Bowl Ventilation System

A switch vent solenoid, operated by the ignition switch and ECM, prevents float chamber fuel vapor from escaping into the atmosphere. When the engine is not running, the solenoid valve closes the float chamber vent tube and vapor flows into a vapor storage canister. When the engine is running, the ECM sends a signal to the solenoid to open the inner vent tube and vapor is drawn into the carburetor and engine.