Detonation/Spark Knock/Pings

DEFINITION
A mild to severe knock, that usually occurs under acceleration. The engine produces sharp metallic sounds that change with throttle opening. Generally higher pitched than an engine knock. May be described as a ticking or clatter noise. Occurs when fuel/air charge is ignited by something other than the spark plug.

POWERTRAIN SYSTEM CHECK
Perform Chart 1 Powertrain System Check. Chart 1 Powertrain System Check

EXHAUST GAS RECIRCULATION (EGR) SYSTEM CHECK
Perform Chart 6EC-2 EGR System Check. Chart 6EC-2 EGR System Check

FUEL SYSTEM CHECK
Perform Chart 6C-1 Fuel System Check. Chart 6C-1 Fuel System Check

Check especially for:

^ Fuel Quality
- low octane level
- contaminants
^ Low fuel pressure
^ Low flow rate injector

IGNITION SYSTEM CHECKS
Perform Chart C-1 Ignition Control Performance Test. C Charts

Check especially for:

^ Correct ignition timing
^ Correct spark plug type and heat range

COOLING SYSTEM
Refer to Cooling System, looking in particular for:

^ Overheating engine
^ Depressurized engine cooling system
^ Restricted engine coolant flow
^ Engine coolant fans inoperative


MECHANICAL CAUSES
Check for:

^ Throttle body deposits
^ Excessive oil consumption
^ Intake valve deposits
^ Engine knock