Dakota 2WD V6-239 3.9L Magnum (1996)
Fuel Pressure Regulator: Description and Operation
Fig. 3 Side View - Filter/Regulator
DESCRIPTION
The pressure regulator is a mechanical device that is not controlled by engine vacuum or the powertrain control module (PCM).
OPERATION
The regulator is calibrated to maintain fuel system operating pressure of approximately 339 kPa +/- 34 kPa (49.2 psi +/- 5 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 fuel pump module 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 49.2 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 any engine.