Anti-Backfire Valve

The anti-backfire valve is used to prevent backfire in exhaust system during deceleration. At start of deceleration, air/fuel mixture in intake manifold becomes too rich to ignite and burn in combustion chamber.

The anti-backfire valve provides additional air to intake manifold to make air/fuel mixture leaner and prevent backfire. If valve is faulty, unburned air/fuel mixture will be emitted to exhaust manifold and ignite when mixed with secondary air, causing backfire.