FI/EFI System — Symptom — Engine BACKFIRES-Lean Fuel Mixture, page 19

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)