GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2000 🢒 Sunfire 🢒 Engine 🢒 Engine Controls - 2.2L 🢒 Backfire

Backfire

Checks

Actions

DEFINITION: Fuel ignites in the intake manifold, or in the exhaust system, making a loud popping noise.

Preliminary Checks
    • Refer to Symptoms .
    • Search for 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 .
    • Ensure that each injector harness is connected to the correct injector/cylinder. Refer to Engine Controls Schematics .
        .

Ignition System
    • Check for proper ignition voltage output with the J 26792 spark tester or equivalent.
    • Check the spark plugs for the following conditions:
       - Wet or fuel fouled spark plugs
       - Cracks on the spark plugs
       - Wear.
       - Improper spark plug gap
       - Burned electrodes or heavy deposits
    • If the spark plugs are fuel or oil-fouled, determine the cause of the fouling before replacing the spark plugs.
    • Check the ignition control module (ICM) for proper ground connection.
    • Check the ignition coils for cracks or carbon tracking.
    • Check the spark plug wires for proper resistance and condition.

Engine Mechanical
    • Check engine mechanical:
       - Check compression
       - Sticking or leaking valves
       - Worn camshaft lobes
       - Valve timing
       - Bent push rods
       - Worn rocker arms
       - Broken valve springs
       - Excessive oil in combustion chamber-Leaking valve seals
       - Low cylinder compression
    • For incorrect basic engine parts. Inspect the following:
       - The camshaft
       - The cylinder heads
       - The pistons
       - Other engine parts, as appropriate
    • Refer to Base Engine Misfire Diagnosis in Engine Mechanical.

Additional Checks
    • Check the intake and exhaust manifolds for casting flash. Refer to Intake Manifold Cleaning and Inspection in Engine Mechanical.
    • Check the exhaust system for possible restriction. Check the following:
       - The exhaust system for damaged or collapsed pipes.
       - The mufflers for heat distress or for possible internal failure.
       - A possible plugged three-way catalytic converter. Refer to Restricted Exhaust and Exhaust System.