GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2007 🢒 Vibe - FWD 🢒 Engine 🢒 Engine Controls and Fuel - 1.8L (LV6) 🢒 Backfire

Backfire

Checks

Action

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

Preliminary Check
    • Refer to Diagnostic System Check - Vehicle .
    • Refer to Symptoms - Engine Controls .

Ignition System Checks
    • Check for the proper ignition coil output voltage with a J 26792 Spark Tester or equivalent.
    • Inspect the spark plugs for correct operation and good ignition system performance. Refer to Spark Plug Inspection .
    • Inspect the ignition coil boots for damage.

Engine Mechanical Checks
    • Check for any of the following engine mechanical problems:
       - Broken or weak valve springs
       - Low compression
       - Sticking or leaking valves
       - Incorrect valve timing
       - Incorrect or worn camshaft
       - Refer to Engine Mechanical.
    • Check the intake and the exhaust system for casting flash or other restrictions.