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For 1990-2009 cars only
Makes 🢒 Oldsmobile 🢒 1999 🢒 Intrigue 🢒 Engine 🢒 Engine Controls - 3.8L 🢒 Detonation/Spark Knock

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 Checks
    • Refer to Important Preliminary Checks Before Starting.
    • Refer to Visual/Physical Checks
    • Search for bulletins.

Fuel System
    • Test for low fuel pressure. Refer to Fuel System Pressure Test .
    • Test for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Test the items that can cause an engine to run lean Refer to DTC P0171 Fuel Trim System Lean .

Ignition System

Inspect the spark plugs for proper heat range and reach.

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. Refer to Electric Cooling Fan Diagnosis .
    • The correct coolant solution should be a 50/50 mix of GM P/N 1052753, or equivalent, antifreeze coolant and water.

Engine Mechanical
    • Test for excessive oil in the combustion chambers or leaking valve seals. Refer to Cylinder Leakage Test .
    • Test for low cylinder compression. Refer to Engine Compression Test .
    • Inspect the combustion chambers for excessive carbon buildup. Clean the cylinders using Top engine cleaner. Follow the instructions on the can.
    • Inspect for incorrect basic engine parts. Inspect the following:
       - The camshaft
       - The cylinder heads
       - The pistons, etc.

Additional Checks
    • Test for proper EGR system operation. Refer to DTC P0401 Exhaust Gas Recirculation (EGR) Flow Insufficient .
    • Test for proper operation of the knock sensor circuits. Refer to DTC DTC P0327 Knock Sensor Circuit Low Voltage and DTC P0332 Knock Sensor (KS) 2 Circuit .
    • Test the transaxle range switch input with the vehicle in drive and the gear selector in drive or overdrive.
    • Test the TCC operation. The TCC applying too soon can cause the engine to spark knock.
    • If the scan tool readings are normal and there are no engine mechanical faults, fill the fuel tank with a known quality gasoline that has a minimum octane reading of 87 and re-evaluate the vehicle performance.