Detonation/Spark Knock. Cadillac DeVille 2002

For 1990-2009 cars only

Makes 🢒 Cadillac 🢒 2002 🢒 DeVille 🢒 Engine 🢒 Engine Electrical 🢒 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

•	Refer to Important Preliminary Checks Before Starting in Symptoms - Engine Controls .

•	Search for bulletins.

Fuel System

•	Check the fuel pressure. Refer to Fuel System Diagnosis .

•	Check for items that cause the engine to run lean.

•	Check for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

Ignition System

Check the spark plugs. Refer to Spark Plug Inspection

Engine Cooling System

Check for causes of overheating:

•	Low engine coolant level. Refer to Loss of Coolant in Engine Cooling.

•	Restricted air flow to radiator, or restricted coolant flow through the radiator. Refer to Engine Overheating in Engine Cooling.

•	Insufficient cooling fan operation. Refer to Cooling Fan Inoperative in Engine Cooling.

Engine Mechanical

•	Check for excessive oil in the combustion chamber-leaking valve seals. Refer to Oil Consumption Diagnosis

•	Engine compression. Refer to Engine Compression Test in Engine Mechanical.

•	Check the combustion chamber for excessive carbon buildup. Clean using Top Engine Cleaner.

•	Check for incorrect basic engine parts. Inspect the following:

Camshafts

-	Cylinder heads

-	Pistons, etc.

Additional Checks

•	Check the torque converter clutch system for proper operation. Refer to Torque Converter Diagnosis in Automatic Transaxle.

•	If the scan tool readings are normal, 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.