Toyota 3F-E - Engine Backfires - Lean Fuel Mixture

EFI SYSTEM — Troubleshooting
FI-17
SYMPTOM - ENGINE BACKFIRES-Lean Fuel Mixture
CHECK DIAGNOSIS SYSTEM
Diagnostic code(s) (See pages FI-24, 25)
Check for output of diagnostic code.
Malfunction
(See page FI-21)
code(s)
Normal code
CHECK FOR VACUUM LEAKS IN AIR
•
1. Oil filler cap
INTAKE LINE
BAD
2. Oil dipstick
3.
Hose connections
4.
PCV hose(s)
5.
EGR system — EGR valve stays open
OK
CHECK IGNITION TIMING
Ignition timing — Adjust (See page EM-11 )
1.
Connect terminals TE1 and El of the
NO
check connector.
2.
Check ignition timing.
Standard:
7
0
BTDC @ idle
(
w/ connected TE1 and
El)
OK
CHECK COLD START INJECTOR
•
1. Cold start injector (See page FI-50)
(See page FI-50)
BAD
2. Cold start injector time switch.
(See page FI-72)
OK
CHECK FUEL PRESSURE
•
1. Fuel pump (See page FI-44)
(See page FI-45)
BAD
2. Fuel filter
3.
Fuel pressure regulator (See page FI-53)
OK
CHECK INJECTORS
Injectors — Clogged
(See page FI-55)
BAD
OK
CHECK EFI ELECTRONIC CIRCUIT
1. Wiring connection
USING VOLT/OHMMETER
BAD
2. Power to ECU
(See page FI-27)
(1) Fusible links
(2)
Fuses
(3)
EFI main relay (See page FI-70)
3. Air flow meter (See page FI-62)
4. Water temp. sensor (See page FI-73)
5. Air temp. sensor (See page FI-62)
6. Throttle position sensor (See page FI-64)
7. Injection signal circuit
(1)
Injector wiring
(2)
Fuel cut RPM (See page FI-80)
(3)
ECU (See page FI-77)
8. Oxygen sensors (See page FI-75)
ill
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