Detonation/Spark Knock
Checks
| Action
|
DEFINITION: A mild
to severe ping, usually worse under acceleration. The engine makes sharp metallic
knocks that change with throttle opening.
|
Preliminary Checks
|
| • | Refer to
Symptoms
, Important
Preliminary Checks Before Starting. |
| • | Verify that the PCM grounds are clean, tight, and in the correct
locations. |
| • | If the scan tool readings are normal (refer to supporting text
of the Powertrain On-Board Diagnostic (OBD) System Check) and there
are no engine mechanical faults, fill the fuel tank with a premium gasoline
that has a minimum octane reading of 92 and re-evaluate the vehicle's
performance. |
|
Fuel System
|
| • | Check for a restricted fuel filter. |
| • | Check the items that can cause an engine to run rich. |
| • | Check items that can cause an engine to run lean. |
|
Ignition System
| Check the spark plugs for the correct heat range.
|
Engine Cooling System
| Check for obvious overheating problems:
| • | A low engine coolant level |
| • | A restricted air flow to the radiator, or restricted water flow
through the radiator |
|
Engine Mechanical
| Check for the following conditions:
| • | Any excessive oil in the combustion chambers may indicate leaking
valve seals. Refer to
Oil Consumption Diagnosis
in Engine Mechanical. |
| • | Any excessive carbon buildup in the combustion chambers. Clean
the chambers using Top Engine cleaner. Follow the instructions on the container. |
| • | Any incorrect basic engine parts. Inspect the following: |
Refer to
Base Engine Misfire Diagnosis
in Engine Mechanical.
|
Additional Checks
|
| • | Check for the correct transaxle range switch operation. |
|
