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


EGR inoperative 1. Check EGR system under
TESTING PROCEDURES. If OK, step 2
2. Check EGR electronic controls.
Refer to COMPUTERIZED ENGINE CONTROLS.



Ignition timing advanced Check Ignition Timing under
ADJUSTMENT PROCEDURES.



Air damper door binding, Check Inlet Air Temperature System
air cleaner temperature under TESTING PROCEDURES.
control malfunction



Spark timing not retarding Check Spark Controls (SCC).
Refer to COMPUTERIZED ENGINE CONTROLS.



Poor or contaminated fuel Recommend higher grade fuel