Operation CHARM: Car repair manuals for everyone.
Manuals through 2025 now available!

Our trusted friends have launched a new website named LEMON, which has newer manuals. It also contains all the CHARM manuals.

LEMON is the spiritual successor to CHARM, I recommend you try it!

Link: lemon-manuals.la or lemon-manuals.org.ua

(Some people have issue connecting. LEMON is investigating. For now, use Firefox or change your DNS server)

Or, hide this message: temporarily or permanently

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