Fuel Filler Cap: Description and Operation

PURPOSE
The Fuel Filler Cap is designed to keep fuel vapors from the atmosphere by keeping raw fuel vapors in the tank until purged and allowing fresh air to flow into the Fuel Tank.

OPERATION
When the Thermal Vacuum Valve (TVV) opens and allows engine vacuum to draw fuel vapors into the combustion process through the canister, fresh air is drawn into the Fuel Tank through the check valve in the Fuel Cap.