Detonation -- Pings and Spark Knocks

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

POSSIBLE CAUSE
EGR inoperative

ACTION
Check EGR system. Exhaust Gas Recirculation



POSSIBLE CAUSE
Ignition timing advanced

ACTION
Check Ignition Timing.



POSSIBLE CAUSE
Spark timing not retarding.

ACTION
Check Spark Controls.



POSSIBLE CAUSE
Poor or contaminated fuel.

ACTION
Recommend higher grade fuel