Backfires

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

POSSIBLE CAUSE ACTION


EGR open all the time, 1. Check EGR system under
leaking gasket TESTING PROCEDURES.
2. Check EGR electronic controls.
Refer to COMPUTERIZED ENGINE CONTROLS.



Air management valves, Check Air Injection system under
Deceleration valve, TESTING PROCEDURES.
Check valves malfunctioning