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.