Detonation/Spark Knock/Pings

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

POSSIBLE CAUSE ACTION

Incorrect spark timing Check Spark Controls (EST, ESC ...etc). Chart C-5 Electronic Spark Control (ESC) Check



Poor or contaminated fuel Recommend higher grade fuel



Overheated engine Check coolant level, cooling fan and thermostat operation



Boost pressure too great Check boost control solenoid and bypass valve operation. Powertrain Controls - ECM/PCM



Inoperative EGR solenoid valve(s), Check EGR system.
plugged or restricted EGR exhaust Refer to EMISSION CONTROL DEVICES.
passages.