A method for operating an evaporative emissions control system for use with a fuel tank that stores and delivers fuel to an internal combustion engine is provided. A vent shut-off assembly is provided that selectively opens and closes at least one valve to provide overpressure and vacuum relief for the fuel tank. The vent shut-off assembly selectively vents to a purge canister. The at least one valve is closed whereby vapor is precluded from passing from the fuel tank to the purge canister. A purge event is performed wherein dedicated fresh air is drawn into the purge canister and delivered from the purge canister to the engine.