Fuel Pressure Regulator

The pressure regulator is a mechanical device that is calibrated to maintain fuel system operating pressure of approximately 379 kPa (55 psi) at fuel injectors. It contains a diaphragm, calibrated springs and a fuel return valve. Fuel is supplied to regulator by electric fuel pump through an opening tube at bottom of regulator.

The fuel pump module contains a check valve to maintain some fuel pressure when engine is not operating. This will help to start engine. If fuel pressure at pressure regulator exceeds approximately 56 psi, an internal diaphragm closes and excess fuel pressure is routed back into tank through pressure regulator. A separate fuel return line is not used with any gas powered engine. The pressure regulator is a mechanical device that is NOT controlled by PCM or engine vacuum.