Firebird V8-305 5.0L (1982)
Thermal Vacuum Valve: Service and Repair
EFE Distributor Thermal Vacuum Switch (EFE-DTVS)
Early Fuel Evaporation Distributor Thermal Vacuum Switch (EFE-DTVS)
The EFE-DTVS is an engine coolant sensitive vacuum switch which controls vacuum to both the distributor and EFE valve. When engine coolant
temperatures are below the calibration point of the switch, manifold vacuum is directed to the EFE system and the distributor vacuum advance is
vented to atmosphere. When engine coolant temperatures are above the calibration point of the switch, the EFE actuator is vented to atmosphere
while the distributor receives ported vacuum for proper spark advance.
