Detonation/Spark-Knock/Pings

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 Spark Controls.

Lean Air-Fuel mixture Check fuel pressure.
Check Air-Fuel ratio.
Check O2 sensor output.
Perform injector balance test (MPI only).

EGR malfunction Check EGR system.

Poor or contaminated fuel Recommend higher grade fuel