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: ^ For obvious over heating problems.
^ FAN OPERATION: Check fan clutch operation
^ Low engine coolant level and leaks.
^ WATER PUMP: Operation, loose belts
^ Restricted air flow to radiator or
restricted coolant flow.
^ THERMOSTAT: Faulty or incorrect.
^ Correct coolant solution - should be a 50/50
mix of anti-freeze (coolant) and water.




COMPUTER INPUTS/OUTPUTS CHECK: ^ IGNITION CONTROL UNIT: Improper wiring
or defective control unit
^ CRANKSHAFT POSITION/SPEED SENSOR:
Damaged or improperly installed crankshaft
position/speed sensor.




FUEL
CHECK: ^ LEAN FUEL/AIR MIXTURE: Test fuel pump
pressure and volume output.
^ FUEL INJECTOR:
Fuel injector spray pattern, clogged,
or stuck injector.
^ FUEL QUALITY:
Poor or contaminated fuel, proper octane rating.



IGNITION CHECK: ^ SPARK PLUGS: Proper heat range.
^ IGNITION CONTROL UNIT: Improper wiring
or defective control unit
^ CRANKSHAFT POSITION/SPEED SENSOR:
Damaged or improperly installed
crankshaft position sensor.




ENGINE/TRANSMISSION CHECK: ^ CARBON BUILD-UP: Remove carbon at
intake valves.
^ Incorrect basic engine parts such as cam,
heads, pistons, etc.
^ Excessive oil entering combustion chamber.
^ Proper transmission shift points.