Backfire. Chevrolet Chevrolet C-Series Medium Duty Truck B7 1998

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 1998 🢒 Chevrolet C-Series Medium Duty Truck B7 🢒 Engine 🢒 Engine Controls - 6.0L and 7.0L 🢒 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 Symptoms for the Important Preliminary Checks.

Ignition System Checks

•	Check for the proper ignition coil output voltage with the spark tester J 26792 or the equivalent.

•	Check the spark plugs. Remove the spark plugs and check for the following items:

Wet plugs

Cracks

Wear

-	Improper gap

-	Burned electrodes

-	Heavy deposits

•	Check the ignition system and the ignition timing. Refer to Distributor Ignition (DI) System Diagnosis .

•	Check for crossfire between spark plugs (distributor cap, spark plug wires, and proper routing of plug wires). Refer to Engine Electrical.

Engine Mechanical Checks

•	Check the engine for the following items:

-	Compression

-	Valve timing

-	Manifold gaskets

-	Sticking or leaking valves

-	Refer to Engine Mechanical

•	Check the intake and exhaust system for casting flash or other restrictions. Refer to Engine Mechanical and Engine Exhaust.

Additional Check

Check the EGR Valve for being open all the time. Refer to Exhaust Gas Recirculation (EGR) System Diagnosis .