EFI SYSTEM — Troubleshooting FI-19 SYMPTOM — ENGINE BACKFIRES-Lean Fuel Mixture CHECK DIAGNOSIS SYSTEM (Check for output of diagnostic code. (See page FI-23) Normal code CHECK FOR VACUUM LEAKS IN AIR INTAKE LINE OK CHECK IGNITION TIMING 1. Connect terminals TE1 and E1 of the check connector. 2. Check ignition timing. STD: 10° BTDC @ idle (w/ connect terminals TE1 and E1) OK CHECK COLD START INJECTOR (See page FI-77) OK CHECK FUEL PRESSURE (See page FI-71) OK CHECK INJECTORS (See page FI-83) OK CHECK EFI ELECTRONIC CIRCUIT USING VOLT/OHMMETER (See pages FI-30, 49) Malfunction code(s) BAD NO BAD BAD BAD BAD Diagnostic code(s) (See page FI-26) 1. Oil filler cap 2. Oil dipstick 3. Hose connections 4. PCV hoses Adjust ignition timing (See page IG-20) 1. Cold start injector 2. Cold start injector time switch (See page FI-112) 1. Fuel pump (See page FI-70) 2. Fuel filter 3. Fuel pressure regulator (See page FI-81) Injectors — Clogged 1. Wiring connection 2. Power to ECU (1) Fusible links (2) Fuses (3) EFI main relay 3. Air flow meter 4. Water temp. sensor 5. Air temp. sensor 6. Throttle position sensor 7. Injection signal circuit (1) Injection wiring (2) Resistor (7M-GTE) (3) ECU (4) Fuel cut signal 8. Oxygen sensor(s)