Monte Carlo V6-262 4.3L VIN Z TBI (1985)
Thermal Vacuum Valve: Description and Operation
Early Fuel Evap. Dist. Thrml. Vac. Sw. (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.
