Glossary “backfire” Definition:
1). An explosion in the exhaust system. caused when an unburned air/fuel mixture is ignited, usually upon deceleration. 2). An explosion of the air/fuel mixture in the intake manifold, which is evident at the carburetor or throttle body and may be caused by improper ignition timing, crossed spark plug wires, or an intake valve that is stuck open. 3. The momentary recession of the flame into the welding tip, or cutting tip, followed by immediate reappearance or complete extinction of the flame.