Fuel Pressure Regulator: Operation
WARNING: This page is about a different car, the 2005 Dodge Stratus and 2005 Chrysler Sebring. However, it is still accessible from the selected car via links, so may be relevant.
Fuel Pressure Regulator Operation: The pressure regulator (Figure) is a mechanical device that is calibrated to maintain fuel system operating pressure of approximately 400 kPa +/-34 kPa (58 psi +/-5 psi.) at the fuel injectors.
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 58 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 gas powered engine.