Backfire. Chevrolet Express 2000

For 1990-2009 cars only

Makes 🢒 Chevrolet 🢒 2000 🢒 Express 🢒 Engine 🢒 Engine Controls - 7.4L 🢒 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 .

Ignition System Checks

•	Check the ignition system. Refer to Enhanced Ignition System Diagnosis .

•	Check for crossfire between spark plugs, such as the distributor cap, spark plug wires, and proper routing of the plug wires.

Engine Mechanical Checks

•	Check the engine for the following the items:

-	Engine compression

-	Improper valve timing

-	Manifold gaskets

-	Sticking or leaking valves

•	Check the exhaust gas recirculation (EGR) operation for being open all of the time. Refer to Exhaust Gas Recirculation (EGR) System Diagnosis .

•	Check the intake and exhaust system for fresh air entering the exhaust upstream of the catalytic converter or restrictions.

Fuel System Checks

•	Check the fuel system performance. Refer to Fuel System Diagnosis .

•	Perform the fuel injector balance test. Refer to Fuel Injector Balance Test with Tech 2 .

Additional Checks

•	Check the EGR gasket for a damaged gasket or loose fit.

•	Check the AIR system for proper operation, if applicable.