Detonation/Spark Knock. Oldsmobile Aurora 2003

For 1990-2009 cars only

Makes 🢒 Oldsmobile 🢒 2003 🢒 Aurora 🢒 Engine 🢒 Engine Mechanical - 4.0L 🢒 Detonation/Spark Knock

Inspection/Test

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 Inspections Before Starting in Symptoms - Engine Controls .

•	Search for bulletins.

Fuel System

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

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

Inspect the following that may cause the engine to run lean:

Notice: Refer to Heated Oxygen and Oxygen Sensor Notice in the Preface section.

•	Any water intrusion into the HO2S connector.

•	An exhaust leak between the HO2S and the engine--Refer to Exhaust Leakage in Engine Exhaust.

•	Any vacuum leaks.

•	Incorrect fuel pressure--Refer to Fuel System Diagnosis .

•	Any lean fuel injectors--Refer to Fuel Injector Balance Test with Tech 2 and Fuel Injector Balance Test with Special Tool .

•	An inaccurate mass air flow (MAF) sensor-- Refer to Scan Tool Data List .

•	Fuel Contamination--Refer to Alcohol/Contaminants-in-Fuel Diagnosis .

•	Vacuum hoses for splits, kinks and proper connections.

Ignition System

Inspect the spark plugs. Refer to Spark Plug Inspection .

Engine Cooling System

Inspect 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

•	Inspect for excessive oil in the combustion chamber-leaking valve seals. Refer to Oil Consumption Diagnosis in Engine Mechanical 4.0L.

•	Engine compression--Refer to Engine Compression Test in Engine Mechanical 4.0L.

•	Inspect the combustion chamber for excessive carbon buildup. Clean using Top Engine Cleaner. Follow instructions on can.

•	Inspect the following for incorrect basic engine parts:

Camshafts

-	Cylinder heads

-	Pistons, etc.

Additional

•	Inspect the torque converter clutch (TCC) 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.