4 Runner 4WD V6-180.5 2959cc 3.0L SOHC (3VZ-E) (1989)
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Fuel Pressure Vacuum Switching Valve: Description and Operation
Fuel Pressure Up System Schematic
PURPOSE
The fuel pressure-up vacuum switching valve (VSV) controls the vacuum to the fuel pressure regulator.
LOCATION
Located on the RH side of the engine.
OPERATION
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.
