The Evaporative Emission (EVAP) control system limits the fuel vapor escape into the atmosphere. The system transfers the fuel vapor from a sealed fuel tank [5 and 3 (auxiliary fuel tank if equipped)], through a single vapor pipe (6) in order to an activated carbon (charcoal) storage device (evaporative emission canister 8) which stores the vapors when the vehicle is not operating. When the engine is running, the intake (7) air flow purges the fuel vapor from the carbon element before sending the vapor to the TBI unit (2) through the purge hose (1). The normal combustion process consumes the vapors. The Control Vacuum Hose (9) provides a manifold vacuum for the EVAP control system.

The fuel tank has a valve (4) which allows both a pressure and a vacuum relief.

The system purges the fuel vapors from the fuel tank. The vapors flow into the canister tube labeled fuel tank (5), and the carbon (6) absorbs the vapors. The system purges (purge valve 3) the canister when the engine runs above the idle speed. The system applies a timed vacuum source to the EVAP canister tube labeled canister purge (1) in order to draw the fresh air through the air inlet at the top of the canister. This air flows through a tube (4) to the bottom of the canister and forces the vapors out the purge line(2).