Detonation/Spark Knock

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: Overheating Problems.
- Low coolant level and leaks.
- Water pump operation, loose belts.
- Restricted air flow through radiator
- Restricted coolant flow.
- Faulty or incorrect thermostat.
- Incorrect coolant solution - should be a 50/50
mix of anti-freeze (coolant) and water.
- Fan operation (electric or belt driven).



COMPUTER INPUTS/OUTPUTS CHECK: - COOLANT TEMPERATURE SENSOR.
Verify Temperature sensor is working
properly, refer to COMPONENT TESTS.
- KNOCK SENSOR. (if equipped)
Refer to COMPONENT TESTING PROCEDURES.




FUEL CHECK: - FUEL PRESSURE.

- FUEL QUALITY.
Poor or contaminated fuel, proper octane rating.



IGNITION CHECK: - SPARK PLUGS for proper heat range.
- SPARK CONTROL System operation.
- IGNITION TIMING.




EMISSIONS CHECK: - EGR operation.
- THERMOSTATIC AIR CLEANER operation.




ENGINE/TRANSMISSION CHECK: - CARBON BUILD-UP.
Remove carbon with top engine cleaner.
Follow instructions on container.
- Incorrect Engine Parts
(camshaft, cylinder heads, pistons, etc.)
- Excessive Oil Entering Combustion Chamber.
- Transmission Shift Points.
- Torque Converter Clutch (TCC) operation.