Suburban 3/4 Ton 4WD V8-305 5.0L (1986)
Early Fuel Evaporation ( EFE ): Description and Operation
Vacuum Servo EFE System
Fig. 41 Vacuum servo EFE valve. W/integral actuator
Fig. 42 Vacuum servo EFE valve. W/remote actuator
This system uses a vacuum servo operated heat riser valve, Figs. 41 and 42, to increase flow of exhaust gasses through the intake manifold passage
during cold engine operation. Control signals to the vacuum servo are controlled by a thermo vacuum switch (EFE-TVS) on all except some models
equipped with the C-3 fuel control system. On these models, vacuum signals are controlled by the C-3 system computer through a solenoid operated
vacuum valve (EFE-SOL).
