Detonation - Pings, Spark Knock

Symptom: A mild to severe ping, usually worse under load or acceleration. Sounds like something is rattling or knocking in the engine.

POSSIBLE CAUSE ACTION


Spark timing not retarding ^ Check timing and advance.
SEE IGNITION SYSTEM/ ADJUSTMENT PROCEDURES.


Lean Air-Fuel mixture ^ Check fuel pressure.

^ Check Air-Fuel ratio.

^ Check O2 sensor output.

^ Perform injector balance test (SFI only only).


EGR malfunction ^ Check EGR system


Thermostatic Air Cleaner (TAC) ^ SEE Thermostatic Air Cleaner


Poor or contaminated fuel ^ Recommend higher grade fuel