Detonation/Spark Knock. Pontiac Sunfire 2002

For 1990-2009 cars only

Makes 🢒 Pontiac 🢒 2002 🢒 Sunfire 🢒 Engine 🢒 Engine Controls - 2.2L (L61) 🢒 Detonation/Spark Knock

Detonation/Spark Knock

Checks

Action

DEFINITION: The engine makes a mild to severe pinging noise, which is usually worse during acceleration. The engine makes sharp metallic knocks that change with the throttle opening.

Preliminary Checks

•	Refer to Diagnostic System Check - Engine Controls .

•	Refer to Symptoms - Engine Controls .

•	Search the service bulletins.

Fuel System

•	Check for low fuel pressure. Refer to Fuel System Diagnosis .

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

•	Check for conditions that can cause an engine to run lean, where the long-term fuel trim is significantly in the positive range. Refer to Diagnostic Aids for DTC P0171 .

Ignition System

•	Check the spark plugs for proper heat range and reach. Refer to Ignition System Specifications .

•	Check the knock sensor (KS) system for no retard timing.

Engine Cooling System

Check for obvious overheating problems, including the following conditions:

•	Low engine coolant

•	Restricted air flow to the radiator

•	Restricted water flow through the radiator

•	Inoperative electric cooling fan circuits

•	Incorrect thermostat operation

The correct coolant solution should be a 50/50 mix of Dexcool® or an equivalent mixture of antifreeze coolant and water. Refer to Thermostat Diagnosis in Engine Cooling.

Engine Mechanical

•	Excessive oil in the combustion chamber. This condition can be caused by leaking valve seals. Refer to Oil Consumption Diagnosis in Engine Mechanical 2.2 L (L61).

•	High cylinder compression--Refer to Engine Compression Test in Engine Mechanical 2.2 L (L61).

•	Excessive carbon buildup--Check the combustion chambers. Clean the chambers with Top engine cleaner. Follow the instructions on the can.

•	Incorrect basic engine parts. Inspect the following:

-	The camshafts

-	The cylinder head

-	The pistons

-	Other components, as applicable.

Additional Checks

•	Check for proper operation of the manifold absolute pressure (MAP) sensor. Ensure that the MAP sensor is not out of range.

•	Check the park/neutral position (PNP) switch input with the vehicle in drive, and with the gear selector in drive or in overdrive.

•	Check the torque converter clutch (TCC) operation. Applying the TCC too soon can cause the engine to spark knock. Refer to Road Test in Automatic Transmission 4T40-E/4T45-E.

•	If the scan tool readings are normal, and if there are no engine mechanical malfunctions, fill the fuel tank with a known quality gasoline that has a minimum octane reading of 87. Re-evaluate the vehicle performance.