Detonation/Spark Knock

SYMPTOM
A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks that change with throttle opening.

CAUSE (BY SYSTEM/COMPONENT):

IGNITION SYSTEMS
- Spark plugs for correct heat range.
- Ignition timing.
- Distributor cap (if applicable) for arcing or carbon tracking inside cap.

FUEL SYSTEMS
- Fuel system for low pressure.
- For poor fuel quality, proper octane rating.

EMISSION SYSTEMS
- Check EGR valve for not opening.

ENGINE MECHANICAL
- For incorrect basic engine parts such as cam, heads, pistons, etc.
- Excessive oil entering combustion chamber.
- Carbon build-up on pistons or combustion chamber.
- Engine overheating.
- Turbo operation if applicable.