2500 4x2 Pickup V8-5.9L VIN Z (1994)
Fuel Pressure Regulator: Description and Operation
Filter/Regulator - Side View
OPERATION
The pressure regulator is a mechanical device that is not controlled by the Powertrain Control Module (PCM) or engine vacuum.
The regulator is calibrated to maintain fuel system operating pressure of approximately 241-310 kPa (35-45 psi) at the fuel injectors. It contains a
diaphragm, calibrated springs and a fuel return valve. The internal fuel filter is also part of the assembly.
Fuel is supplied to the filter/regulator by the electric fuel pump through an opening tube at the bottom of filter/regulator.
The filter/regulator contains a check valve to maintain some fuel pressure when the engine is not operating. This will help to start the engine.
If fuel pressure at the pressure regulator exceeds approximately 45 psi, an internal diaphragm closes and excess fuel pressure is routed back into
the tank through the pressure regulator. A separate fuel return line is not used with this system.
