GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2001 🢒 Firebird 🢒 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 Checks
    • Refer to the Symptoms - Engine Controls .
    • Search for bulletins.

Fuel System
    • Test for incorrect fuel pressure.
    • Test for contaminated fuel. Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
    • Test items that can cause an engine to run lean, with the long-term FT significantly in the positive range. Refer to Diagnostic Aids for DTC P0171 or P0174 .

Ignition System
    • Inspect the spark plugs for proper application.
    • Refer to Ignition System Specifications .

Engine Cooling System

Inspect for obvious overheating conditions:

    • Low engine coolant
    • Restricted air flow to radiator, or restricted water flow through radiator
    • Electric cooling fans malfunction--Refer to Diagnostic System Check - Engine Cooling in Engine Cooling.
    • Correct coolant solution should be a 50/50 mix of GM approved antifreeze coolant and water.

Engine Mechanical
    • Inspect for the following conditions:
       - Excessive oil in combustion chamber-Inspect for leaking valve seals
       - Low cylinder compression
       - Combustion chambers for excessive carbon buildup--Follow instructions on can of engine cleaner in order to clean chambers.
    • For incorrect engine parts, such as the following basic parts:
       - Camshaft
       - Cylinder heads
       - Pistons
    • Refer to Base Engine Misfire without Internal Engine Noises in Engine Mechanical.

Additional Tests
    • Test for proper exhaust gas recirculation (EGR) system operation. Refer to DTC P0401 .
    • Test the transaxle range switch input with the vehicle in drive and the gear selector in drive or overdrive.
    • Test TCC operation. A malfunctioning torque converter clutch (TCC) can cause the engine to spark knock. Refer to Diagnostic Starting Point - Automatic Transmission in Automatic Transmission-4L60-E.
    • If scan tool readings are normal and there are not any engine mechanical conditions, fill the fuel tank with a known quality gasoline that has a minimum octane reading of 87, and re-evaluate vehicle performance.