FI-20 EFI SYSTEM — Troubleshooting SYMPTOM — MUFFLER EXPLOSION (AFTER FIRE) -Rich Fuel Mixture-Misfire CHECK DIAGNOSIS SYSTEM Check for output of diagnostic code. (See page FI-23) Malfunction code(s) Diagnostic code(s) (See page FI-26) Normal code 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] NO Adjust ignition timing (See page IG-20) OK CHECK COLD START INJECTOR (See page FI-77) BAD 1. Cold start injector 2. Cold start injector time switch (See page FI-112) OK CHECK INJECTORS BAD Injectors — Leakage OK CHECK SPARK PLUGS Plug gap: 7M-GE 1.1 mm (0.043 in.) 7M-GTE 0.8 mm (0.031 in.) — HINT — Check compression pressure and valve clearance if necessary. NO 1. Spark plugs 2. Compression pressure Minimum: 9.0 kg/cm² (128 psi, 883 kPa) at 250 rpm 3. Valve clearance Standard: IN 0.15 ~ 0.25 mm (0.006 ~ 0.010 in.) EX 0.20 ~ 0.30 mm (0.008 ~ 0.012 in.) OK CHECK EFI ELECTRONIC CIRCUIT USING VOLT/OHMMETER (See pages FI-30, 49) BAD 1. Throttle position sensor 2. Injection signal circuit (1) Injector wiring (2) Resistor (7M-GTE) (3) ECU 3. Oxygen sensor(s)