Anti-Afterburn Valve
Valve is of gulp type design, and is a control device which provides a suitable air/fuel mixture during deceleration, by injecting additional fresh air into intake manifold to prevent mixture from becoming too rich to burn in engine. This unburned mixture, when discharged into exhaust manifold, could cause a backfire when mixed with air from air injection system. Valve is controlled by intake manifold vacuum so that when vacuum is high (during deceleration or shifting), valve opens allowing air pump output to be diverted into intake manifold.