Impreza Coupe FWD F4-1820cc 1.8L SOHC (1995)
Air Suction Valve: Description and Operation
PURPOSE/OPERATION
Allows fresh air to enter the exhaust manifold. The ECM operates the solenoid, allowing vacuum applied to the diaphragm to open the main
passage of the ASV. Exhaust pressure in the manifold pulsates in response to the opening and closing of the exhaust valves and decreases
periodically below atmospheric pressure creating a vacuum effect. During the periods of negative manifold pressure, the internal valve opens
allowing air to be drawn into the exhaust manifold through the main passage.
