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Fuel Pressure Regulator

The fuel pressure regulator used on the MPFI fuel system is a vacuum assisted, non-adjustable type. The fuel pressure regulator is mounted on the output end of the fuel rail and is connected to intake manifold vacuum. See Fig 1 . The regulator is calibrated to maintain fuel system pressure (at idle) at approximately 31 psi (2.18 kg/cm2 ) with vacuum applied to regulator. Fuel pressure (at idle) is approximately 8-10 psi (.56-.70 kg/cm2 ) higher if vacuum is not applied to the regulator.

Fig 1: Fuel Pressure Regulator, Fuel Rail & Fuel Injectors
G113133Courtesy of CHRYSLER MOTORS.