Tercel Sedan 2-Door L4-1456cc 1.5L SOHC (3E-E) (1991)
Fuel Pressure Vacuum Switching Valve: Description and Operation
Fuel Pressure-Up VSV Circuit Schematic
The Fuel Pressure-up Vacuum Switching Valve (VSV), located on the RH side of the engine compartment, controls the vacuum to the Fuel Pressure
Regulator (FPR). When the ECU senses high coolant temperature, it grounds the VSV via terminal FPU and interrupts manifold vacuum to the FPR.
This initiates a 6 - 7 psi increase in fuel pressure at the injectors. The lean fuel condition, caused by high engine temperature, is enriched by the
increased fuel pressure.