Detonation - Pings, Spark Knock

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

POSSIBLE CAUSE ACTION




Ignition timing advanced Check base timing.
SEE Ignition System/ ADJUSTMENT PROCEDURES.

Spark timing not retarding Check with timing light.

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.
Testing and Inspection

Poor or contaminated fuel Recommend higher grade fuel