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 ACTION


EGR inoperative Check EGR system. Refer to TESTING PROCEDURES.



Ignition timing advanced Check Ignition Timing. Refer to COMPUTERS AND CONTROL SYSTEMS.




Spark timing not retarding Check Spark Controls. Refer to COMPUTERS AND CONTROL SYSTEMS.



Poor or contaminated fuel Recommend higher grade fuel