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
If OK, proceed to step 2
2. Check EGR electronic controls.



Initial timing incorrect Check Ignition Timing



Air damper door binding,
air cleaner temperature
control malfunction Check inlet air temperature system.


Spark timing not retarding Check Spark Controls (SC).



Poor or contaminated fuel Recommend higher grade fuel