Detonation, Spark Knock

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 (if A/C equipped).
^ Proper cooling fan operation
^ Front air dam missing or damaged.

Check:
^ Knock sensor circuit system for no spark retard, during the knock condition
^ TCC operation
^ EGR operation
^ Proper fuel pressure

Remove carbon with top engine cleaner:

^ Check for excessive oil in combustion chamber.
^ Check for poor fuel quality, proper octane rating.

Fuel with higher octane ratings can eliminate problem.

With ignition On and engine not running, view knock too long status using a Scan tool. This status can be viewed on the Saturn PDT in the spark control table. If this parameter indicates "Yes" the PCM should be replaced. If "Yes" is indicated with engine running at idle and no engine noise is present the PCM is faulty.