Detonation/Spark Knock/Pings

SYMPTOM DESCRIPTION
A mild or severe ping, usually worse under acceleration. The engine makes a sharp metallic knock as engine rpm varies.



SYSTEM OR COMPONENT TO CHECK ACTION



COOLING CHECK Over heating problems:
- Low engine coolant level and leaks.
- Water pump operation, loose belts
- Restricted air flow to radiator or
restricted coolant flow.
- Faulty or incorrect thermostat.
- Correct coolant solution - should be a 50/50
mix of anti-freeze (coolant) and water.
- Fan operation.



FUEL NOTE To determine if the condition is caused by
a lean system, the vehicle should be driven at the
speed of the complaint. Monitoring block learn will
help identify the problem (Lean - Block learn greater
than 150).
CHECK FUEL PRESSURE refer to FUEL SYSTEM PRESSURE
TEST/ DIAGNOSIS, TESTING AND INSPECTION
PROCEDURES in FUEL SUPPLY AND AIR INDUCTION.
FUEL QUALITY and proper octane rating: refer to ALCOHOL
IN FUEL TEST/ DIAGNOSIS, TESTING AND INSPECTION
PROCEDURES in FUEL SUPPLY AND AIR INDUCTION.




IGNITION CHECK SPARK PLUGS for proper heat range.
ESC system operation.
TIMING.




EMISSIONS CHECK EGR system and Valve operation.
Refer to EXHAUST GAS RECIRCULATION (EGR)
SYSTEM/ DIAGNOSIS, TESTING AND INSPECTION PROCEDURES
PROCEDURES in EMISSION CONTROL DEVICES.
THERMOSTATIC AIR CLEANER operation.




ENGINE/TRANSMISSION CHECK - Carbon buildup Remove carbon with
top engine cleaner. Follow instructions on can.
- For incorrect basic engine parts such as cam,
heads, pistons, etc.
- For excessive oil entering combustion chamber.
- Proper transmission shift points.
- Torque Converter Clutch (TCC) operation.