Operation CHARM: Car repair manuals for everyone.

Detonation, Spark Knock

DEFINITION: A mild to severe ping, usually worse under acceleration. It sounds like popcorn popping.

Check for overheating problems:
^ Low coolant
^ Loose drive belt
^ Restricted air flow through radiator, or restricted air flow through condenser
^ Proper cooling fan(s) operation
^ Front air dam missing or damaged

Check:
^ Knock sensor circuit system for no spark retard, during the knock condition
^ TCC operation (automatic transaxle only)

Remove carbon with top engine cleaner:
^ Check to see if engine is running lean (monitor long term fuel trim for significant positive values). Refer to P0171. P0171
^ Check for poor fuel quality, proper octane rating

Fuel with higher octane ratings may eliminate problem