Skylark V6-173 2.8L VIN X 2-bbl (1984)
Vacuum Check Valve: Description and Operation
Early Fuel Evaporation Delay Valve (EFE-DV)
When vacuum at the EGR-EFE-EMR-DTVS port is greater than the vacuum at the EFE valve actuator port, the check valve closes and vacuum from
the TVS is metered through the restriction to the EFE valve actuator port within 28-42 seconds. When vacuum at the TVS is less than the vacuum at the
EFE port, vacuum from the EFE port flows through the unseated check valve to the TVS port.
