Operation CHARM: Car repair manuals for everyone.

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 advanced or not retarding ^ Check Spark Controls.


Lean Air-Fuel mixture ^ Check fuel pressure.

^ Check Air-Fuel ratio.

^ Check O2 sensor output.

^ Perform injector balance test (SFI only only).


Poor or contaminated fuel ^ Recommend higher grade fuel