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For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2001 🢒 Sunfire 🢒 Engine 🢒 Engine Electrical 🢒 Detonation/Spark Knock

Detonation/Spark Knock

Checks

Action

DEFINITION: A mild to severe ping, usually worse during acceleration. The engine makes sharp metallic knocks that change with the throttle opening.

Preliminary Checks
    • Refer to Symptoms - Engine Controls .
    • Search for service bulletins.

Fuel System
    • Inspect for low fuel pressure. Refer to Fuel System Diagnosis .
    • Inspect for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Inspect for items that can cause an engine to run lean. Where long term fuel trim significantly in the positive range. Refer to Diagnostic Aids for DTC P0171 .

Ignition System
    • Inspect the spark plugs for proper heat range and reach. Refer to Ignition System Specifications .
    • Inspect the knock sensor (KS) system for no retard timing.

Engine Cooling System

Inspect for obvious overheating problems:

    • Low engine coolant
    • Restricted air flow to the radiator, or restricted water flow through the radiator
    • Inoperative electric cooling fan circuits
    • Correct coolant solution should be a 50/50 mix of DEX-COOL® or an equivalent antifreeze coolant and water. Refer to Engine Overheating in Engine Cooling.

Engine Mechanical
    • Excessive oil in the combustion chamber-Leaking valve seals. Refer to Oil Consumption Diagnosis in Engine Mechanical 2.2L.
    • Low cylinder compression--Refer to Engine Compression Test in Engine Mechanical 2.2L.
    • Inspect the combustion chambers for excessive carbon buildup. Clean the chambers using a good-quality engine cleaner. Follow the instructions on the container.
    • For incorrect basic engine parts. Inspect the following:
       - The camshaft
       - The cylinder heads
       - The pistons
       - Other engine parts, as appropriate
    • Refer to Diagnostic Starting Point - Engine Mechanical in Engine Mechanical 2.2L.

Additional Checks
    • Inspect the transaxle range switch input with the vehicle in Drive and with the gear selector in Drive or Overdrive.
    • Inspect the torque converter clutch (TCC) operation. Applying the TCC too soon can cause the engine to spark knock. Refer to Torque Converter Diagnosis in Automatic Transaxle 3T40.
    • 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 rating of 87 and re-evaluate the vehicle performance.