Justy Wagon 4WD L3-1.2L SOHC (MPFI) (1992)
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Fuel Pressure Regulator: Description and Operation
Fuel Pressure Regulator
PURPOSE
Maintains fuel pressure at 31.3 psi (216 kpa) above manifold pressure.
LOCATION
On the L.H. side of injector rail (has a vacuum fitting).
OPERATION
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 orfice to the fuel tank. As manifold vacuums lowers (during accel), the spring in the diaphragm closes the passage, increasing fuel pressure.
As manifold vacuum increases, the spring tension is overcome and the orfice is opened, allowing more fuel to return to the tank, lowering fuel
pressure.