TROUBLESHOOTING
Contents
1. CHECK SPARK PLUGS Plug gap 1 1 mm 0 043 in HINT Check compression pressure and valve clearance if necessary OK CHECK COLD START INJECTOR See page Fl 54 CONTINUED ON PAGE FI 15 Malfunction code s BAD BAD NO NO NO BAD Diagnostic code s See page Fl 26 1 Oil filler cap 2 Oil dipstick 3 Hose connections 4 PCV hoses 5 EGR system EGR valve stays open Element Clean or replace ISC system 1 Wiring connections 2 ISC valve See page FI 73 3 ECU Ignition timing Adjust See page IG 12 1 Spark plugs and high tension cords 2 Compression pressure Minimum 9 0 kg cm2 128 psi 883 kPa at 250 rpm 3 Valve clearance Cold Standard IN 0 15 0 25 mm 0 006 0 010 in EX 0 20 0 30 mm 1 Cold start injector See page FI 54 2 Cold start injector time switch See page Fl 78 EFI SYSTEM OK CONTINUED FROM PAGE FI 14 CHECK FUEL PRESSURE BAD See page FI 49 OK CHECK INJECTORS BAD See page FI 59 OK CHECK EFI ELECTRONIC CIRCUIT BAD USING VOLT OHMMETER See page FI 29 FI 15 Troubleshooting 1 Fuel pump See page FI 48 2 Fuel filter 3 Fuel pressure regulator See page FI 57 Injection condition Wiring connections Power to ECU 1 Fusible links 2 Fuses 3 EFI main relay See page FI 76 Air flow meter See page FI 66 Water temp sensor See page FI 79 Air temp sensor2. See page FI 66 Injection signal circuit 1 Injector wiring 2 ECU See page FI 85 FI 16 EFISYSTEM Troubleshooting SYMPTOM HIGH ENGINE IDLE SPEED NO DROP CHECK ACCELERATOR LINKAGE SAD OK CHECK DIAGNOSIS SYSTEM Malfunction Diagnostic code s See page FI 26 Check for output of diagnostic code code s See page R 22 Normal code CHECK ISC SYSTEM 1 Wiring connections BAL 2 ISC valve See page FI 72 3 Air conditioner switch OK CHECK THROTTLE POSITION Throttle body SENSOR See page FI 68 BAND OK CHECK FUEL PRESSURE Fuel pressure regulator High pressure See page FI 49 BAND CHECK COLD START INJECTOR Cold start injector Linkage See page FI 54 BAD A OK CHECK INJECTORS See page FI 59 BAD Injectors Leakage Injection quantity OK CHECK EFI ELECTRONIC CIRCUIT 1 Wiring connection USING VOLT OHMMETER BAD 2 Power to ECU See page FI 29 1 Fusible links 2 Fuses 3 EFI main relay See page FI 76 3 Air flow meter See page FI 66 4 Water temp sensor See page FI 79 5 Air temp sensor See page FI 66 6 Injector signal circuit 1 Injector wiring 2 ECU See Fl 17 EFISYSTEM Troubleshooting SYMPTOM ENGINE BACKFIRES Lean Fuel Mixture Misfire CHECK DIAGNOSIS SYSTEM Check for output of diagnostic code Diagnostic code s See page FI 26 Malfunction See page Fl 22 POUS Normal code CHECK FOR VACUUM LEAKS I
3. Check for output of diagnostic code E p See page Fl 22 cece Normal code CHECK IGNITION SPARK 1 High tension cords See page IG 5 BAG 2 Distributor 3 Ignition coil 4 Igniter CHECK IGNITION TIMING NO Ignition timing Adjust See page IG 12 1 Connect terminals TE1 and E1 of the check connector 2 Check ignition timing Standard 10 BTDC idle w Terminals TE1 and E1 connected CHECK FUEL PRESSURE BAD 1 Fuel pump See page Fl 48 See page FI 49 2 Fuel filter 3 Fuel pressure regulator See page FI 57 OK CHECK INJECTORS SAG Injection condition See page FI 59 OK CONTINUED ON PAGE FI 20 FI 20 EFISYSTEM Troubleshooting OK CONTINUED FROM PAGE FI 19 CHECK SPARK PLUGS Plug gap 1 1 mm 0 043 in HINT Check compression pressure and valve clearance if necessary Spark plugs Compression pressure Minimum 9 0 kg cm2 0 28 psi 883 kPa f at 250 rpm Valve clearance Cold Standard IN 0 15 0 25 mm 0 006 0 010 in EX 0 20 0 30 mm NO CHECK EFI ELECTRONIC CIRCUIT Wiring connections USING VOLT OHMMETER BAD Power to ECU See page FI 29 1 Fusible links 2 Fuses 3 EFI main relay See page FI 76 Air flow meter See page FI 66 Water temp sensor See page FI 79 Air temp sensor See page FI 66 Throttle position sensor See page FI 68 Injection signal circuit 1 Injector wiring
4. FI 9 EFISYSTEM Troubleshooting TROUBLESHOOTING TROUBLESHOOTING HINTS 1 Engine troubles are usually not caused by the EFI system When troubleshooting always first check the condition of the other systems a Electronic source e Battery Fusible links Fuses b Body ground e Fuel supply e Fuel leakage e Fuel filter e Fuel pump d Ignition system e Spark plugs e High tension cords e Distributor e ignition coil Igniter e Air induction system e Vacuum leaks f Emission control system e PCV system e EGR system g Others e ignition timing ESA system e Idle speed ISC system etc 2 The most frequent cause of problems is simply a bad contact in wiring connectors Always check that connections are secure When inspecting the connector pay particular attention to the following points a Check to see that the terminals are not bent b Check to see that the connector is pushed in completely and locked c Check to see that there is no signal change when the connector is slightly tapped or wiggled 3 Troubleshoot sufficiently for other causes before replacing the ECU as the ECU is of high quality and it is expensive FI 10 EFI SYSTEM Troubleshooting Digital Type Analog Type 4 Use a volt ohmmeter with high impedance 10 kQ V mini mum for troubleshooting of the electrical circuit See page FI 29 TROUBLESHOOTING PROCEDURES SYMPTOM DIFFICULT TO START OR NO START ENG
5. INE WILL NOT CRANK OR CRANKS SLOWLY CHECK ELECTRIC SOURCE 1 Battery 1 Connection 2 Gravity Drive belt Charging system 3 Voltage 2 Fusible links BAD CHECK STARTING SYSTEM 1 Ignition switch 2 Starter relay USA only 3 Starter 4 Neutral start switch 5 Wiring Connection SYMPTOM DIFFICULT TO START OR NO START CRANKS OK CHECK DIAGNOSIS SYSTEM Check for output of diagnostic code See page Fl 22 BAD Diagnostic code s Malfunction See page FI 26 code s Normal code DOES ENGINE START WITH ISC system ACCELERATOR PEDAL 7 1 ISC valve DEPRESSED 2 Wiring connection NO CHECK FOR VACUUM LEAKS IN AIR 1 Oil filler cap BAD ae INTAKE LINE 2 Oil dipstick 3 Hose connections 4 PCV hoses 5 EGR system EGR valve stays open CHECK IGNITION SPARK DAD High tension cords See page IG 5 Distributor Ignition coil Igniter OK CONTINUED ON PAGE FI 11 EFI SYSTEM OK CONTINUED FROM PAGE FI 10 CHECK SPARK PLUGS Plug gap 1 1 mm 0 043 in NO HINT Check compression pressure and valve clearance if necessary BAD All Plugs WET CHECK FUEL SUPPLY TO INJECTOR 1 Fuel in tank BAD 2 Fuel pressure in fuel line 1 Connect terminals B and FP of the check connector 2 Fuel pressure at fuel return hose can be felt See CHECK FUEL PUMP SWITCH IN AIR FLOW METER BAD Check continuity between terminals FC and E1 while me
6. N AIR ree 1 Oil filler cap INTAKE LINE 2 Oil dipstick 3 Hose connections 4 PCV hose s 5 EGR system EGR valve stays open CHECK IGNITION TIMING NO Ignition timing Adjust See page IG 12 1 Connect terminals TE1 and E1 of the check connector 2 Check ignition timing Standard 10 BTDC idle w Terminals TE1 and E1 connected CHECK COLD START INJECTOR E 1 Cold start injector See page Fl 54 See page Fl 54 2 Cold start injector time switch See page Fl 78 CHECK FUEL PRESSURE BAD 1 Fuel pump See page Fl 48 3 Fuel pressure regulator See page FI 57 OK CHECK INJECTORS ne Injectors Clogged See page FI 59 OK CHECK EFI ELECTRONIC CIRCUIT TE Wiring connection USING VOLT OHMMETER Power to ECU 1 Fusible links 2 Fuses 3 EFI main relay See page FI 76 Air flow meter See page FI 66 Water temp sensor See page FI 79 See page FI 29 Air temp sensor See page FI 66 Throttle position sensor See page FI 68 Injection signal circuit 1 Injector wiring 2 Fuel cut RPM See page FI 88 3 ECU See page FI 85 FI 18 EFISYSTEM Troubleshooting SYMPTOM MUFFLER EXPLOSION AFTER FIRE Rich Fuel Mixture Misfire CHECK DIAGNOSIS SYSTEM Check for output of diagnostic code See page Fl 22 Normal code Diagnostic code s See page Fl 26 p Malfunction code s CHECK IGNITION TIMING NO Ignition timing Adjust See page IG 12 1 Connect terminals TE1 and E1 of the c
7. S IN AIR Oil filler cap INTAKE LINE BAD _ Oil dipstick Hose connections PCV hoses EGR system EGR valve stays open OK CHECK FUEL SUPPLY TO INJECTOR Fuel line Leakage Deformation BAD 1 Fuel in tank Fuses 2 Fuel pressure in fuel line Fuel pump See page FI 48 1 Connect terminals Band FP Fuel filter of the check connector Fuel pressure regulator See page FI 57 2 Fuel pressure at fuel return hose can be felt See page FI 49 OK CHECK AIR FILTER ELEMENT a Element Clean or replace OK CHECK IDLE SPEED ISC system Standard 700 rpm BAD 1 Wiring connections 2 ISC valve See page FI 73 3 ECU Test by substitution CHECK IGNITION TIMING Ignition timing Adjust See page IG 12 1 Connect terminals TE1 and E1 of the service connector 2 Check ignition timing Standard 10 BTDC idle w Terminals TE1 and El connected CHECK SPARK PLUGS 1 Spark plugs Plug gap 1 1 mm 0 043 in 2 Compression pressure HINT Check compression pressure Minimum 9 0 kg cm2 and valve clearance if necessary 128 psi 883 kPa at 250 rpm 3 Valve clearance Cold Standard IN 0 15 0 25 mm 0 006 0 010 in OK CONTINUED ON PAGE FI 13 FI 13 EFISYSTEM Troubleshooting OK CONTINUED FROM PAGE FI 12 1 Cold start injector See page FI 54 CHECK COLD START INJECTOR See page FI 54 BAD 2 Cold start injector time switch See page Fl 78 RECHECK FUEL PRESSURE EAD 1 Fuel p
8. asuring plate of air flow meter is open CHECK IGNITION TIMING 1 Connect terminals TE1 and E1 of the NO check connector 2 Check ignition timing Standard 10 BTDC idle w Terminals TE1 and E1 connected CHECK EFI ELECTRONIC CIRCUIT USING VOLT OHMMETER BAD See page FI 29 FI 11 Troubleshooting Spark plugs Compression pressure Minimum 9 0 kg cm2 128 psi 883 kPa at 250 rpm Valve clearance Standard IN 0 15 0 25 mm 0 006 0 010 in EX 0 20 0 30 mm 0 008 0 012 j Injector s Shorted or leaking 2 Injector wiring Short circuited 3 Cold start injector Leakage See page FI 54 4 Cold start injector time switch See page FI 78 Fuel line Leakage Deformation Fuse Fuel pump See page FI 48 Fuel filter Fuel pressure regulator See page FI 57 oR ON Air flow meter See page FI 66 Ignition timing Adjust See page IG 12 1 Wiring connection 2 Power to ECU 1 Fusible links 2 Fuses 3 EFI main relay See page FI 76 3 Air flow meter See page FI 66 4 Water temp sensor See page FI 79 5 Air temp sensor See page FI 66 6 Injection signal circuit 1 Injector wiring FIl 12 EFISYSTEM Troubleshooting SYMPTOM ENGINE OFTEN STALLS CHECK DIAGNOSIS SYSTEM anag Diagnostic code s See page FI 26 Check for output of diagnostic code MR See page Fl 22 Normal code CHECK FOR VACUUM LEAK
9. heck connector 2 Check ignition timing Standard 10 BTDC idle w Terminals TE1 and E1 connected 1 Cold start injector See page FI 54 2 Cold start injector time switch See page FI 78 CHECK COLD START INJECTOR See page FI 54 BAD OK CHECK FUEL PRESSURE ae Fuel pressure regulator See page FI 57 See page FI 49 OK CHECK INJECTORS See page FI 59 Injectors Leakage OK CHECK SPARK PLUGS Plug gap 1 1 mm 0 043 in HINT Check compression pressure and valve clearance if necessary 1 Spark plugs 2 Compression pressure Minimum 9 0 kg cm2 128 psi 883 kPa at 250 rpm 3 Valve clearance cold Standard IN 0 15 0 25mm 0 006 0 010 in EX 0 20 0 30 mm 0 008 0 012 in NO CHECK EFI ELECTRONIC CIRCUIT 1 Throttle position sensor USING VOLT OHMMETER 2 Injection signal circuit See page FI 29 1 Injector wiring 2 Fuel cut RPM See page FI 88 3 ECU See page FI 85 3 Oxygen sensor s See pages Fl 82 84 FI 19 EFISYSTEM Troubleshooting SYMPTOM ENGINE HESITATES AND OR POOR ACCELERATION CHECK BRAKES BAD Brakes Drag OK CHECK FOR VACUUM LEAKS 1N AIR 1 Oil filler cap BAD INTAKE LINE 2 Oil dipstick 3 Hose connections 4 PCV hose s 5 EGR system EGR valve stays open OK CHECK AIR FILTER ELEMENT D Element Clean or replace OK CHECK DIAGNOSIS SYSTEM TR Diagnostic code s See page Fl 26
10. ump See page Fl 48 See page FI 49 2 Fuel filter 3 Fuel pressure regulator See page FI 57 OK CHECK INJECTORS BAD Injection condition See page FI 59 OK CHECK EFI ELECTRONIC CIRCUIT USING Dap 1 Wiring connections VOLT OHMMETER 2 Power to ECU 1 Fusible links 2 Fuses 3 EFI main relay See page FI 76 See page FI 29 3 Air flow meter See page Fl 66 4 Water temp sensor See page FI 79 5 Air temp sensor See page FI 66 6 Injection signal circuit 1 Injector wiring SYMPTOM ENGINE SOMETIMES STALLS CHECK DIAGNOSIS SYSTEM Malfunction Diagnostic code s See page Fl 26 Check for output of diagnostic code code s See page Fl 22 Normal code CHECK AIR FLOW METER BAD Air flow meter See page FI 66 OK CHECK WIRING CONNECTORS AND BAD 1 Connectors RELAYS 2 EFI main relay See page FI 76 3 Circuit opening relay See page FI 77 Check for signal change when the connecior or relay is slightly tapped or wiggled FI 14 EFI SYSTEM Troubleshooting SYMPTOM ROUGH IDLING AND OR MISSING CHECK DIAGNOSIS SYSTEM Check for output of diagnostic code See page Fl 22 Normal code CHECK FOR VACUUM LEAKS IN AIR INTAKE LINE OK CHECK AIR FILTER ELEMENT OK CHECK IDLE SPEED STD 700 rpm CHECK IGNITION TIMING 1 Connect terminals TE1 and E1 of the check connector 2 Check ignition timing Standard 10 BTDC idle w Terminals TE1 and E1 connected OK
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