TROUBLE DIAGNOSES — Diagnostic Table (Cont'd) — Symptom & Condition 24: Backfire through the intake
EF & EC-62flowchartDiagnostic Table (Cont'd)
SYMPTOM & CONDITION 24 — Backfire through the intake
Possible Causes Matrix — Symptom 24: Backfire through the intake
SPECIFICATIONS
Possible CausesMixture ratio (too lean)
1O
2
3O
4
5O
6O
7
SPECIFICATIONS
Possible CausesIgnition timing (too retarded)
1
2O
3
4
5
6
7
FUEL SYSTEM
Possible CausesInjectors (clogged)
1
2
3
4O
5
6
7
INTAKE SYSTEM
Possible CausesAir duct (air leaks)
1O
2
3
4
5
6
7
INTAKE SYSTEM
Possible CausesIntake manifold (gaskets) (air leaks)
1O
2
3
4
5
6
7
CONTROL SYSTEM
Possible CausesAir flow meter
1
2
3
4
5
6
7O
CONTROL SYSTEM
Possible CausesExhaust gas sensor
1
2
3
4
5O
6O
7
SERVICE PROCEDURE
Service Procedure Flowchart — Symptom 24: Backfire through the intake
1
CHECK 1: Check intake system for air leaks. (Engine / Air duct — Leak) [SEF301G]
N.G.
N.G. — Repair/replace the part.
O.K.
2
CHECK 2: Check ignition timing. (Timing light) [SEF284G]
N.G.
N.G. — Adjust ignition timing. [See page EF & EC-22.]
O.K.
3
REMOVE 3: Remove vacuum hose from pressure regulator, and try to drive. [SEF291G]
Improved
Improved — Check idle mixture ratio. [See page EF & EC-25.]
No change
4
No change — proceed to step 5
5
PERFORM 5: Self-diagnosis Mode II — Check mixture ratio by flashes of inspection lamps. (9 times or more/10 sec. at 2,000 rpm) [SEF373G]
O.K.
CHECK 7: Perform self-diagnosis Mode III and V (for air flow meter). [SEF285G] (Self-diagnosis Mode III / Self-diagnosis Mode V)
N.G.
6
N.G. — proceed to step 6
7
DISCONNECT 6: Disconnect exhaust gas sensor connector, and try to drive. [SEF307G]
No change
No change — Check idle mixture ratio. [See page EF & EC-25.]
Improved
Improved — Replace the sensor.