Detonation/Spark-Knock/Pings

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


POSSIBLE CAUSE ACTION



Lean air/fuel mixture ^ Check computer controls. SEE Computers And Control Systems / Testing and Inspection . Testing and Inspection


Poor or contaminated fuel ^ Check for excessive alcohol content.

^ Recommend higher grade fuel.


Incorrect fuel pressure ^ Check fuel pressure.


Vacuum leak ^ Inspect vacuum hoses for proper routing and damaged lines.

^ Check intake manifold, throttle body, etc.