Detonation/Spark Knock

Definition: A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks that change with throttle opening. Sounds like popcorn popping.

^ Check for obvious overheating problems:

^ Low coolant.

^ Loose water pump belt.

^ Restricted air flow to radiator, or restricted water flow through radiator.

^ Inoperative electric cooling fan circuit. See CHART C-12.

^ Check ignition timing. See Vehicle Emission Control Information label.

^ Check EGR system for not opening - CHART C-7 or C-7A.

^ Check ESC system for no retard - see CHART C5.

^ Check fuel system pressure. See CHART A-7.

^ Remove carbon with top engine cleaner. Follow instructions on can.

^ Check for correct PROM. (See Service Bulletins)

^ Check for leaking valve oil seals.

^ Check for improper operation of transmission and TCC.

^ Check for incorrect basic engine parts such as cam, heads, pistons, etc.

^ Check for poor fuel quality, proper octane rating.