Detonation - Pings, Spark Knock

A mild to severe ping, usually worse under load or acceleration. Sounds like something is rattling or knocking in the engine.

POSSIBLE CAUSE ACTION




Spark timing not retarding Check Spark Controls,

Lean Air-Fuel mixture Check Air-Fuel ratio, O2 sensor, perform injector balance test, inspect regulator operation (check vacuum line and return hose), check fuel pressure

EGR malfunction Check EGR system, Exhaust Gas Recirculation

Thermostatic Air Cleaner (TAC) Check Thermostatic
malfunction Air Cleaner, Thermostatic Air Cleaner

Poor or contaminated fuel Recommend higher grade fuel