Fuel Evaporation System: Operation

As fuel expands in tank, fuel laden vapor is forced out of tank through an upper vent port. Vapor flows up from fuel tank vent lines into a left and a right expansion tank.

Fuel vapor then flows from gravity vent valves, through a control valve, and into the charcoal canister where it is adsorbed until manifold vacuum pulls it out of canister for burning.

When the engine is running above idle, a vacuum signal opens control valve and canister vapor is drawn from canister through control valve and into intake manifold for burning.