Fuel Pressure Regulator: Operation
Fuel Pressure Regulator Operation: The pressure regulator 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. See Fig 1.
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.