GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2002 🢒 Safari - 4WD 🢒 Engine 🢒 Engine Electrical 🢒 Backfire

Inspections

Action

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

Preliminary

Refer to Symptoms - Engine Controls .

Ignition System

Inspect the ignition system. Refer to Distributor Ignition (DI) System Diagnosis .

Engine Mechanical
    • Inspect the engine for the following the items:
       - Engine compression--Refer to Engine Compression Test in Engine Mechanical.
       - Improper valve timing
       - Manifold gaskets
       - Sticking or leaking valves--Refer to Valve Lifters and Guides Cleaning and Inspection in Unit Repair.
    • Inspect the intake and exhaust system for fresh air entering the exhaust upstream of the catalytic converter or restrictions. Refer to Intake Manifold Cleaning and Inspection or Exhaust Manifold Cleaning and Inspection in Unit Repair.

Fuel System
    • Inspect the fuel system performance. Refer to Fuel System Diagnosis .
    • Perform the fuel injector balance test. Refer to Fuel Injector Balance Test with Tech 2 .