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.
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Preliminary Checks
|
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Fuel
System
|
• | Check the fuel pressure. |
• | Check items that can cause an engine to run lean. Refer to
DTC P0171
. |
|
Ignition
System
| Check
the spark plugs for proper heat range. Refer to
Maintenance Items
.
|
Engine Cooling System
| Check for obvious overheating problems:
• | Check for low engine coolant. |
• | Check for a restricted air flow to the radiator or restricted
water flow through the radiator. |
• | Inspect for the correct coolant solution. A 50/50 mixture of ethylene
glycol (Dexcool®) should be used. Refer to
Engine Overheating
. |
|
Engine
Mechanical
|
• | Check the combustion chambers for excessive carbon buildup. Use
a top engine cleaner in order to clean the engine parts. Follow the instructions
on the can. |
• | Refer to the appropriate misfire procedures in Engine Mechanical.
Inspect the following components for correct engine parts: |
|
Additional
Checks
|
• | Check for proper exhaust gas recirculation (EGR) system operation.
Refer to
DTC P0401
. |
• | If scan tool readings are normal and there are no engine mechanical
problems, fill the fuel tank with a known quality gasoline that has a minimum
octane rating of 87 and re-evaluate the vehicle performance. |
|