Impreza Wagon FWD F4-1820cc 1.8L SOHC (1995)
Fuel Pressure Regulator: Description and Operation
PURPOSE/OPERATION
Maintains fuel pressure at 250.1 kPa (36.3 psi) above manifold pressure. Fuel flows from the pump, through the lines, to the injectors and to the
pressure regulator. Fuel pressure acting on the diaphragm opens the return line orifice to the fuel tank. As manifold vacuums lowers (during
acceleration), the spring in the diaphragm closes the passage, increasing fuel pressure.
As manifold vacuum increases, the spring tension is overcome and the orifice is opened, allowing more fuel to return to the tank, lowering fuel
pressure.