 1L Fault List Definitions All the analog sensors in the PG 08 system have input sensor range faults These are the coolant temperature sensor fuel temperature sensor throttle position sensors pedal position sensors manifold pressure sensor HEGO sensors and intake air temperature sensor Signals to these sensors are converted into digital counts by the SECM A low high range sensor fault is normally set when the converted digital counts reach the minimum of 0 or the maximum of 1024 1024 5 0 Vdc with 204 counts per volt
14. low normally set if the TMAP pressure signal wire has been disconnected or shorted to ground or the circuit has opened to the SECM MAPTimeRangeHigh Manifold Absolute Pressure Sensor Input is High normally set if the TMAP pressure signal wire has become shorted to power shorted to the IAT signal the TMAP has failed or the SECM has failed MAPRangeHigh Manifold Absolute Pressure Sensor Input is High normally set if the TMAP pressure signal wire has become shorted to power shorted to the IAT signal the TMAP has failed or the SECM has failed Buck s Engines PG 08 Engine Control System for GM 8 1L Table 2 Diagnostic Fault Codes Flash Codes cont d FAULT ACTION TurnOnMIL TurnOnMIL TurnOnMIL CORRECTIVE ACTION FIRST CHECK Check TMAP connector and MAP signal wiring for an open circuit TMAP Pin 4 to SECM Pin B18 signal TMAP Pin 1 to SECM Pin B1 sensor GND TMAP Pin 3 to SECM Pin B24 PWR Check the MAP sensor by disconnecting the TMAP connector and measuring at the sensor TMAP Pin 1 GND to Pin 4 pressure signal kPa 2 4kQ 8 2kQ TMAP Pin 3 power to Pin 4 pressure signal kPa 3 4kQ 8 2kQ Check TMAP connector and MAP signal wiring for a shorted circuit TMAP Pin 4 to SECM Pin B18 signal TMAP Pin 1 to SECM Pin B1 sensor GND TMAP Pin 3 to SECM Pin B24 PWR Check the MAP sensor by disconnecting the TMAP connector and measuring at the sensor TMAP Pin 1 GND to Pin 4
15. natural gas in stationary industrial applications It provides accurate reliable and durable control of fuel spark and air over the service life of the engine in the extreme operating environment found in heavy duty under hood on engine electronic controls PG 08 is a closed loop system utilizing a catalytic converter to reduce the emission level in the exhaust gas In order to obtain maximum effect from the catalyst an accurate control of the air fuel ratio is required A small engine control module SECM uses two heated exhaust gas oxygen sensors HEGO in the exhaust system to monitor exhaust gas content One HEGO is installed in front of the catalytic converter and one is installed after the catalytic converter Od pressure Sensor Mardoid Pressure Temperature Sensor Figure 1 PG 08 System for GM 8 1L Natural Gas Engines The SECM makes any necessary corrections to the air fuel ratio by controlling the inlet fuel pressure to the air fuel mixer by controlling the position of the L Series fuel trim valve Closing the valve leans the air fuel mixture and opening the valve enriches the air fuel mixture To calculate any necessary corrections to the air fuel ratio the SECM uses a number of different sensors to gain information about the engine s performance Engine speed is monitored by the SECM through a Buck s Engines Manual 36548 PG 08 Engine Control System for GM 8 1L variable reluctance VR or Hall Effect sens
16. of the mixer This reduction in air pressure creates a pressure imbalance across the fuel metering orifices The fuel on one side of the orifices is at a higher pressure than the air on the other side and as a result fuel will flow across the orifices into the airstream The amount of fuel flow depends on the fuel pressure at the orifices and the size of the orifices The air fuel mixture then travels past the throttle through the intake manifold and into the engine cylinders where it is compressed ignited and burned Figure 5 D100 Mixer Attached to Throttle Body Buck s Engines 15 Manual 36548 PG 08 Engine Control System for GM 8 1L Electronic Throttle System PG 08 Electronic Throttle Conventional throttle systems rely on a mechanical linkage to control the throttle valve To meet fluctuating engine demands a conventional system will typically include a throttle valve actuator designed to readjust the throttle opening in response to engine demand together with an idle control actuator or idle air bypass valve In contrast the PG 08 system uses electronic throttle control ETC The SECM controls the throttle valve based on engine RPM engine load and information received from the speed input device The PG 08 system uses a Bosch electronic throttle body DV E5 in the following sizes a 32mm for 1 6L and 2 4L engines b 40mm for 3 0L and 4 3L engines c 60mm for 5 7L engines d 68mm for 8 1L engines The DV E5 is
17. pressure signal kPa 2 4kQ 8 2kQ TMAP Pin 3 power to Pin 4 pressure signal kPa 3 4kQ 8 2kQ Check TMAP connector and MAP signal wiring for a shorted circuit TMAP Pin 4 to SECM Pin B18 signal TMAP Pin 1 to SECM Pin B1 sensor GND TMAP Pin 3 to SECM Pin B24 PWR Check the MAP sensor by disconnecting the TMAP connector and measuring at the sensor TMAP Pin 1 GND to Pin 4 pressure signal kPa 2 4kQ 8 2kQ TMAP Pin 3 power to Pin 4 pressure signal kPa 3 4kQ 71 Manual 36548 FAULT ACTION MAP IR HI MAP sensor indicates TurnOnMIL higher pressure than expected MAP_IR_LO MAP sensor indicates TurnOnMIL lower pressure than expected MAP_STICKING MAP sensor not TurnOnMIL changing as expected IATRangeLow Intake Air Temperature Sensor Input is Low normally set if the IAT TurnOnMIL temperature sensor wire has shorted to chassis ground or the sensor has failed PROBABLE FAULT IATRangeHigh Intake Air Temperature Sensor Input is High normally set if the IAT TurnOnMIL temperature sensor wire has been disconnected or the circuit has opened to the SECM IAT_IR_Fault Intake Air NONE Temperature not changing as expected TurnOnMIL EST1_Open EST1 output open possibly open EST1 signal or defective spark module Buck s Engines PG 08 Engine Control System for GM 8 1L Table 2 Diagnostic Fault Codes Flash Codes cont d CORRECTIVE ACTION FIRST
18. 0 2 SENSOR Carefully remove pre catalyst oxygen O2 sensor 2 Install exhaust backpressure tester or equivalent in place of Op sensor using Snap On P N EEVPV311A kit and YA8661 adapter or Mac tool See Figure 26 3 After completing test described below be sure to coat threads of O2 sensor with anti seize compound prior to re installation f a N gt Ge ma i ly N 7 ILLUSTRATION NOTES 1 Backpressure gage 2 Pre catalyst Oxygen Os sensor 3 Exhaust manifold Courtesy of GM 1991 Service Manual for Chevrolet Camaro 1990 Figure 26 Installing Exhaust Backpressure Tester DIAGNOSIS 1 With the engine idling at normal operating temperature observe the exhaust system backpressure reading on the gage Reading should not exceed 1 25 psig 8 61 kPa 2 Increase engine speed to 2000 RPM and observe gage Reading should not exceed 3 psig 20 68 kPa 3 If the backpressure at either speed exceeds specification a restricted exhaust system is indicated 4 Inspect the entire exhaust system for a collapsed pipe heat distress or possible internal damage split welds or cracked pipe 5 If there are no obvious reasons for the excessive backpressure the catalytic converter is restricted and should be replaced using current recommended procedures Buck s Engines 57 Manual 36548 PG 08 Engine Control System for GM 8 1L Chapter 7 Advanced Diagnostics PG 08 systems are equipped with buil
19. 8 1L Fuel Trim Valve Inspection FTV e Visually inspect the fuel trim valves for abrasions or cracking Replace as necessary e Inspect the bore of the trim valve for obstructions and contamination Clean or replace as necessary Inspect Mixer Assembly e Inspect for blockages Clean or replace as necessary Inspect for Intake Leaks e Visually inspect the throttle body assembly and intake manifold for looseness and leaks Repair as necessary Inspect Throttle Assembly e Visually inspect the throttle assembly motor housing for coking cracks and missing cover retaining clips Repair and or replace as necessary NOTE Refer to Chapter 4 for procedures on removing the mixer and inspecting the throttle plate Gie king the TMAP Sensor Verify that the TMAP sensor is mounted tightly into the manifold or manifold adapter with no leakage e If the TMAP is found to be loose remove the TMAP retaining screw and the TMAP sensor from the manifold adapter e Visually inspect the TMAP O ring seal for damage Replace as necessary e Apply a thin coat of an approved silicon lubricant to the TMAP O ring seal e Re install the TMAP sensor into the manifold or manifold adapter and securely tighten the retaining screw Inspect Engine for Exhaust Leaks e Start the engine and allow it to reach operating temperatures e Perform visual inspection of exhaust system from the engine all the way to the tailpipe Any leaks even after the post ca
20. CHECK Check for vacuum leaks Check that TMAP sensor is mounted properly Possible defective TMAP sensor Possible defective TMAP sensor Check that TMAP sensor is mounted properly Possible defective TMAP sensor Check TMAP connector and IAT signal wiring for a shorted circuit TMAP Pin 2 to SECM Pin B12 signal TMAP Pin 1 to SECM Pin B1 sensor GND To check the IAT sensor of the TMAP disconnect the TMAP connector and measure the IAT resistance Resistance is approx 2400 ohms at room temperature Check TMAP connector and IAT signal wiring for a shorted circuit TMAP Pin 2 to SECM Pin B12 signal TMAP Pin 1 to SECM Pin B1 sensor GND To check the IAT sensor of the TMAP disconnect the TMAP connector and measure the IAT resistance Resistance is approx 2400 ohms at room temperature Check connections to TMAP sensor Check that TMAP sensor is properly mounted to manifold Check ignition module wiring and connector for open circuit SECM Pin A9 EST1 to ignition module Pin B Verify GND on ignition module Pin C Verify 12 Vdc on ignition module PinA Refer to application manual for specific engine details 72 Manual 36548 PG 08 Engine Control System for GM 8 1L Table 2 Diagnostic Fault Codes Flash Codes cont d FAULT CORRECTIVE ACTION DFC PROBABLE FAULT ACTION FIRST CHECK EST1_ Short EST1 output shorted high or low EST1 signal shorted to ground or power or defective spark modu
21. Excessive Exhaust Emissions or Odors ees sesse ee eek ee ee ee ee ee Re ee ee 55 Diagnostic Aids for Rich Lean Operation iese ee RA Re Re 56 Chart T 1 Restricted Exhaust System Check esse sesse esse ek ee ee ke 57 CHAPTER 7 ADVANCED DIAGNOSTICS uu ees ee ee esse sesse ee ee RR RR RR ERGE EER RR ER EE EE 58 Reading Diagnostic Fault Codes ese ke Re RA RA Re Re ke ee ee 58 Displaying and Clearing Fault Codes DFC from SECM Memory 58 Fault Action Descriptions ee ee ee Re Re ee ee Re ee ee 59 Fault List Definitions sesiis EE EE EE AN 60 Table 1 Fault List DefinitiONS esse ee ee ee RR AR Re ee ee ee ee ee 60 Table 2 Diagnostic Fault Codes Flash Codes ees ek Re ee 67 CHAPTER 8 PARTS DESCRIPTION 222 2ccccccccececennsneccccstensseensnnnccdeseeesesee 81 Fuel System Component icc ii KEER ese Ee Ged lieben eal 81 Maxitrol Z TODZ Regulator sis KERKE RE KEES VEER Eg EE We SE EE Bed EE Re Seg ERG SEE Reed Ese ek 82 Buck s Engines Manual 36548 PG 08 Engine Control System for GM 8 1L List of Figures Figure 1 PG 08 System for GM 8 1L Natural Gas EngineS sesse sesse seke ee ese 8 Figure 2 PG 08 Closed Loop NG Fuel System iese see eke ee ke RA Re ee 9 Figure 3 Maxitrol 210DZ RegulatoOr ee sees ee Re ee ee ee Re de ee ee 14 Figure 4 D100 MixeF sees ee ee Re ee ee aa ee ee ee ee ee 15 Figure 5 D100 Mixer Attached to Throttle Body ee ee eee ee ee 15 Figure 8 Bo
22. collapsed hose Check for vacuum leaks Between mixer and throttle body Vacuum leak Between throttle body and intake manifold Between intake manifold and cylinder head Related MIL Faults EST faults ETC Sticking fault Pre catalyst adapts error Buck s Engines Manual 36548 Cuts Out Misses PG 08 Engine Control System for GM 8 1L Basic Troubleshooting cont d Steady pulsation or jerking that follows engine speed usually more pronounced as engine load increases sometimes above 1500 rpm The exhaust has a steady spitting sound at idle or low speed PRELIMINARY CHECKS Perform the visual checks as described at start of Basic Troubleshooting chapter PROBABLE CAUSE Fuel system malfunction Ignition system malfunction Component malfunction Engine mechanical Related MIL Faults EST faults ETC Sticking fault CORRECTIVE ACTION Check fuel system specifically for plugged fuel filter low pressure Check for contaminated fuel Check lock off intermittent connection Check trim valve operation Check for spark on the suspected cylinder s using a shop oscilloscope or spark tester or equivalent If no spark check for intermittent operation or miss If there is a spark remove spark plug s in these cylinders and check for cracks wear improper gap burned electrodes heavy deposits Check spark plug wires by connecting ohmmeter to ends of each wire in question If meter reads over
23. commanded Can occur at all engine speeds Usually most severe when first applying a load to the engine May cause engine to stall PRELIMINARY CHECKS Perform the visual checks as described at start of Basic Troubleshooting chapter Operate engine verify problem exists Remove air filter and check for dirt or other means of plugging Replace if needed PROBABLE CAUSE CORRECTIVE ACTION Check for restricted fuel filter Check fuel supply Check for contaminated fuel Check for clogged fuel filter and repair or replace as required See Chapter 3 Fuel Filter replacement Check for plugged fuel line and remove any obstruction from the fuel line e Using caution disconnect the fuel line some natural gas may escape e Clear obstruction with compressed air Fuel system malfunction e Re connect fuel line Check for faulty vapor connection between pressure regulator and mixer e Verify that there are no holes in hose e Observe that clamps are tight e Look for kinked pinched and or collapsed hose Monitor pre catalyst O2 with Service Tool Check for proper pressure regulator operation See Chapter 5 Test and Adjustments Check for proper air fuel mixer operation Check spark advance for excessive retarded ignition timing Use Service Tool Check secondary voltage using an oscilloscope or a spark tester to check for a weak coil Check spark plug condition Check poor spark plug primary and secondary wire condition I
24. illuminated indicating a fault use pedal to recover fault code s Repair faults Engine Coolant Check coolant leve x TT Inspect coolant hoses and fittings for leaks cracks swelling or deterioration Engine Ignition Inspect battery for damage X and corroded cables Inspect ignition system EE EN EN T x ON Replace spark plugs Oo ON EN EN N xa ON Fuel Lock Off Filter Inspect lock off and fuel filter X for leaks Ensure lock off stops fuel flow when engine is off Buck s Engines 32 Manual 36548 PG 08 Engine Control System for GM 8 1L Maintenance Schedule cont d INTERVAL HOURS Every Every Every 1000 1500 2500 Hours or Hours or Hours or 6 months 9 months 1 year CHECK POINT Every 250 Every 500 Hours or 1 Hours or month 3 months Pressure Regulator Inspect pressure regulator vapor hose for deposit build up Clean or replace as necessary Inspect regulator assembly for fuel coolant leaks Fuel Trim Valve Inspect valve housing for wear cracks or deterioration Ensure valve seals in the closed position when the engine is off Replace FTV When indicated by MIL Carburetor Check airfiterindicator x EP Check for air leaks in the filter system Inspect air fuel valve mixer assembly for cracks loose X hoses and fittings Repair or replace as necessary Check for vacuum leaks in X the intake system including manifold adapter and mixer to throttle adapter Re
25. per minute at the specified suction conditions AFR Air fuel ratio BHP Brake horsepower BTU British Thermal Unit Bi Fuel Able to operate on either of two fuels CTS Coolant temperature sensor CNG Compressed natural gas Able to run simultaneously on two fuels e g diesel and natural gas Often this term is Dual Fuel incorrectly used to describe bi fuel operation Spark ignited engines are typically bi fuel while compression ignition engines are dual fuel ECM Engine control module FPP Foot pedal position FPV Fuel primer valve FTV Fuel trim valve GPM Gallons per minute of flow HEGO Heated exhaust gas oxygen sensor LAT Limited angle torque motor MAP Manifold absolute pressure MAT Manifold air temperature MIL Malfunction indicator lamp Manufacturer of record for emissions MOR ENAA certification on the engine NG Natural gas NSPS New Source Performance Standards effective in 2008 for stationary spark ignited engines OEM Original equipment manufacturer Relative fuel air ratio or percent of PHI stoichiometric fuel actual fuel air ratio stoichiometric fuel air ratio RPM Revolutions per minute SECM Small engine control module TMAP Temperature and manifold absolute pressure TPS Throttle position sensor VDC Voltage of direct current type VE Compressed natural gas WOT Wide open throttle Buck s Engines 83
26. position sensor to determine the ignition timing so timing adjustments cannot be made IGNITION SYSTEM COMPONENTS In acoil near plug ignition system crankshaft and camshaft position sensors generate a basic timing signal by reading notches on the crankshaft flywheel or harmonic balancer and camshaft The crank and cam sensor signals go to the small engine control module SECM where they are used to determine firing order and turn the individual ignition coils on and off The operation of the ignition system is essentially the same as any other ignition system The coil has a low primary resistance 0 4 to 0 6 ohms and steps up the primary system voltage from 12 volts to as much as 40 000 volts to produce a Buck s Engines 18 Manual 36548 PG 08 Engine Control System for GM 8 1L spark for the spark plug Resistor spark plugs are generally used to suppress electromagnetic interference EMI MISFIRES Common ignition system ailments include misfiring hard starting or a no start Spark plugs can still be fouled by oil or fuel deposits as well as pre ignition and detonation If the crankshaft or camshaft position sensors fail the loss of the basic timing signal will prevent the system from generating a spark and the engine will not start or run A failed driver circuit within the SECM will also prevent proper ignition system operation It is important to remember that ignition misfire can also be caused by other factors
27. result in the unnecessary replacement of good components CORRECTIVE ACTION Most intermittent problems are caused by faulty electrical connections or wiring Perform careful visual physical check for e Poor mating of the connector halves or terminal not fully seated in the connector body backed out Improperly formed or damaged terminal All connector terminals in problem circuit should be carefully reformed or replaced to insure proper contact tension Loose connections or broken wires Poor terminal to wire connection crimp If a visual physical check does not find the cause of the problem perform the following Run the engine with a voltmeter or Service tool connected to a suspected circuit Check if circuit is active and signal is reasonable Using the Service tool monitor the input signal to the SECM to help detect intermittent conditions An abnormal voltage or Service reading when the problem occurs indicates the problem may be in that circuit If the wiring and connectors check OK and a diagnostic code was stored for a circuit having a sensor check sensor An intermittent MIL light with no stored diagnostic code may be caused by e Ignition coil shortage to ground and arcing at spark plug wires or plugs e MIL light wire to ECM shorted to ground e SECM grounds refer to SECM wiring diagrams Check for improper installation of electrical options such as lights 2 way radios accessories etc EST wir
28. such as worn or fouled spark plugs loose or damaged coil connector or terminals low fuel pressure intake vacuum leaks loss of compression in a cylinder or even contaminated fuel These other possibilities should all be ruled out before coils are replaced A SECM controlled engine that cranks but fails to start in many cases will often have a problem in the crankshaft or camshaft position sensor circuits Loss of sensor signals may prevent the SECM from properly synchronizing thereby preventing the engine from starting and running IGNITION SYSTEM CHECKS The ignition coils can be tested with an ohmmeter Measure primary and secondary resistance and compare to specifications If resistance is out of specifications the coil is bad and needs to be replaced Also pay close attention to the tube that wraps around the spark plug Cracks can allow voltage to jump to ground causing a misfire The spark plug terminal should also fit tightly If a coil tests bad and is replaced cleaning the connector and wiring harness terminals of the coil can often avoid future problems Corrosion at either place can cause intermittent operation and loss of continuity which may contribute to component failure Applying dielectric grease to these connections can help prevent corrosion and assure a good electrical connection Buck s Engines 19 Manual 36548 PG 08 Engine Control System for GM 8 1L Exhaust System Heated Exhaust Gas Oxygen Sensors HEGO
29. 1 to ECT Pin B SECM System GND Pin A16 B17 Check regulator for coolant leaks Check for coolant system problems e g defective or stuck thermostat Check fuel select switch connection for a short to GND SECM SIGNAL Pin A12 SECM SIGNAL Pin A15 SECM Sensor GND Pin B1 Check CAM sensor connections at ECM SECM SIGNAL Pin B10 to distributor connector Pin B SECM Sensor GND Pin B1 to distributor connector Pin A SECM 5V PWR to distributor connector Pin C Check for defective CAM sensor in distributor housing 67 Manual 36548 PG 08 Engine Control System for GM 8 1L Table 2 Diagnostic Fault Codes Flash Codes cont d DFC PROBABLE FAULT CamSyncFault Loss of synchronization on the CAM sensor normally due to noise on the signal or an intermittent connection on the CAM sensor CrankEdgesFault No crankshaft signal when engine is known to be rotating broken crankshaft sensor leads or defective crank sensor CrankSyncFault Loss of synchronization on the crankshaft sensor normally due to noise on the signal or an intermittent connection on the crankshaft sensor TPS1RangeLow TPS sensor voltage out of range low normally set if the TPS signal has shorted to ground circuit has opened or sensor has failed TPS2RangeLow TPS sensor voltage out of range low normally set if the TPS signal has shorted to ground circuit has opened or sensor has failed Buck s Engines
30. 221 F 29 C to 105 C 20 F to 120 F 29 C to 49 C Due to the low vapor pressure of Natural Gas Fuel Temperature natural gas below 20 F 29 C repeated cranking to start the engine may be required Operating Voltage 8 16 Vdc 3 18 Vdc for less than 5 minutes E ED 24 Vdc for less than 1 minute 210DZ Pressure Regulator Specifications Fuel Supply Pressure 8 t5inH20 37 3 76 7 mbar Fuel Inlet Fitting 1 1 4 NPT Fuel Outlet Fitting 1 1 4 NPT Max Flow 110 lbm hr natural gas 1 0 0 2 inH O 100 2000 cubic feet per hour natural aas 2 49 0 498 mbar 0 25 0 1 inH O 100 2000 cubic feet per hour natural aas 2 49 0 498 mbar i Regulator tower must point upwards Mounting Should not be mounted on engine Buck s Engines 26 Fuel Outlet Pressure Setpoints Manual 36548 PG 08 Engine Control System for GM 8 1L D100 Mixer Specifications Fuel Natural Gas Fuel Inlet Fitting 3 4 NPT Air Intake Flange N A Mixer Mounting Flange N A Reference Pressure Ports 1 4 NPT port Fuel Inlet Adjustments None Idle Air Adjustment None Mounting Suitable for on engine mounting Electronic Throttle System Specifications Minimum Electrical Resistance of Throttle Actuator ee SECM Specifications Operating Temperature 20 F to 221 F 29 C to 105 C Long term Storage Temperature 40 F to 140 F 40 C to 60 C Short term Storage Temperature z A Hea
31. 30 000 ohms replace wire s Visually inspect wires for moisture dust cracks burns etc Spray plug wires with fine water mist to check for shorts Check engine ground wire for looseness or corrosion Check for electromagnetic interference EMI A missing condition can be caused by EMI on the reference circuit EMI can usually be detected by monitoring engine rpm with Service Tool A sudden increase in rom with little change in actual engine rpm indicates EMI is present If problem exists check routing of secondary wires and check ignition ground circuit Check intake and exhaust manifolds for casting flash or gasket leaks Perform compression check on questionable cylinders If compression is low repair as necessary Check base engine Remove rocker covers and check for bent pushrods worn rocker arms broken valve springs worn camshaft lobes and valve timing Repair as necessary Buck s Engines 52 Manual 36548 PG 08 Engine Control System for GM 8 1L Basic Troubleshooting cont d Poor Fuel Economy Excessive Fuel Consumption Natural Gas Exhaust Smell Fuel economy as measured during normal operation is noticeably lower than expected Also economy is noticeably lower than what it has been in the past PRELIMINARY CHECKS Perform the visual checks as described at start of Basic Troubleshooting chapter Verify operator complaint identify operating conditions Check typical operating conditio
32. L Table 2 Diagnostic Fault Codes Flash Codes ECTRangeLow Coolant Sensor DelayedEngine failure or shorted to Shutdown GND ECTRangeHigh Coolant sensor DelayedEngine disconnected or open Shutdown circuit ECTOverTempFault Engine coolant temperature is high The sensor has measured an DelayedEngine excessive coolant Shutdown temperature typically due to the engine overheating ECT_IR_Fault Engine coolant temperature not changing as expected FuelSelectConflict Conflict in fuel select signals normally set if both of the fuel select signals are shorted to ground CamEdgesFault No CAM signal when engine is known to be rotating broken crankshaft sensor leads or defective CAM sensor Buck s Engines FAULT CORRECTIVE ACTION DES PROBAELE FAHET ACTION FIRST CHECK NONE Signifies the end of one pass through the NONE fault list None used as end of the fault list identification Check ECT sensor connector and wiring for a short to GND SECM Signal Pin B15 To ECT Pin A SECM Sensor GND Pin B1 to ECT Pin B SECM System GND Pin A16 B17 Check if ECT sensor connector is disconnected or for an open ECT circuit SECM Signal Pin B15 to ECT PinA SECM Sensor GND Pin B1 to ECT Pin B Check coolant system for radiator blockage proper coolant level and for leaks in the system Possible ECT short to GND check ECT signal wiring SECM Signal Pin B15 to ECT PinA SECM Sensor GND Pin B
33. System for GM 8 1L ENGINE SPEED GOVERNING For idle speed control the idle speed is controlled by the SECM Unlike a mechanical system the idle speed is not adjustable by the end user The idle speed is adjusted by the SECM based on engine coolant temperature At the low engine speeds the SECM may use spark and throttle to maintain a constant speed regardless of load Ignition Management In the normal course of events with the engine operating at the correct temperature in defined conditions the SECM will use load and engine speed to derive the correct ignition timing In addition to load and speed there are other circumstances under which the SECM may need to vary the ignition timing such as start up and idle speed control SECM Sensors The 48 pin Small Engine Control Module SECM and sensors provide the computational power algorithm logic sensor inputs and control outputs to control the system The SECM receives signals from the sensors digitizes these signals and then through algorithms and calibration maps computes the desired output response to effect control of fuel spark and air to the engine The SECM also provides a variety of other functions and features These include system monitoring and diagnostics to aid in maintaining efficient system operation and auxiliary control SECM sensor inputs and control output specifications are specific to the application but include a selection of the following Analog I
34. a single unit assembly which includes the throttle valve throttle valve actuator DC motor and two throttle position sensors TPS The SECM calculates the correct throttle valve opening that corresponds to the engine s demand makes any adjustments needed for adaptation to the engine s current operating conditions and then generates a corresponding electrical driver signal to the throttle valve actuator Figure 8 Bosch Electronic Throttle Body Buck s Engines 16 Manual 36548 PG 08 Engine Control System for GM 8 1L The PG 08 system uses a dual TPS design TPS1 and TPS2 The SECM continuously checks and monitors all sensors and calculations that effect throttle valve position whenever the engine is running If any malfunctions are encountered the SECM s initial response is to revert to redundant sensors and calculated data If no redundant signal is available or calculated data cannot solve the malfunction the SECM will drive the system into one of its limp modes or shut the engine down storing the appropriate fault information in the SECM Throttle Plate Gear Drive DC Drive Motor Picture courtesy of Robert Bosch GmbH Figure 9 Throttle Body Assembly Exploded View Buck s Engines 17 Manual 36548 PG 08 Engine Control System for GM 8 1L Ignition System Spark ignited engines require accurate control of spark timing and spark energy for efficient combustion The PG 08 ignition system p
35. acceleration The engine makes sharp metallic knocks that change with throttle opening similar to the sound of hail striking a metal roof PRELIMINARY CHECKS Perform the visual checks as described at start of Basic Troubleshooting chapter PROBABLE CAUSE CORRECTIVE ACTION Check fuel pressure To determine if the condition is caused by a rich or lean system the engine should be run at the speed of the complaint Monitoring with the Service Tool will help identify problem Fuel system malfunction Check for obvious overheating problems Low engine coolant Loose water pump belt Restricted air flow to radiator or restricted water flow through radiator Inoperative electric cooling fan Correct coolant solution should be a mix of anti freeze coolant or equivalent and water High coolant temperature Ignition system Check ignition timing malfunction Check spark module wiring Check exhaust backpressure Check for debris clogging the catalyst Check that pre catalyst O2 sensor is functioning Cooling system malfunction Exhaust system malfunction Check for excessive oil in the combustion chamber and or blow by from excessive PCV flow Check combustion chambers for excessive carbon build up Check combustion chamber pressure by performing a compression test Check for incorrect basic engine parts such as cam heads pistons etc Engine mechanical Related MIL Faults EST faults Encoder error High c
36. an battery outer surfaces with a mixture of baking soda and water e Inspect battery outer surfaces for damage and replace as necessary e Remove battery cables and clean repair and or replace as necessary Inspect Ignition System e Remove and inspect the spark plugs Replace as required e Inspect the ignition coil for cracks and heat deterioration Replace as required Replace Spark Plugs Using a gentle twisting motion remove the high voltage leads from the spark plugs Replace any damaged leads e Remove the spark plugs e Gap the new spark plugs to the proper specifications e Apply anti seize compound to the spark plug threads and install e Re install the high voltage leads CAUTION Do not over tighten the spark plugs Testing Fuel Lock off Operation e Start engine e Locate the electrical connector for the fuel lock e Disconnect the electrical connector e The engine should run out of fuel and stop within a short period of time NOTE The length of time the engine runs on trapped fuel vapor increases with any increase in distance between the fuel lock off and the pressure regulator e Turn the ignition key switch off and re connect the fuel lock off connecior Pressure Regulator Inspection e Visually inspect the pressure regulator housing for cracks or abrasions e Refer to Chapter 4 if the pressure regulator requires replacement Buck s Engines 30 Manual 36548 PG 08 Engine Control System for GM
37. ate the relay to flow current through the post Oz heater Verify O2 sensor heater circuit is operating by measuring heater resistance 2 1Q 0 4Q O2 Pin C GND to Pin D power Check for vacuum leaks Check fuel trim valves e g leaking valve or hose Check for missing orifice s Correct other faults that may contribute to 752 e g faults pertaining to fuel trim valves Pre Cat O2 Post Cat O2 sensor Check for vacuum leaks Check for leaks in exhaust catalytic converter HEGO sensors repair leaks Check all sensor connections see fault 742 corrective actions Check fuel trim valves e g plugged valve or hose Check for plugged orifice s Buck s Engines 77 Manual 36548 Table 2 Diagnostic Fault Codes Flash Codes cont d FAULT DFC PROBABLE FA p BEL ACTION GasPostO2FailedRich Pre catalyst O2 sensor indicates extended rich operation on natural gas O2RangeLow Pre catalyst O2 sensor voltage out of range low sensor signal shorted to ground O2 PostCatRangeLow Post catalyst O2 sensor voltage out of range low sensor signal shorted to ground O2RangeHigh Pre catalyst O2 sensor voltage out of range high sensor signal shorted to power O2 PostCatRangeHigh Post catalyst O2 sensor voltage out of range low sensor signal shorted to ground Buck s Engines PG 08 Engine Control System for GM 8 1L 1 TurnOnMIL 2 DisableGasPost O2Ctrl 1 TurnOnMIL 2 DisableGasO2Ct
38. bstruction with compressed air e Re connect fuel line e Leak test p Repair replace as required Clogged tual iiet See Chapter 3 Fuel Filter replacement Check connection Faulty vapor connection e Verify no holes in hose between the pressure regulator e Clamps must be tight and the mixer e Look for kinked pinched and or collapsed hose Repair replace fuel lock off Fuel lock off malfunct See Chapter 3 Fuel Lock off Press e reg lator malfunction Test regulator operation and pressure 9 See Chapter 5 Tests and Adjustments Incorrect air fuel or ignition spark control No crankshaft position Verify the crankshaft position signal is present sensor signal See Chapter 7 Advanced Diagnostics continued on next page Plugged fuel line See Chapter 7 Advanced Diagnostics Buck s Engines 44 Manual 36548 PG 08 Engine Control System for GM 8 1L Basic Troubleshooting cont d Engine Cranking but Will Not Start Difficult to Start cont d PROBABLE CAUSE SECM control system malfunction Fuel system malfunction Ignition system malfunction Related MIL Faults CORRECTIVE ACTION Check Coolant Temperature Sensor using the Service Tool compare coolant temperature with ambient temperature on cold engine If coolant temperature reading is 5 greater than or less than ambient air temperature on a cold engine check resistance in coolant sensor circuit or sensor itself Compare CTS resistanc
39. ctive O sensor or defective FTV 741 GasPostO2FailedRich Post catalyst O sensor control on natural gas has reached rich limit and sensor still reads too lean This could be caused by oxygen leak before or just after sensor catalyst failure sensor failure or wiring relay failure causing the sensor to not be properly heated If any Pre O2 sensor faults are set diagnose these first and after correcting these faults recheck if this fault sets 712 GasPostO2FailedLean Post catalyst O2 sensor control on natural gas has reached lean limit and sensor still reads too rich This could be caused by catalyst failure sensor failure or wiring relay failure causing the sensor to not be properly heated If any Pre O sensor faults are set diagnose these first and after correcting these faults recheck if this fault sets 752 GasPostO2Inactive Post catalyst O sensor control on natural gas has sensed the O sensor is not responding as expected If any Pre O sensor faults are set diagnose these first and after correcting these faults recheck if this fault sets Possible causes for this fault are sensor disconnected sensor heater failed sensor element failed heater relay or SECM control of heater relay is disconnected or failed 742 HbridgeFault_ETC Electronic Throttle Control Driver has Failed Indeterminate fault on Hbridge driver for Electronic Throttle Control Possibly either ETC or ETC driv
40. e Storage Damage Negligence or Certain Modifications Buck s Engines is not responsible for repairs due to improper calibration of spark fuel and cooling systems misuse negligence accident alterations or applications not approved by Buck s Engines lack of performance of required maintenance services as recommended by Buck s Engines or improper installation or the failure to use fuel oil lubricants and coolant meeting Buck s Engines recommended specifications Performance of the required maintenance services and use of proper fuel oil lubricants and coolant are the responsibility of the owner See the Owner s Manual for full details Engine Removal and Reinstallation Reasonable labor costs Maximum of 4 Hours for Engine removal and reinstallation when necessary to make a warranty repair are covered by this warranty Maintenance Items This warranty does not cover the replacement of maintenance items such as oil spark plugs ignition points PCV valves and filters made in connection with normal maintenance service Limitations Incidental or Consequential Damages This warranty does not cover any economic loss including without limitation loss of use of the Engine or equipment costs of substitute or replacement equipment loss of time inconvenience or any other cost or expense resulting from a defect covered by this warranty Warranty Period The WARRANTY PERIOD begins on the date the Engine is delivered to the first
41. e value to Diagnostic Aids chart at end of this section Verify that there is no code for ETC spring check fault Check for 0 APP during cranking Cycle key ON and OFF and listen for throttle check movement on key OFF Check for oil pressure switch faults Check for sensor sticking faults Check TPS for stuck binding or a high TPS voltage with the throttle closed Check fuel lock off actuator should turn ON for 2 seconds when ignition is turned ON Check fuel pressure Check for contaminated fuel Check lock off fuses visually inspect Check FTV system for proper operation Check for proper ignition voltage output with spark tester Check spark plugs Remove spark plugs check for wet plugs cracks wear improper gap burned electrodes or heavy deposits Repair or replace as necessary Check for Bare or shorted wires Loose ignition coil ground Pickup coil resistance and connections Where present ETC spring check ETC faults EST faults TPS conflict APP faults Encoder error MAP faults Oil pressure faults Buck s Engines 45 Manual 36548 PG 08 Engine Control System for GM 8 1L Basic Troubleshooting cont d Lack of Power Slow to Respond Poor High Speed Performance Hesitation During Acceleration Engine delivers less than expected power Little or no increase in speed when speed increase is commanded Momentary lack of response as an increase in speed is
42. ecautions to minimize or eliminate electrostatic discharges Follow these precautions when working with or near the control 1 Before doing maintenance on the electronic control discharge the static electricity on your body to ground by touching and holding a grounded metal object pipes cabinets equipment etc Avoid the build up of static electricity on your body by not wearing clothing made of synthetic materials Wear cotton or cotton blend materials as much as possible because these do not store static electric charges as much as synthetics Keep plastic vinyl and Styrofoam materials such as plastic or Styrofoam cups cup holders cigarette packages cellophane wrappers vinyl books or folders plastic bottles and plastic ash trays away from the control the modules and the work area as much as possible Buck s Engines Manual 36548 PG 08 Engine Control System for GM 8 1L Chapter 1 System Overview PG 08 General Description Buck s Engines emission certified PG 08 control system provides a complete fully integrated engine management system that helps OEMs and packagers comply with New Source Performance Standards NSPS proposed by the Environmental Protection Agency EPA These standards are effective in 2008 for stationary spark ignited engines The control system is applicable to naturally aspirated engines ranging in size from 1 6L to 8 1L 25 to 220 HP 18 64 to164 kW with up to 8 cylinders running on
43. econd level 2 of soei oneee 3 of overspeed protection Me f Pre catalyst O sensor voltage out of range high OeRangerigh sensor signal shorted to power sal Pre catalyst O2 sensor voltage out of range low SPELD sensor signal shorted to ground an Post catalyst Os sensor voltage out of range high O2_PostCatRangeHigh sensor signal shorted to voltage source 5V or 922 battery 02 PostCatRangeLow Post catalyst O sensor voltage out of range low 912 sensor signal shorted to ground SensVoltRangeHigh Sensor reference voltage XDRP too high 561 SensVoltRangeLow Sensor reference voltage XDRP too low 551 ServiceFault1 Service Interval 1 has been reached 991 ServiceFault2 Service Interval 2 has been reached 992 ServiceFault3 Service Interval 3 has been reached 993 4 Service Interval 4 has been reached time to Semler ale replace HEGO sensors SEE ServiceFault5 Service Interval 5 has been reached 995 Engine speed has exceeded first level EI 1 of 3 of overspeed protection SysVoltRangeHigh System voltage too high 541 SysVoltRangeLow System voltage too low 531 Buck s Engines 65 Manual 36548 PG 08 Engine Control System for GM 8 1L Table 1 Fault List Definitions cont d FAULT DESCRIPTION CODE TPS1AdaptHiMax Learned WOT value of TPS sensor range higher than expected 251 TPS1AdaptHiMin Learned WOT value of TPS sensor range lower than expected 271 TPS1AdaptLoMax Learned clo
44. elAdaptRangeHi In natural gas mode system had to adapt lean more than expected LSeriesTrim GasO2NotActive Pre catalyst Os sensor inactive on natural gas open Os sensor signal or heater leads defective O2 sensor Buck s Engines PG 08 Engine Control System for GM 8 1L Table 2 Diagnostic Fault Codes Flash Codes cont d FAULT PROBABLE FAULT ACTION TurnOnMIL TurnOnMIL 2 DisableGas a 3 DisableGas PostO2Ctrl 1 TurnOnMIL 2 DisableGas O2Ctrl 3 DisableGas PostO2Ctrl 1 TurnOnMIL 2 DisableGas O2Ctrl 3 DisableGas PostO2Ctrl 1 TurnOnMIL 2 DisableGas O2Ctrl 3 DisableGas PostO2Ctrl CORRECTIVE ACTION FIRST CHECK Check fuel lock off valve for an open wire or connector being disconnected or signal shorted to GND Lockoff Pin B signal to SECM Pin A11 Lockoff Pin A power to SECM DRVP Pin A23 Check CSV for an open coil by disconnecting the CSV connector and measuring the resistance 26Q 3Q Check MIL lamp for an open wire or short to GND Check for vacuum leaks Check fuel trim valves e g leaking valve or hose Check for missing orifice s Check fuel trim valves e g plugged valve or hose Check for plugged orifice s Inspect trim valve for damage Check wiring to trim valve Check connection between SECM and Trim valve Check that Pre catalyst O2 sensor connections are OK O signal Pin B to SECM Pin B13 Oz Pin C GND to SECM DRVG GND P
45. ensor GND Verify transducer power at the SECM with a multimeter SECM Pin B24 PWR to SECM Pin B1 sensor GND Verify transducer power at ETC with a multimeter ETC Pin 3 PWR to ETC Pin 2 sensor GND Verify transducer power to the foot pedal with a multimeter Measure transducer power at the TMAP connector with a multimeter TMAP Pin 3 PWR to TMAP Pin 1 sensor GND Verify transducer power at the SECM with a multimeter SECM Pin B24 PWR to SECM Pin B1 sensor GND Verify transducer power at ETC with a multimeter ETC Pin 3 PWR to ETC Pin 2 sensor GND Verify transducer power to the foot pedal with a multimeter Usually associated with additional ETC faults e Check for ETC Sticking or other ETC faults Verify if the lift truck was motored down a steep grade Usually associated with additional ETC faults e Check for ETC Sticking or other ETC faults Usually associated with additional ETC faults e Check for ETC Sticking or other ETC faults Check foot pedal connector e Check APP signal at SECM PIN B7 Buck s Engines 75 Manual 36548 LSDFault_LockOff Fuel lock off Valve Fault signal has opened or shorted to ground or power or defective Fuel lock off valve LSDFault_MIL Malfunction Indicator Lamp Fault signal has opened or shorted to ground or power or defective MIL lamp GasFuelAdaptRangeLo In natural gas mode system had to adapt rich more than expected GasFu
46. er signals have been shorted to ground 491 HardOverspeed Engine speed has exceeded the third level 3 of 3 of overspeed protection 571 Buck s Engines 63 Manual 36548 PG 08 Engine Control System for GM 8 1L Table 1 Fault List Definitions cont d FAULT DESCRIPTION CODE IATRangeHigh Intake Air Temperature Sensor Input is High normally set if the IAT temperature sensor wire has been disconnected the circuit has opened to the SECM or a short to Vbatt has occurred 381 IATRangeLow Intake Air Temperature Sensor Input is Low normally set if the IAT temperature sensor wire has shorted to chassis ground or the sensor has failed 371 IAT_IR_Fault Intake Air Temperature not changing as expected 391 LSDFault_CrankDisable Crank Disable Fault signal has opened or shorted to ground or power or defective crank disable relay 715 LSDFault_Dither1 Dither Valve 1 Fault signal has opened or shorted to ground or power or defective dither 1 valve 711 LSDFault_Dither2 Dither Valve 2 Fault signal has opened or shorted to ground or power or defective dither 2 valve 712 LSDFault_LockOff Fuel lock off Valve Fault signal has opened or shorted to ground or power or defective Fuel lock off valve 717 LSDFault_MIL Malfunction Indicator Lamp Fault signal has opened or shorted to ground or power or defective MIL lamp 718
47. es should be routed away from spark plug wires coils and generator Wires from SECM to ignition should have a good connection Buck s Engines 42 Manual 36548 PG 08 Engine Control System for GM 8 1L Basic Troubleshooting cont d Surges and or Stumbles Engine power varies under steady throttle Sounds like the engine speeds up and slows down with no change in the speed command PRELIMINARY CHECKS Perform the visual checks as described at start of Basic Troubleshooting chapter Be sure operator understands engine operation as explained in the operator manual PROBABLE CAUSE CORRECTIVE ACTION The fuel management should maintain a stoichiometric air fuel ratio under all steady state operating conditions following engine warmup Failure of the Pre catalyst O2 sensor should cause an O2 sensor fault that can be diagnosed with the MIL lamp or Service Tool NOTE To determine if the condition is caused by a rich or lean system the engine should be run at the speed of the complaint Monitoring pre catalyst O2 adapts or trim valve duty cycle will help Fuel system malfunction identify problem Check fuel supply while condition exists Oxygen sensor malfunction Check in line fuel filter Replace if dirty or plugged Check fuel pressure Check for proper ignition voltage output using spark tester Check spark plugs Remove spark plugs check for wet N plugs cracks wear improper gap Ignition system malfuncti
48. es through a lock off valve and is then regulated down to the appropriate pressure to supply the mixer The regulator controls the fuel pressure to the gas air mixer In some cases a primary regulator is required to bring the supply pressure down to 8 15 inH O before the PG 08 fuel pressure regulator stage L Series Fuel Trim Valve The key to meeting emissions requirements when operating on natural gas is the L Series trim valve in the fuel system The L Series fuel trim valve used in the PG 08 system is configured as a positioner and will go to a position that is commanded via a pulse width modulated signal The L Series trim valve controls fuel delivery by providing a restriction in the fuel line prior to entering the mixer The valve controls the restriction by moving to a commanded position based on feedback from the SECM SECM The Small Engine Control Module SECM controls the natural gas lock off solenoid valve and the FTV The lock off valve is energized when fueling with natural gas and the engine is turning FTV commands will be altered by the SECM in order to maintain a stoichiometric air fuel ratio Commands are based primarily on feedback from the exhaust gas oxygen sensor PG 08 Electric Fuel Lock Off The fuel lock off is a safety shutoff valve normally held closed by spring pressure which is operated by an electric solenoid and prevents fuel flow to the regulator when the engine is not in operation In the PG 08 design
49. evice may also be needed for safety as appropriate WARNING PROPER USE Any unauthorized modifications to or use of this equipment outside its specified mechanical electrical or other operating limits may cause personal injury and or property damage including damage to the equipment Any such unauthorized modifications i constitute misuse and or negligence within the meaning of the product warranty thereby excluding warranty coverage for any resulting damage and ii invalidate product certifications or listings CAUTION POSSIBLE DAMAGE TO EQUIPMENT OR PROPERTY CAUTION BATTERY CHARGING To prevent damage to a control system that uses an alternator or battery charging device make sure the charging device is turned off before disconnecting the battery from the system CAUTION ELECTROSTATIC DISCHARGE Electronic controls contain static sensitive parts Observe the following precautions to prevent damage to these parts Discharge body static before handling the control with power to the control turned off contact a grounded surface and maintain contact while handling the control Avoid all plastic vinyl and Styrofoam except antistatic versions around printed circuit boards Do not touch the components or conductors on a printed circuit board with your hands or with conductive devices IMPORTANT DEFINITIONS A WARNING indicates a potentially hazardous situation which if not avoided could result in death or serious inj
50. fications iese Re Re RA ke RA Re Re eke ee ee 28 Chapter 3 Recommended Maintenance ee ke RA AA Re ee 29 Maintenance Tests amp InspectiOnS ee ee Re Re Re ee Re de bee 29 Test Fuel System for Leaks iese ee ke Re AA Re ee Re Re ee 29 Inspect Engine for Fluid Leaks sees ee ee ee Re ee Re ee ee Re ee ee 29 Inspect Vacuum Lines and FittiNGS sees ee ee ee Re Re ee ee 29 Inspect Electrical System sesse esse ek Re Re ek ee RA Re Re Re ee ee ee 29 Inspect Coolant HoseS iii sees esse dee ee ek ke ee ee ee ee Re ek ee ee de 30 Inspect Battery System ees dee ee Re Re Re ek ee ee Re ee ee 30 Inspect lgnition System ees ee ke aniani aaga ee 30 Replace Spark PIUS issaraen eiei DEEG Skaak SE ee Es de 30 Testing Fuel Lock off Operation ie ee ee RA Re Re Re Re ee 30 Pressure Regulator Inspection ee ee Re RA ee Re ee 30 Fuel Trim Valve Inspection FTV ese Re Re ee ee Re ee ee 31 Inspect Mixer Assembly see ee ee ee ee AR Ee ee ee Re ee AR Re ee ee 31 Inspect for Intake Leaks see ee ee ee ee AE Ge ee AE Ge ee ee iaa 31 Inspect Throttle Assembly ese ee ee Re ee AR Ge ee AE Re ee Ke ee ee Ee ee ee 31 Buck s Engines Manual 36548 PG 08 Engine Control System for GM 8 1L Checking the TMAP Sensor cccccecesceeseseeeeeeeeeeaeeeeaeeeeaeeeseaeeseneeseaeeeeaas 31 Inspect Engine for Exhaust Leaks iese ese esse eed eek ee ee ee ee ee ee ee ek ee ee ee 31 Maintenance Sc
51. gnition system malfunction continued on next page Buck s Engines 46 Manual 36548 PG 08 Engine Control System for GM 8 1L Basic Troubleshooting cont d Lack of Power Slow to Respond Poor High Speed Performance Hesitation During Acceleration cont d PROBABLE CAUSE CORRECTIVE ACTION Check SECM grounds for cleanliness and secure connection See SECM wiring diagrams Check alternator output voltage Repair if less than 9 volts or more than 16 volts Check for clogged air filter and clean or replace as required Check exhaust system for possible restriction Refer to Chart T 1 on later pages Inspect exhaust system for damaged or collapsed pipes e Inspect muffler for heat distress or possible internal failure Check for possible plugged catalytic converter by comparing exhaust system backpressure on each side at engine Check backpressure by removing Pre catalyst O2 sensor and measuring backpressure with a gauge Component malfunction See Engine Manufacturer s Service Manual Engine mechanical Check engine valve timing and compression Check engine for correct or worn camshaft Related MIL Faults EST faults ETC faults ETC spring check TPS faults APP faults Encoder error Delayed Shutdown faults Buck s Engines 47 Manual 36548 PG 08 Engine Control System for GM 8 1L Basic Troubleshooting cont d Detonation Spark Knock A mild to severe ping usually worse under
52. h the MIL lamp it is possible to generate a string of flashing codes that correspond to the fault type These diagnostics are generated only when the engine is not running and the operator initiates a diagnostic request sequence such as repeated actuations of the pedal within a short period of time following reset Service Tool A scan tool monitoring device is available to monitor system operation and assist in diagnosis of system faults This device monitors all sensor inputs control outputs and diagnostic functions in sufficient detail through a single access point to the SECM to allow a qualified service technician to maintain the system This MotoService software licensed by MotoTron Corporation is secure and requires a crypt token USB device to allow access to information NOTE It is the responsibility of the customer to consult with Buck s Engines regarding the selection or specification of any components that impact emissions performance or durability Buck s Engines Manual 36548 PG 08 Engine Control System for GM 8 1L Natural Gas Fuel System Operation The principles outlined below describe the operation of PG 08 on a natural gas fuel system A natural gas fuel system consists of the following components e Fuel filter supplied by customer e Electric fuel vapor lock off solenoid valve e Fuel pressure regulator e Twin orifice fuel trim valves e Gas air mixer e Miscellaneous hoses and fittings Fuel pass
53. hedule iek RA RR RA Re Re ee RA ee RA 32 CHAPTER 4 INSTALLATION PROCEDURES esse sesse ee ee ee ee ee RR ERG e ee ee ee ee EE 34 Removal and Installation of 210DZ RegulatoF ees ee Re ee 35 Removal and Installation of D100 MixeF see RA ee RA ee ee 36 CHAPTER 5 TESTS AND ADJUSTMENTS esse ee ee esse esse ee ee ee ee ee RR Ee e ee ee ee ee EE 38 210DZ Regulator Service Testing see ke Re RA Re Re Re Re ee 38 Connection of PG 08 Service Tool RR RA Re Re Re Re ee 40 Chapter 6 Basic Troubleshooting i iese ke Re RA Re Re Re ee ee 41 Preliminary CneckS i iese ss EE ERK eN ede ee ED Ee ek ae Se el ee a aa Aaaa 41 Basic TroubteshootiNg sensos ARAE aE REEE SAREAK A 42 da nel EE EO N OE AO OR EE OR 42 Surges and or StumbleS iese ek AR RA RA Re Re ke Re ee 43 Engine Cranking but Will Not Start Difficult to Start sesse eke eke 44 Lack of Power Slow to Respond Poor High Speed Performance Hesitation During AcceleratiON ees ee ee Re ee ee ee 46 Detonation Spark KNOCK i ee ke RA AA RA Re ee Re ke ee Re ee 48 Backfile es esses RA EK N EE S 49 RIES ae RUMOM EO RE NE Eaa OE N 49 Rough Unstable Incorrect Idle or Stalling i ees ee RA Re 50 Cuts Out MISSES ese ER ER RE RR Re ee ee ee ee ee ee ee ee ee ee ee ee 52 Poor Fuel Economy Excessive Fuel Consumption Natural Gas Exhaust ol RE ER RE EN 53 Highildle Speed ii EE SE WED DEE EER Se BE GEE neues Dee oe RES Ge Ee ge Ee 54
54. in ON This signals the operator that a fault has been detected by the SECM 2 Determine that there are no diagnostic codes stored or there is a diagnostic code but no MIL light VISUAL PHYSICALCHECK Several of the procedures call for a Careful Visual Physical Check which should include e SECM grounds for being clean and tight e Vacuum hoses for splits kinks and proper connection e Air leaks at throttle body mounting and intake manifold e Exhaust system leaks e Ignition wires for cracking hardness proper routing and carbon tracking e Wiring for pinches and cuts Also check e Connections to determine that none are loose cracked or missing e Fuel pressure is sufficient e Fuel is not leaking e Battery voltage is greater than 11 5 volts NOTE The Visual Physical check is very important as it can often correct a problem without further troubleshooting and save valuable time Buck s Engines 41 Manual 36548 PG 08 Engine Control System for GM 8 1L Basic Troubleshooting Intermittents An intermittent fault is the most difficult to troubleshoot since the MIL flashes on at random causing uncertainty in the number of flashes or the conditions present at the time of the fault Also the problem may or may not fully turn ON the MIL light or store a code Therefore the fault must be present or able to be recreated in order to locate the problem If a fault is intermittent use of diagnostic code charts may
55. ing the Service Tool Display Buck s Engines 40 Manual 36548 PG 08 Engine Control System for GM 8 1L Chapter 6 Basic Troubleshooting Preliminary Checks PG 08 systems are equipped with built in fault diagnostics Detected system faults can be displayed by the Malfunction Indicator Lamp MIL and are covered in Chapter 7 Advanced Diagnostics However items such as fuel level plugged fuel lines clogged fuel filters and malfunctioning pressure regulators may not set a fault code and usually can be corrected with the basic troubleshooting steps described on the following pages If engine problems are encountered with your PG 08 system perform the checks in this section before referring to Advanced Diagnostics NOTE Locating a problem in a natural gas engine is done exactly the same as with a gasoline engine Consider all parts of the ignition and mechanical systems as well as the fuel system BEFORE STARTING 1 Determine that the SECM and MIL light are operating Verify operation by keying on engine and checking for flash of MIL light When the ignition key is turned on the MIL will illuminate and remain on until the engine is started Once the engine is started the MIL lamp will go out unless one or more fault conditions are present If a detected fault condition exists the fault or faults will be stored in the memory of the small engine control module SECM Once an active fault occurs the MIL will illuminate and rema
56. ins A16 B17 Oz Pin 1 power to SECM DRVP 12V Pin A23 Verify O2 sensor heater circuit is operating by measuring heater resistance 2 10 0 4Q Oz Pin C GND to Pin D power 76 Manual 36548 GasPostO2NotActive Post catalyst O2 sensor inactive on natural gas open Oz sensor signal or heater leads defective O2 sensor GasO2FailedLean Pre catalyst O2 sensor indicates extended lean operation on natural gas GasPostO2FailedLean Post catalyst O2 sensor indicates extended lean operation on natural gas GasO2FailedRich Pre catalyst O2 sensor indicates extended rich operation on natural gas PG 08 Engine Control System for GM 8 1L Table 2 Diagnostic Fault Codes Flash Codes cont d FAULT DFC PROBABLE FAULT ACTION 1 TurnOnMIL 2 DisableGasPost O2Ctrl 1 TurnOnMIL 2 DisableGas O2Ctrl 1 TurnOnMIL 2 DisableGasPost O2Ctrl 1 TurnOnMIL 2 DisableGas O2Ctrl CORRECTIVE ACTION FIRST CHECK Check that Post catalyst O2 sensor connections are OK Oz signal Pin B to SECM Pin B19 Os Pin C GND to SECM DRVG GND Pins A16 B17 Os Pin D power to Post O2 Heater Relay Relay pin 87 This relay only turns on after engine has been running for some time and SECM has calculated that water condensation in exhaust has been removed by exhaust heat Post O2 Heater Relay has SECM DRVP 12V applied to the relay coil power The relay coil ground is controlled by SECM Pin A20 to activ
57. l inlet port The regulating valve is at a fixed position that is determined by the setting of the screw on top of the regulator when no gas is flowing When the fuel lock off is opened fuel will flow into the inlet and straight through the regulator If there is no fuel demand the outlet pressure will increase causing a force imbalance on the valve diaphragm that will close the valve When the engine is running the valve will open to maintain the outlet pressure at the setting commanded by the system The valve will open wider for higher fuel flow demands and will close for lower fuel flow demands Buck s Engines 14 Manual 36548 PG 08 Engine Control System for GM 8 1L D100 Mixer The mixer is installed above the throttle body and meters gaseous fuel into the airstream at a rate that is proportional to the volumetric flow rate of air The ratio between volumetric airflow and volumetric fuel flow is controlled by the size of the metering orifices inside the venturi and biased by the restriction in the fuel supply line provided by the L Series trim valve Fuel flow must be metered accurately over the full range of airflows Pressure drop across the mixer air valve must be minimized to assure maximum power output from the engine Figure 4 D100 Mixer D100 Venturi Mixer Operation Vapor natural gas fuel is supplied to the D100 mixer by the Maxitrol 210DZ pressure regulator When air enters the mixer the pressure will drop at the throat
58. le ETC_Sticking Electronic Throttle Control is sticking This can occur if the throttle plate butterfly valve inside the throttle bore is sticking The plate sticking can be due to some type of obstruction a loose throttle plate or worn components shaft bearings NOTE The throtile assembly is not a serviceable item and can only be repaired by replacing the DV EV throttle assembly ETC_Open_Fault Electronic Throttle Control Driver has failed normally set if either of the ETC driver signals have opened or become disconnected electronic throttle or SECM is defective HbridgeFault_ETC Electronic Throttle Control Driver has failed Indeterminate fault on Hbridge driver for electronic throttle control Possibly either ETC or ETC driver signals have been shorted to ground Buck s Engines TurnOnMIL 1 TurnOnMIL 2 EngineShut down 3 CutThrottle TurnOnMIL TurnOnMIL Check ignition module wiring and connector for shorts SECM Pin A9 EST1 to ignition module Pin B Verify GND on ignition module Pin C Verify 12 Vdc on ignition module PinA Refer to application manual for specific engine details Check for debris or obstructions inside the throttle body e Check throttle plate shaft for bearing wear Check the ETC driver wiring for an open circuit SECM Pin A17 to ETC Pin 1 SECM Pin A18 to ETC Pin 4 Check the ETC internal motor drive by disconnecting the throttle connecto
59. levels the SECM uses a heated exhaust gas oxygen sensor HEGO mounted before the catalyst to measure exhaust gas content in the fuel system Engine speed is monitored by the SECM through a Hall Effect type sensor Intake manifold air temperature and absolute pressure are monitored with a TMAP sensor The HEGO voltage is converted to an air fuel ratio value This value is then compared to a target value in the SECM The target value is based on optimizing catalyst efficiency for a given load and Buck s Engines 22 Manual 36548 PG 08 Engine Control System for GM 8 1L speed The SECM then calculates any corrections that need to be made to the air fuel ratio The system operates in open loop fuel control until the engine has done a certain amount of work This ensures that the engine and HEGO are sufficiently warmed up to stay in control In open loop control the FTV duty cycle is based on engine speed and load Once the HEGO reaches operating temperature the fuel management is in closed loop control for all steady state conditions from idle through full throttle In closed loop mode the FTV duty cycle is based on feedback from the HEGO sensor The system may return to open loop operation when engine load or engine speed vary beyond a chosen threshold The SECM makes any necessary corrections to the air fuel ratio by controlling the inlet fuel pressure to the air fuel mixer Reducing the fuel pressure leans the air fuel mixture and increa
60. m an additional relay that is controlled by the SECM This relay is only energized when the SECM calculates that water condensation in the exhaust system and catalytic converter prior to the sensor should be evaporated This is to avoid thermal shock of the sensor that could prematurely fail the sensor The HEGO stoichiometric air fuel ratio voltage target is approximately 500 mV and changes slightly as a function of speed and load When the pre catalyst HEGO sensor sends a voltage signal less than 450 mV the SECM interprets the air fuel mixture as lean The SECM then decreases the PWM duty cycle sent to the fuel trim valves in order to increase the fuel pressure to the mixer inlet thus richening air fuel mixture The opposite is true if the SECM receives a voltage signal above 450 mV from the HEGO The air fuel mixture would then be interpreted as being too rich and the SECM would increase the duty cycle of the trim valves CAUTION The HEGO sensors are calibrated to work with the PG 08 control system Use of alternate sensors may impact performance and the ability of the system to diagnose rich and lean conditions Catalytic Converter In order to meet 2008 emission requirements a 3 way catalyst is necessary The PG 08 control system monitors the exhaust stream pre and post catalyst and uses this information to control the air fuel mixture By using the signals from the HEGOs the SECM can increase or decrease the amount of oxygen in the
61. moval and reinstallation of the 210DZ regulator NOTE Regulator tower must be in vertical position for proper installation Figure 15 210DZ Regulator Buck s Engines 35 Manual 36548 PG 08 Engine Control System for GM 8 1L Removal and Installation of D100 Mixer CAUTION The regulator and mixer are part of a certified system complying with EPA and CARB 2008 requirements Only trained certified technicians should perform disassembly service or replacement of the regulator or mixer Follow the procedures below for removal and reinstallation of the D100 mixer D100 Mixer Removal Steps Refer to Figure 16 1 2 N DOT OO 9 Close fuel supply line to the engine Purge the system of fuel by starting the engine and running until all trapped fuel in the system is exhausted and the engine shuts down Key switch in OFF position Remove the air cleaner Remove the vacuum line Remove fuel line 2 from the trim valve inlet Disconnect the wires leading to the electronic throttle body by pinching the lock tabs on either side of the wiring harness connector See Figure 17 for location of connector Loosen the lower hose clamp on the hose 3 between the mixer 4 and the throttle body 5 Gently wiggle and pull to separate mixer adapter hose assembly from the throttle body 10 Remove the trim valve 8 from the mixer body Figure 16 D100 Mixer Installed on Engine
62. n e Min max governing e All speed isochronous governing e Fixed speed isochronous governing with three switch selectable speeds e Fuel enrichment and spark timing modifiers for temperature and fuel type e Transient fuel enrichment based on rate of change of TPS e Input sensor selection and calibration Buck s Engines 10 Manual 36548 PG 08 Engine Control System for GM 8 1L e Auxiliary device control for fuel pump fuel lock off solenoid MIL interlocks engine speed limiting etc e CANBus data transfer for speed torque etc Other System Features Include Tamper Resistance Applications Using Commercial Grade Fuel Special tools equipment knowledge and authorization are required to effect any changes to the PG 08 system thereby preventing unauthorized personnel from making adjustments that will affect performance or emissions Diagnostics PG 08 is capable of monitoring and diagnosing problems and faults within the system These include all sensor input hardware control output hardware and control functions such as closed loop fuel control limits and adaptive learn limits Upon detecting a fault condition the system notifies the operator by illuminating the MIL and activating the appropriate fault action The action required by each fault shall be programmable by the OEM at the time the engine is calibrated Diagnostic information can be communicated through both the Service Tool interface and the MIL lamp Wit
63. n off fuel trim valve with a minimum impedance of 5 ohms Capable of continuous on time Drive circuit designed for minimum turn on turn off delay FTV command will be given as a PWM signal at 400 hz witha duty cycle between 10 and 90 Fuel lock off solenoid valve Low side switch 10A peak 4A continuous 45 V max Electronic Spark Timing EST 8 TTL compatible outputs Software configured for coil on plug ignition system Throttle control 1 H Bridge 5A peak 2 5A continuous at 2500 Hz PWM includes current feedback for diagnostic purposes MIL malfunction indicator lamp Low side switch sufficient to drive a 7W incandescent lamp continuously Autostart autocrank relay drive Low side switch sufficient to drive a relay to control starter operation CANBus CAN 2 0b serial communication for J1939 communications programming and diagnostics Requires proper termination resistance per CAN 2 0b Buck s Engines 25 Manual 36548 PG 08 Engine Control System for GM 8 1L Chapter 2 Specifications EE Fuel System Requirements Operating Temperature 20 F to 221 F 29 C to 105 C Long term Storage Temperature 40 F to 140 F 40 C to 60 C Short term Storage Temperature lt 257 F 125 C Heat Soak Natural Gas Composition Minimum 55 methane content Requirements Energy content from 900 to 1550 BTU ft 3 Environmental Electrical Specifications Ambient Operating Temperature 20 F to
64. ncas EE OR EE EER EN 13 Maxitrol 210DZ Pressure Regulator sees see ee Re Re ee 14 D100 NC EE OE N AEA RAA EE 15 Electronic Throttle System iese ee ese ee RA Re ee eke ek ee RA ee Re ee ee ee 16 PG 08 Electronic Throttle esse eek RA Re ee RA eke ee ee 16 Ignition SYSTEM RR EE ER EE EN 18 General Motors GM Coil Near Plug Ignition System iese see ee eke 18 Exhaust SySte RE EE EE ER NE RE HE ER 20 ouder ORE EE RE EE EEN 20 EG ER ER EDE ER EE ER EG 22 Fuel Management i s ss EE EE N Ee De gee Es tens N eN eet EE be Ee eg be ie 22 Speed Management RA Re AR AA RR Re Re ke Re ee 23 SECM KA EE EE EO OE 24 leed nee AA ER feexvacrenees auexeereds 24 Frequency Position INDutS nerens ee ee ee Re ee AE Re ee AE Ee AR ee ee ee ee 24 Digital IMPUS N OE OE EE EE EE EN 25 ed NE NE N EE N EE 25 CHAPTER 2 SPECIFICATIONS esse kosse sind es ane sesse de sea ve lee EE N kk N ee 26 Fuel System Requirement ies ss de Re AR AA AA RA Re Re ee ee 26 Environmental Electrical SpecificationS sesse esse ee ees eke ee Re ee ede ee Re ee 26 210DZ Pressure Regulator Specificati0OnS sees ke Re Re ke Re ee 26 D100 Mixer Specifications ee RA Re RA ke RA Re Re ek ee ee ee 27 Electronic Throttle System Specifications eise ese ee Re Re Re RA Re ee 27 SECM Specifications aisneis ee ee ee ee AG RA ee Re Re AA Ge Ge ee ee de 27 Fuel Trim Valve FTV Specifications see ke RA RA Re RA Re Re ee 28 Ignition System Speci
65. nputs The 48 pin SECM is equipped with sufficient analog inputs for the following sensors e Manifold Absolute Pressure MAP 1bar MAP 0 to 5 V e Manifold Air Temperature MAT 40 F to 266 F 40 C to 130 C range 48 kohm to 85 ohm sensor range e Throttle Position Sensor 1 amp 2 TPS1 amp TPS2 0to5V e Foot Pedal Position 1 amp 2 FPP1 amp FPP2 0 to 5 V e Coolant Temperature Sensor CTS 40 F to 266 F 40 C to 130 C range 48K ohm to 85 ohm sensor range e HEGO 3 0to1V e Oil Pressure 1 0to5V e Auxiliary Analog Input 1 0 to 5 V e Battery Voltage Vbatt 1 8 18 V With the exception of battery voltage all inputs are 0 5 Vdc ground referenced Resolution should be 0 1 or better Accuracy should be 2 or better Frequency Position Inputs e Crankshaft position Buck s Engines 24 Manual 36548 PG 08 Engine Control System for GM 8 1L Variable reluctance 2 wire 200 Vpp max or 0 5 V Hall Effect with calibration selectable pull up resistor for open collector sensors Permits speed resolution of 0 25 rom and crankshaft position resolution of 0 5 Camshaft position Variable reluctance 2 wire 200 Vpp max or 0 5 V Hall Effect with calibration selectable pull up resistor for open collector sensors Digital Inputs Outputs Speed select switch Permits selecting four different maximum engine speeds Vswitched Switched battery voltage FTV drivers 2 1 used 10A peak 45V max To drive an o
66. ns Is acceleration too much too often Check air cleaner element filter for being dirty or plugged Visually physically check vacuum hoses for splits kinks and proper connections PROBABLE CAUSE CORRECTIVE ACTION Check for faulty pressure regulator Check that trim valve duty cycle is lt 15 Check for too high natural gas pressure at mixer gt 1 positive pressure Monitor Pre catalyst O2 sensor with Service Tool Fuel system malfunction Check engine coolant level Check engine thermostat for faulty part always open or for wrong heat range Cooling system malfunction Check ignition timing Check for weak ignition and or spark control Ignition system Check spark plugs Remove spark plugs and check malfunction for wet plugs cracks wear improper gap burned electrodes or heavy deposits Repair or replace as necessary Check for exhaust system restriction or leaks Check induction system and crankcase for air leaks Check for clogged air filter clean or replace as required Component malfunction Check FTV for housing cracks or obstructions repair or replace as required Check for vacuum leak Check system vacuum hoses from regulator to FTV and mixer Repair or replace as required Pressure regulator Test regulator operation and pressure malfunction fuel pressure too high See Chapter 5 Tests and Adjustments l Check compression Engine mechanical Refer to Engine Manufacturer s Ser
67. ntaminated the SECM will not deliver correct amount of fuel resulting in a performance problem Ignition system Check ignition system wires plugs etc malfunction Natural gas pressure Test regulator operation and pressure regulator malfunction See Chapter 5 Tests and Adjustments Check throttle for sticking or binding Check PCV valve for proper operation by placing finger over inlet hole in valve end several times Valve should snap back If not replace valve Check alternator output voltage Repair if less than 9 or more than 16 volts Ename mechanical Perform a cylinder compression check 9 See Engine Manufacturer s Service Manual continued on next page Component malfunction Buck s Engines 50 Manual 36548 PG 08 Engine Control System for GM 8 1L Basic Troubleshooting cont d Rough Unstable Incorrect Idle or Stalling cont d PROBABLE CAUSE CORRECTIVE ACTION Repair replace as required f Clogged iual miaf See Chapter 3 Fuel Filter Replacement Remove obstruction from the fuel line e Using caution disconnect the fuel line Plugged fuel line some natural gas may escape e Clear obstruction with compressed air e Re connect fuel line 4 Repair replace fuel lock off Fuel lock off malf See Chapter 3 Fuel Lock Off Check connection Faulty vapor connection e Verify no holes in hose between the pressure e Clamps must be tight regulator and the mixer e Look for kinked pinched and or
68. on burned electrodes or heavy deposits Repair or replace as necessary Check condition of distributor cap rotor and spark plug wires where applicable Check ignition timing Check vacuum lines for kinks or leaks Component malfunction Check alternator output voltage Repair if less than 9 or more than 16 volts Check condition of exhaust system Exhaust backpressure Check backpressure before catalyst It should be less than 3 5 psig 24 13 kPa Refer to Table 1 for description of gaseous O2 adapts Related MIL Faults Pre catalyst O2 sensor errors O2 control errors Trim valve DC faults EST faults ETC faults L Series fault Buck s Engines 43 Manual 36548 PG 08 Engine Control System for GM 8 1L Basic Troubleshooting cont d Engine Cranking but Will Not Start Difficult to Start Engine cranks OK but does not start for a long time Does eventually run or may start but immediately dies PRELIMINARY CHECKS Perform the visual checks as described at start of Basic Troubleshooting chapter Be sure operator is using correct method to start engine as explained in operator s manual Use clear flood mode during cranking by fully depressing the pedal and cranking the engine If engine does not start continue troubleshooting PROBABLE CAUSE CORRECTIVE ACTION Remove obstruction from the fuel line e Using caution disconnect the fuel line some natural gas may escape e Clear o
69. oo _Z Buck s Engines Service Manual PG 08 Integrated Engine Control System for GM 8 1L Engines 2008 Emission Certified Non Adjustable Natural Gas Fuel System Revision 01 y UE Powertrain Buck s Engines Limited Mechanical Warranty on New GM Powertrain Engines Manufactured by Buck s Engines Used In Industrial Applications Terms of Coverage Uses This warranty applies to the first retail purchaser and subsequent owners during the WARRANTY PERIOD for new GM Powertrain Engines manufactured by Buck s Engines referred to as Engine that are used in industrial applications Defects This warranty covers Engine REPAIRS to correct any warranted malfunction occurring during the WARRANTY PERIOD resulting from defects in material or workmanship Repairs To obtain warranty repairs you must request the needed repairs within the WARRANTY PERIOD from an authorized Buck s Engines service outlet Repairs covered by this warranty must be pre approved by a Buck s Engines authorized representative Only new genuine parts or remanufactured parts or components supplied or approved by Buck s Engines will be used Buck s Engines may at its discretion replace rather than repair components A reasonable time must be allowed to perform the warranty repair after taking the Engine to the authorized service outlet Repairs will be performed during normal business hours This Warranty Does Not Cover Repairs Due to Accidents Misus
70. oolant temperature faults Buck s Engines 48 Manual 36548 PG 08 Engine Control System for GM 8 1L Basic Troubleshooting cont d Backfire Fuel ignites in intake manifold or in exhaust system making loud popping noise PRELIMINARY CHECKS Perform the visual checks as described at start of Basic Troubleshooting chapter Simulate condition by reviewing operation procedure practiced by engine operator PROBABLE CAUSE CORRECTIVE ACTION Perform fuel system diagnosis check Fuel system e Check for fuel leaks malfunction e Check for MIL faults e Check for damaged components Check proper ignition coil output voltage with spark tester Check spark plugs Remove spark plugs check for wet Ignition system plugs cracks wear improper gap burned electrodes malfunction or heavy deposits Repair or replace as necessary Check spark plug wires for crossfire and proper routing Check ignition timing Check compression look for sticking or leaking valves Engine mechanical Check intake and exhaust manifold for casting flash and gasket misalignment Related MIL Faults EST faults ETC faults Encoder error Pre catalyst O2 sensor faults Dieseling Run on Engine continues to run after key is turned OFF but runs very roughly If engine runs smoothly check ignition switch and adjustment PRELIMINARY CHECKS Perform the visual checks as described at start of Basic Troubleshooting chapter
71. or Intake manifold air temperature and absolute pressure are monitored with a TMAP sensor PG 08 is a drive by wire DBW system connecting the accelerator pedal to the electronic throttle through the electrical harness mechanical cables are not used A throttle position sensor TPS monitors throttle position in relation to the accelerator pedal position sensor APP command Even engine coolant temperature and adequate oil pressure are monitored by the SECM The SECM controller has full adaptive learning capabilities allowing it to adapt control function as operating conditions change Factors such as ambient temperature fuel variations ignition component wear clogged air filter and other operating variables are compensated PG 08 Closed Loop Natural Gas Fuel System CAMSHAFT SENSOR PRE CATALYST OXYGEN SMALL SENSOR ENGINE CONTROL POST CATALYST MODULE OXYGEN SENSOR COOLANT SENSOR TRANS MISSION OIL TEM OIL IGNITION PRESSURE COILS SWITCH ELECTRONICL enoine L CATALYTIC THROTTLE more MUFFLER Figure 2 PG 08 Closed Loop NG Fuel System Buck s Engines Manual 36548 PG 08 Engine Control System for GM 8 1L PG 08 System Components The PG 08 control system provides electronic control to the following subsystems on stationary industrial engines e Fuel delivery system e Spark ignition control system e Air throttle e Sensors Switches Speed inp
72. or has opened TPS2RangeHigh TPS sensor voltage out of range high 1 TurnOn normally set if the MIL TPS signal has 2 Cut shorted to power or Throttle the ground for the sensor has opened TPS1AdaptLoMin Learned closed throttle value of TPS sensor range lower than expected TPS2AdaptLoMin Learned closed throttle value of TPS2 sensor range lower than expected TPS1 AdaptHiMax Learned WOT value of TPS sensor range higher than expected TPS2AdaptHiMax Learned WOT value of TPS sensor range higher than expected TPS1AdaptHiMin Learned WOT value of TPS sensor range lower than expected TPS2AdaptHiMin Learned WOT value of TPS sensor range lower than expected FAULT CORRECTIVE ACTION PROBABLE FAULT ACTION FIRST CHECK Check throttle connector and TPS sensor wiring for a shorted circuit SECM Pin B23 signal to ETC Pin 6 SECM Pin B1 sensor GND to ETC Pin 2 Check throttle connector and TPS sensor wiring for a shorted circuit SECM Pin B4 signal to ETC Pin 5 SECM pin B1 sensor GND to ETC Pin 2 Check the throttle connector and pins for corrosion To check the TPS disconnect the throttle connector and measure the resistance from TPS Pin 2 GND to Pin 6 TPS SIGNAL 0 7 Q 30 TPS Pin 3 PWR to Pin 6 TPS SIGNAL 1 4 Q 30 Check the throttle connector and pins for corrosion To check the TPS disconnect the throttle connector and measure the resistance from TPS Pin 2 GND to Pin 5
73. pair or replace throttle When indicated by MIL assembly y meae O _ x _ Replace airttersiemens _ x _ Check TMAP sensor for tightness and leaks Exhaust amp Emission Inspect engine for exhaust leaks Replace PCV valve and X breather element Replace HEGO sensors d x Buck s Engines 33 Manual 36548 PG 08 Engine Control System for GM 8 1L Chapter 4 Installation Procedures WARNING PROPER USE e Natural gas is highly flammable To prevent personal injury keep fire and flammable materials away from the lift truck when work is done on the fuel system Gas vapor may reduce oxygen available for breathing cause headache nausea dizziness and unconsciousness and lead to injury or death Always operate equipment in a well ventilated area CAUTION The regulator and mixer are part of a certified system complying with EPA and CARB 2008 requirements Only trained certified technicians should perform disassembly service or replacement of the regulator or mixer Buck s Engines 34 Manual 36548 PG 08 Engine Control System for GM 8 1L Removal and Installation of 210DZ Regulator CAUTION The regulator and mixer are part of a certified system complying with EPA and CARB 2008 requirements Only trained certified technicians should perform disassembly service or replacement of the regulator or mixer Refer to the installation instructions provided by the engine packager for re
74. power is supplied to the fuel lock off via the main power relay with the SECM controlling the lock off ground earth connection The lock off remains in a normally closed NC position until the key switch is activated This supplies power to the lock off and the SECM but will not open the lock off via the main power relay until the SECM provides the lock off ground connection This design gives the SECM full control of the lock off while providing additional safety by closing the fuel lock off in the unlikely event of a power failure wiring failure or module failure Buck s Engines 12 Manual 36548 PG 08 Engine Control System for GM 8 1L When the fuel supply service valve is opened natural gas flows through the service line to the fuel lock off Natural gas enters the lock off through the inlet port and stops with the lock off in the normally closed position When the engine is cranked over the main power relay applies power to the lock off and the SECM provides the lock off ground causing current to flow through the windings of the solenoid creating a magnetic field The strength of this magnetic field is sufficient to lift the lock off valve off of its seat against spring pressure When the valve is open natural gas at line pressure flows through the lock off outlet to the pressure regulator A stall safety shutoff feature is built into the SECM to close the lock off in case of a stall condition The SECM monitors three engine states C
75. r and measuring the motor drive resistance at the throttle ETC Pin 1 DRIVER to Pin 4 DRIVER 3 0 4 0 Check the ETC driver wiring for an open circuit SECM Pin A17 to ETC Pin 1 SECM Pin A18 to ETC Pin 4 Check the ETC internal motor drive by disconnecting the throttle connector and measuring the motor drive resistance at the throttle ETC Pin 1 DRIVER to Pin 4 DRIVER 3 0 4 0 Check ETC driver wiring for a shorted circuit SECM Pin A17 to ETC Pin 1 SECM Pin A18 to ETC Pin 4 Check the ETC internal motor drive by disconnecting the throttle connector and measuring the motor drive resistance at the throttle ETC Pin 1 DRIVER to Pin 4 DRIVER 3 0 4 0 73 Manual 36548 PG 08 Engine Control System for GM 8 1L Table 2 Diagnostic Fault Codes Flash Codes cont d FAULT CORRECTIVE ACTION PROBABLE FAULT ACTION FIRST CHECK Check engine oil level Check electrical connection to DelayedEngine the oil pressure switch Shutdown SECM Pin B9 to Oil Pressure Switch Check battery voltage e Perform maintenance check on electrical connections to the battery and chassis ground Check battery voltage during starting and when the engine is running to SysVoltRangeLow System voltage too low Pare verify charging system and alternator function Measure battery power at SECM with a multimeter with key on SECM Pin A23 DRVP to SECM Pin A16 DRVG SECM Pin A23 DRVP to SECM Pin B17 DRVG LowOilPre
76. rank when the crankshaft position sensor detects any engine revolutions Stall when the key is in the ON position but the crankshaft position sensor detects no engine revolutions and the Run state when the engine reaches pre idle rpm When an operator turns on the key switch the lock off is opened but if the operator fails to crank the engine the SECM will close the lock off after approximately 5 seconds Fuel Filter A fuel filter should be placed in the fuel line upstream from the fuel lock off The fuel filter protects fuel system components from particulates and other contaminates that may be present in the fuel NOTE Gi For system durability a fuel filter should be installed upstream of the lock off The filter should be 10 micron or better at 99 efficiency Failure to use a filter may result in reduced system performance and durability Buck s Engines 13 Manual 36548 PG 08 Engine Control System for GM 8 1L Maxitrol 210DZ Pressure Regulator The pressure regulator receives gaseous natural gas from the supply line 8 15 inH20 37 3 76 7 mbar It drops the pressure and provides vapor phase natural gas at a regulated outlet pressure to the trim valve The outlet pressure of the regulator will be approximately equal to the pressure of the air entering the venturi mixer Figure 3 Maxitrol 210DZ Regulator Regulator Operation Natural gas at line pressure enters the 210DZ through the fue
77. re will be a long pause then one flash 1 pause then two flashes 2 This identifies a twelve signifying the end of the fault list This list will then repeat Displaying and Clearing Fault Codes DFC from SECM Memory Retrieving and clearing fault codes without the use of the PG 08 service tool is possible by using a device to cycle the speed input through the SECM s potentiometer connection Accomplishing code retrieval and clearing requires a special device This device has the capability of cycling the potentiometer input at a specific frequency through a specific voltage range that will initiate both code flashing on MIL and code clearing Contact Buck s Engines for information and availability of such a device CAUTION Once the fault list is cleared it cannot be restored Buck s Engines 58 Manual 36548 PG 08 Engine Control System for GM 8 1L Fault Action Descriptions Each fault detected by the SECM is stored in memory FIFO and has a specific action or result that takes place Listed below are the descriptions of each fault action Engine Shutdown The most severe action is an Engine Shutdown The MIL will light and the engine will immediately shut down stopping spark and closing the fuel lock off solenoid valve Delayed Engine Shutdown Some faults such as low oil pressure will cause the MIL to illuminate for 30 seconds and then shut down the engine Cut Fuel Fuel flow will be turned off Cut Throttle
78. re as follows When operating on natural gas 8000 hour deteriorated emissions shall be less than or equal to NMHC 1 0 g hp hr CO 4 0 g hp hr NOx 2 0 g hp hr The PG 08 control system complies with New Source Performance Standards NSPS and National Emission Standards for Hazardous Air Pollutants NESHAP proposed by the EPA These standards are effective in 2008 for stationary spark ignited engines As defined in applicable regulations the engine control system is designed to maintain emissions compliance for ten 10 years or 8000 hours whichever occurs first provided appropriate maintenance is performed as defined in the service manual for the system Maintenance intervals shall be defined and approved by the regulating body Component warranty shall comply with regulatory requirements 40 CFR Part 1048 120 for all emission related components Warranty for non critical emissions components will be as defined in the individual purchase agreement North American Compliance The 210DZ regulator is UL listed per Category MIMV2 The 210DZ regulator has tamper resistant features approved by the California Air Resources Board CARB when used with commercial grade fuel Buck s Engines Manual 36548 PG 08 Engine Control System for GM 8 1L Electrostatic Discharge Awareness All electronic equipment is static sensitive some components more than others To protect these components from static damage you must take special pr
79. retail purchaser or put into service whichever occurs first In any event the WARRANTY PERIOD will commence no later than one year after the Engine s model year production ends The WARRANTY PERIOD will end at the time limits shown below Warranty Limitations Whichever Occurs First ITEM MONTHS ENGINE HOURS Engine and Internal Moving Parts 3 500 Hours Electrical Components 1 000 Hours Cooling System Components Po 2 000 Hours No Other Warranty THIS LIMITED WARRANTY IS THE ONLY WARRANTY APPLICABLE TO THESE ENGINES BUCK S ENGINES MAKES NO OTHER WARRANTIES EXPRESS OR IMPLIED September 2010 UE Powertrain LP d b a Buck s Engines 20 N McCormick Oklahoma City Oklahoma 73127 WARNING DANGER OF DEATH OR PERSONAL INJURY WARNING FOLLOW INSTRUCTIONS Read this entire manual and all other publications pertaining to the work to be performed before installing operating or servicing this equipment Practice all plant and safety instructions and precautions Failure to follow instructions can cause personal injury and or property damage WARNING OVERSPEED PROTECTION The engine turbine or other type of prime mover should be equipped with an overspeed shutdown device to protect against runaway or damage to the prime mover with possible personal injury loss of life or property damage The overspeed shutdown device must be totally independent of the prime mover control system An overtemperature or overpressure shutdown d
80. rl 1 TurnOnMIL 2 DisableGasPost O2Ctrl 1 TurnOnMIL 2 DisableGas O2Ctrl 1 TurnOnMIL 2 DisableGasPost O2Ctrl CORRECTIVE ACTION FIRST CHECK Correct other faults that may contribute to 772 e g faults pertaining to FTV Pre Cat Oz Post Cat O2 sensor Look for leaks in exhaust catalytic converter HEGO sensors repair leaks Check all sensor connections see fault 742 corrective actions Check if O2 sensor installed before the catalyst is shorted to GND or sensor GND Oz signal Pin B to SECM Pin B13 SECM DRVG GND Pins A16 B17 SECM sensor GND Pin B1 Check if Oz installed after the catalyst sensor is shorted to GND or sensor GND Os signal Pin B to SECM Pin B19 Possible sources SECM DRVG GND Pins A16 B17 and SECM sensor GND Pin B1 Check if O2 sensor installed before catalyst is shorted to 5Vdc or battery Oz signal Pin B to SECM Pin B13 SECM PWR Pin B24 SECM power Pin A23 Check if O2 sensor installed after catalyst is shorted to 45Vdc or battery Oz signal Pin B to SECM Pin B19 Possible voltage sources SECM PWR Pin B24 and SECM power Pin A23 78 Manual 36548 PG 08 Engine Control System for GM 8 1L Table 2 Diagnostic Fault Codes Flash Codes cont d FAULT CORRECTIVE ACTION DES PRDEAELEEAUET ACTION FIRST CHECK ServiceFault4 Replace Pre catalyst HEGO Service Interval 4 has sensor been reached replace ee Replace Post cataly
81. rottle bore is sticking The plate sticking can be due to some type of obstruction a loose throttle plate or worn components shaft bearings NOTE Throttle assembly is not a serviceable item and can only be repaired by replacing the DV EV throttle assembly 461 FuelSelectConflict Conflict in fuel select signals normally set if one or both of the fuel select signals are shorted to ground 181 FuelT empRangeHigh Fuel Temperature Sensor Input is High Normally set if the fuel temperature sensor wire has been disconnected or the circuit has opened to the SECM 932 FuelTempRangeLow Fuel Temperature Sensor Input is Low Normally set if the fuel temperature sensor wire has shorted to chassis ground or the sensor has failed 931 GasFuelAdaptRangeHi In natural gas mode system had to adapt lean more than expected 731 GasFuelAdaptRangelo In natural gas mode system had to adapt rich more than expected 721 GasO 2FailedLean Pre catalyst O sensor indicates extended lean operation on natural gas 751 Buck s Engines 62 Manual 36548 PG 08 Engine Control System for GM 8 1L Table 1 Fault List Definitions cont d FAULT DESCRIPTION CODE GasO2FailedRich Pre catalyst Os sensor indicates extended rich operation on natural gas 771 GasO2NotActive Pre catalyst O sensor inactive on natural gas open O sensor signal or heater leads defe
82. rovides this control The system consists of the following components e SECM e Ignition coils e Crankshaft position sensor e Crankshaft timing wheel e Camshaft position sensor e Camshaft timing wheel e Spark plugs The SECM through use of embedded control algorithms and calibration variables determines the proper time to start energizing the coil and fire the spark plug This requires accurate crank camshaft position information an engine speed calculation coil energy information and target spark timing The SECM controls spark energy dwell time and spark discharge timing General Motors GM Coil Near Plug Ignition System The GM 8 1L engine has a coil near plug ignition system The engine comes equipped with eight coils one per cylinder that are mounted near each cylinder A high tension ignition wire connects the output of each coil to the spark plug in each cylinder The coils provided with the GM 8 1L engine provide a control interface that allows external control modules to control engine timing and dwell When the SECM sends a 5 volt signal to the control interface the coil control module begins charging the coil When the SECM signal returns to the ground state the coil discharges into the spark plug In this way the amount of time the SECM signal is in the high state determines the coil dwell The moment that the signal returns to the ground state determines when the spark plug fires The SECM uses the crankshaft
83. s High Normally set if coolant sensor wire has been disconnected or circuit has opened to the SECM 151 Buck s Engines 61 Manual 36548 PG 08 Engine Control System for GM 8 1L Table 1 Fault List Definitions cont d FAULT DESCRIPTION CODE ECTRangeLow Engine Coolant Temperature Sensor Input is Low Normally set if the coolant sensor wire has shorted to chassis ground or the sensor has failed 141 ECT_IR_Fault Engine Coolant Temperature not changing as expected 171 EST1_Open EST1 output open possibly open EST1 signal or defective spark module 421 EST1 Short EST1 output shorted high or low EST1 signal shorted to ground or power or defective spark module 431 ETCSpringTest Electronic Throttle Control Spring Return Test has Failed The SECM will perform a safety test of the throttle return spring following engine shutdown If this spring has become weak the throttle will fail the test and set the fault NOTE Throttle assembly is not a serviceable item and can only be repaired by replacing the DV EV throttle assembly 481 ETC_Open_Fault Electronic Throttle Control Driver has failed Normally set if either of the ETC driver signals have opened or become disconnected electronic throttle or SECM is defective 471 ETC_Sticking Electronic Throttle Control is Sticking This can occur if the throttle plate butterfly valve inside the th
84. sch Electronic Throttle Body ie ee ee ee ee ee ee be ee 16 Figure 9 Throttle Body Assembly Exploded VieW sees ese ees ee ee de eke ee ee ee ee 17 Figure 10 HEGO 02 SeNSOF e ees ee esse ee ese ee ee ee ee ee ee eed ee ee ee ee ee eke ee Re ee ee 20 Figure 11 Throttle Position Sensor TPS on DV E5 Throfle sesse sesse see 23 Figure 15 210DZ RegulatOF iss sg Es SEEN ESE NNA A 35 Figure 16 D100 Mixer Installed on Engine sees esse ee ee ee ee Re ee ee ee ee ee 36 Figure 17 Wire Harness Connector on Throttle Body 37 Figure 19 Regulator Pressure Test Connections ees ke ke 38 Figure 21 KVaser Communication Adapter sesse ee Re Re Re RA ee 40 Figure 22 Crypt Token Installed on Laptop iese sees ke Re Re ke RA ke 40 Figure 23 Opening the Service Tool Display iese Re RA RA ke 40 Figure 26 Installing Exhaust Backpressure Tester sesse ee dee ee ee ee ee 57 Buck s Engines Manual 36548 PG 08 Engine Control System for GM 8 1L Regulatory Compliance EPA CARB Emissions Certification When properly applied and calibrated Buck s Engines PG 08 control system meets EPA 2008 stationary emission standards for rich burn natural gas 40 CFR Part 60 when operating properly with an approved three way catalyst The emissions test is based on the ISO 8178 type D2 steady state test cycle The emission standards including appropriate deterioration factors over the useful life of the system a
85. sed throttle value of TPS sensor range higher than expected 281 TPS1AdaptLoMin Learned closed throttle value of TPS sensor range lower than expected 241 TPS1RangeHigh TPS sensor voltage out of range high normally set if the TPS signal has shorted to power or ground for the sensor has opened 231 TPS1RangeLow TPS sensor voltage out of range low normally set if TPS signal has shorted to ground circuit has openedor sensorhas failed 221 TPS2AdaptHiMax Learned WOT value of TPS sensor range higher than expected 252 TPS2AdaptHiMin Learned WOT value of TPS sensor range lower than expected 272 TPS2AdaptLoMax Learned closed throttle value of TPS sensor range higher than expected 282 TPS2AdaptLoMin Learned closed throttle value of TPS sensor range lower than expected 242 TPS2RangeHigh TPS sensor voltage out of range high normally set if the TPS signal has shorted to power or ground for the sensor has opened 232 TPS2RangeLow TPS sensor voltage out of range low normally set if TPS signal has shorted to ground circuit has opened or sensor has failed 222 TPS_Sensors_Conflict TPS sensors differ by more than expected amount NOTE The TPS is not a serviceable item and can only be repaired by replacing the DV EV throttle assembly 291 Buck s Engines 66 Manual 36548 PG 08 Engine Control System for GM 8 1
86. sing the fuel pressure enriches the air fuel mixture Control is achieved by modulating the fuel trim valves Speed Management Drive by wire refers to the fact that the PG 08 control system has no throttle cable from the speed input device to the throttle body Instead the SECM is electronically connected both to the speed request signal and the throttle body The SECM monitors the speed input device position and controls the throttle plate by driving a DC motor connected to the throttle The DC motor actuates the throttle plate to correspond to the torque demand from the governor position The SECM will override the torgue speed command above a maximum engine speed and below a minimum idle speed The use of electronic throttle control ETC ensures that the engine receives only the correct amount of throttle opening for any given situation greatly improving idle quality and drivability Two throttle position sensors TPS1 and TPS2 which are integral to the drive by wire DBW throttle assembly provide feedback for position control by monitoring the exact position of the throttle valve See Figure 11 SECM self calibration and cross checking compares both signals and then checks for errors Figure 11 Throttle Position Sensor TPS on DV E5 Throitle NOTE The DV E5 throttle is not a serviceable assembly If a TPS sensor fails the assembly should be replaced Buck s Engines 23 Manual 36548 PG 08 Engine Control
87. ssureFault Low engine oil pressure Check battery and charging system voltage Check battery voltage during starting and when the engine is running Check voltage regulator alternator and charging system SysVoltRangeHigh DelayedEngine Check battery and wiring System voltage too high Shutdown for overheating and damage Measure battery power at SECM with a multimeter with key on SECM Pin A23 DRVP to SECM Pin A16 DRVG SECM Pin A23 DRVP to SECM Pin B17 DRVG Buck s Engines 74 Manual 36548 PG 08 Engine Control System for GM 8 1L Table 2 Diagnostic Fault Codes Flash Codes cont d FAULT CORRECTIVE ACTION PROBABLE FAULT ACTIONS FIRST CHECK SensVoltRangeLow Sensor reference voltage XDRP too low SensVoltRangeHigh Sensor reference voltage XDRP too high HardOverspeed Engine speed has exceeded the third level 3 of 3 of overspeed protection MediumOverspeed Engine speed has exceeded the second level 2 of 3 of overspeed protection SoftOverspeed Engine speed has exceeded the first level 1 of 3 of overspeed protection APP1RangeHigh APP sensor voltage out of range high normally set if the APP signal has shorted to power or the ground for the sensor has opened EngineShutdown EngineShutdown 1 HardRevLimit 2 EngineShutdown MediumRevLimit SoftRevLimit Measure transducer power at the TMAP connector with a multimeter TMAP Pin 3 PWR to TMAP Pin 1 s
88. st HEGO HEGO sensors sensor Buck s Engines 79 Manual 36548 Buck s Engines PG 08 Engine Control System for GM 8 1L THIS PAGE INTENTIONALLY LEFT BLANK 80 Manual 36548 PG 08 Engine Control System for GM 8 1L Chapter 8 Parts Description Fuel System Components The chart below lists the PG 08 components required for a 8 1L engine operating on natural gas fuel Engine Control Module SECM 48 pin P anion ois IT 4601 3009 D100 Venturi Mixer 1 6945 5017 Throttle DV E5 68mm 1 Throttle Hose 1 840 350 Hose Clamps 2 Buck s Engines 81 Manual 36548 PG 08 Engine Control System for GM 8 1L Maxitrol 210DZ Regulator This 210DZ regulator is supplied from an outside vendor as a complete assembly It has no serviceable parts If it tests defective replace the entire regulator with the specified replacement assembly The Maxitrol regulator is specifically engineered for the PG 08 system and cannot be replaced by a standard Maxtirol 210DZ regulator NOTE The PG 08 system will malfunction if the incorrect regulator is substituted in the system Please contact Buck s Engines for the correct replacement part Swing Radius 5 7 16 138 1mm Dimension A 9 228 6mm Dimension B 7 177 8mm Dimension C 6 152 4mm Dimension D 2 3 8 60 3mm Buck s Engines 82 Manual 36548 PG 08 Engine Control System for GM 8 1L ACFM Actual cubic feet
89. t Soak lt 257 F 125 C 8 16 Vdc Operating Voltage SECM microprocessor may reset at voltages below 6 3 Vdc On engine mounting underhood Operating Environment automotive Capable of withstanding spray from a pressure washer Buck s Engines 27 Manual 36548 PG 08 Engine Control System for GM 8 1L Fuel Trim Valve FTV Specifications Ignition System Specifications Buck s Engines 28 Manual 36548 PG 08 Engine Control System for GM 8 1L Chapter 3 Recommended Maintenance x EE EE OE AE EE EE EL N Suggested maintenance requirements for an engine equipped with an PG 08 fuel system are contained in this section The operator should however develop a customized maintenance schedule using the requirements listed in this section and any other requirements listed by the engine manufacturer Maintenance Tests amp Inspections Test Fuel System for Leaks e Obtain a leak check squirt bottle or pump spray bottle e Fill the bottle with an approved leak check solution e Spray a generous amount of the solution on the fuel system fuel lines and connections starting at the storage container e Wait approximately 15 60 seconds then perform a visual inspection of the fuel system Leaks will cause the solution to bubble e Listen for leaks e Smell for natural gas odor which may indicate a leak e Repair any leaks before continuing e Crank the engine through several revolutions This will energize the f
90. t in fault diagnostics Detected system faults can be displayed by the Malfunction Indicator Lamp MIL as Diagnostic Fault Codes DFC or flash codes and viewed in detail with the use of the Service Tool software When the ignition key is turned on the MIL will illuminate and remain on until the engine is started Once the engine is started the MIL lamp will go out unless one or more fault conditions are present If a detected fault condition exists the fault or faults will be stored in the memory of the small engine control module SECM Once an active fault occurs the MIL will illuminate and remain ON This signals the operator that a fault has been detected by the SECM Reading Diagnostic Fault Codes All PG 08 fault codes are three digit codes When the fault codes are retrieved displayed the MIL will flash for each digit with a short pause 0 5 seconds between digits and a long pause 1 2 seconds between fault codes A code 12 is displayed at the end of the code list EXAMPLE A code 461 ETCSticking has been detected and the engine has shut down and the MIL has remained ON When the codes are displayed the MIL will flash four times 4 pause then flash six times 6 pause then flash one time 1 This identifies a four sixty one 461 which is the ETCSticking fault If any additional faults were stored the SECM would again have a long pause then display the next fault by flashing each digit Since no other faults were stored the
91. talyst oxygen sensor can cause the sensor output to be effected due to exhaust pulsation entraining air upstream Repair any all leaks found Ensure the length from the post catalyst sensor to tailpipe is the same as original factory e Ensure that wire routing for the oxygen sensors is still keeping wires away from the exhaust system Visually inspect the oxygen sensors to detect any damage Buck s Engines 31 Manual 36548 PG 08 Engine Control System for GM 8 1L Maintenance Schedule NOTE The PG 08 fuel system was designed for use with natural gas fuel that contains a minimum of 55 methane with an energy content from 900 to 1550 BTU ft 3 Use of non compliant natural gas fuel may require more frequent service intervals and will disqualify the user from warranty claims INTERVAL HOURS CHECK POINT Every 250 Every 500 Every Every Every Hours or 1 Hours or 1009 1500 2300 Hours or Hours or Hours or month 3 months 6 months 9 months 1 year General Maintenance Test fuel system for leaks Prior to any service or maintenance activity Inspect engine for fluid leaks Inspect all vacuum lines and fittings Inspect electrical system check for loose dirty or damaged wires and connections Inspect isolation mounts on engine control module for cracks and wear replace as necessary eee tet hoses EER DI travel and operation Check for MIL lamp test at key on If MIL lamp remains
92. uel lock off and allow fuel to flow to the pressure regulator Apply additional leak check solution to the regulator converter fuel connections and housing Repeat leak inspection as listed above e Repair any fuel leaks before continuing Inspect Engine for Fluid Leaks e Start the engine and allow it to reach operating temperatures e Turn the engine off e Inspect the entire engine for oil and or coolant leaks e Repair as necessary before continuing Inspect Vacuum Lines and Fittings e Visually inspect vacuum lines and fittings for physical damage such as brittleness cracks and kinks Repair replace as required e Solvent or oil damage may cause vacuum lines to become soft resulting in a collapsed line while the engine is running e f abnormally soft lines are detected replace as necessary Inspect Electrical System e Check for loose dirty or damaged connectors and wires on the harness including fuel lock off TMAP sensor O2 sensors electronic throttle control relays fuel trim valves crank position sensor and cam position sensor e Repair and or replace as necessary Buck s Engines 29 Manual 36548 PG 08 Engine Control System for GM 8 1L Inspect Coolant Hoses e Visually inspect coolant hoses and clamps Remember to check the two coolant lines that connect to the pressure regulator e Replace any hose that shows signs of leakage swelling cracking abrasion or deterioration Inspect Battery System e Cle
93. ury A CAUTION indicates a potentially hazardous situation which if not avoided could result in damage to equipment or property A NOTE provides other helpful information that does not fall under the warning or caution categories Buck s Engines reserves the right to update any portion of this publication at any time Information provided by Buck s Engines is believed to be correct and reliable However no responsibility is assumed by Buck s Engines unless otherwise expressly undertaken Manual 36548 PG 08 Engine Control System for GM 8 1L Contents N REGULATORY COMPLIANCE sees ins se ese Gees ie Ned es Ne gen sie eeu ee en Ge Reneke ei 6 EPA CARB Emissions Certification ie sesse ee ee ee eke de Re Re ee ke ke eke 6 North American Compliance iese ee Re RA Re ek Re ee Re ke ee ee 6 ELECTROSTATIC DISCHARGE AWARENESS eeuse ee ee esse ee ee ee see ee ee ee ee ee ke 7 CHAPTER 1 SYSTEM OVERVIEW sees ss aasias is see ski sees kis wie seek bee siek see kk SEGE 8 PG 08 General Description ee ee RA RA AA AA AR Re ee anai aRt 8 PG 08 System Component sesse ee ek Re RA ke ke Re Re ee Re ee ee 10 Key Components ee ee ee aaan RA Re AA ke AA ee aiaia 10 PG 08 System Features iures see ee de AA Re ee Re ee ee AA ee ee ee 10 Natural Gas Fuel System OperatiON iese ee ee ee RA Re Re Re ke ee ee 12 PG 08 Electric Fuel LOCK Off ccccceeeeeeceneeeeeeeeeeeeeseaeeeeeeeeeeaeeteneeeeeaeeees 12 Fuel FOT o
94. uts Key Components The PG 08 system functions primarily on engine components that affect engine emissions and performance These key components include the following e Engine Combustion chamber design e Intake Exhaust valve configuration timing and lift e Intake Exhaust manifold design e Catalytic converter and exhaust system e Throttle body e Air intake and air filter e Gaseous fuel mixer e Gaseous fuel pressure regulator e Fuel trim valve e Small engine control module SECM firmware and calibration e Fuel system sensors and actuators e Ignition system including spark plugs cables coils and drivers PG 08 System Features The PG 08 system uses an advanced speed density control strategy for fuel spark and air throttle control Key features include the following e Speed load spark control with tables for dwell timing and fuel type e Speed load throttle control with table for maximum TPS limiting e Closed loop fuel control with two oxygen sensors one installed pre catalyst and one installed post catalyst The pre catalyst oxygen sensor includes adaptive learn to compensate for fuel or component drift The post catalyst oxygen sensor includes adaptive learn to compensate the pre catalyst oxygen sensor setting for pre catalyst oxygen sensor drift and catalyst aging The pre catalyst oxygen sensor function includes parameters for transport delay O set point excursion rich lean jump back rich lean and perturbatio
95. vice Manual Related MIL Faults Pre catalyst O2 sensor faults Low side driver Trim valve duty cycle EST faults Fuel adapt faults Low coolant temperature Buck s Engines 53 Manual 36548 PG 08 Engine Control System for GM 8 1L Basic Troubleshooting cont d High Idle Speed Engine idles above the range of 750 1000 rpm PRELIMINARY CHECKS Perform the visual checks as described at start of Basic Troubleshooting chapter PROBABLE CAUSE CORRECTIVE ACTION Check all hoses and gaskets for cracking kinks or leaks Incorrect idle speed control Verify that there are no vacuum leaks See Chapter 7 Advanced Diagnostics amp Chapter 5 Tests and Adjustments ee Replace throttle Throttle sticking See Fault Code 461 ETC_Sticking Check APP function with Service Tool Speed input device sticking or Verify smooth change of APP reading with incorrect speed signal potentiometer movement See Chapter 7 Advanced Diagnostics Check for vacuum hose leak Engine mechanical Check for PCV malfunction Check for defective intake gasket Related MIL Faults ETC Sticking fault Idle adapt out of range MAP Sticking fault MAP high value Buck s Engines Manual 36548 PG 08 Engine Control System for GM 8 1L Basic Troubleshooting cont d Excessive Exhaust Emissions or Odors Engine has high CO emissions NOTE Excessive odors do not necessarily indicate excessive emissions PRELIMINARY CHECKS
96. xer 210DZ Regulator Service Testing To check the 210DZ regulator operation the following hardware is reguired 1 Shop air pressure regulator adjusted to 0 5 psi Shop air hose fitting 1 4 NPT to air hose Air hose Test gauge fitting 3 4 NPT x 1 4 hose barb Vacuum hose or vinyl tubing 0 15 WC Magnehelic gauge inches of water column Dapy Figure 19 Regulator Pressure Test Connections Buck s Engines 38 Manual 36548 PG 08 Engine Control System for GM 8 1L Regulator Pressure Test Procedure Refer to Figure 19 1 Field fabricate a fitting for the outlet of the regulator that will allow pressure measurement It needs to prohibit gas flow with the exception of a tiny 5 64 orifice This can be drilled anywhere in the test fitting Attach a Magnehelic gauge to the outlet of the Maxitrol regulator Connect a compressed air line shop air 0 5 psi to the natural gas fuel inlet of the 210DZ regulator The static pressure should read between 0 15 0 35 inH20 on the Magnehelic gauge If the pressure reading begins to increase a leak is most likely present at the valve seat either the valve or the valve itself If a leak is present the regulator should be replaced If the test is successful reinstall per engine packager instructions The 210DZ primary stage pressure can also be tested at idle on a running engine The 210DZ outlet pressure should be between 0 15 0 35 inH 0 at 900 rpm idle
97. ys The energized main power relays supply 12 Vdc power to the heated element of the oxygen sensors fuel lock off fuel trim valve FTV crank sensor cam sensor and the ignition coils The SECM supplies voltage to the electronic throttle actuator oil pressure switch fuel temperature sensor and the coolant temperature sensor Transducer or sensor power 5 Vdc is regulated by the SECM and supplied to the manifold temperature air pressure TMAP sensor throttle position sensor TPS and the accelerator pedal position sensors APP1 amp APP2 The SECM provides a transducer ground for all the sensors and a low side driver signal controlling the fuel lock off MIL and FTV Fuel Management During engine cranking at startup the SECM provides a low side driver signal to the fuel lock off which opens the lock off allowing natural gas to flow to the 210DZ regulator A stall safety shutoff feature is built into the SECM to close the lock off in case of a stall condition The SECM monitors three engine states Crank when the crankshaft position sensor detects any engine revolutions Stall when the key is in the ON position but the crankshaft position sensor detects no engine revolutions Run state when the engine reaches pre idle RPM When an operator turns on the key switch the lock off is opened but if the operator fails to crank the engine the SECM will close the lock off after about 5 seconds To maintain proper exhaust emission

View/Print Brochure

Contents

Download Pdf Manuals

Related Search

Related Contents