Fuel Pressure Regulator: Description and Operation

Fig. 13 Fuel Pressure Regulator:

Because of the electronic controls in this injection system, the control pressure (warm up) regulator and pressure relief valve (used in the CIS-Lambda system) are no longer needed. Taking their place is a diaphragm type pressure regulator, Fig. 13, that maintains system pressure at approximately 5.4 bar (78 psi), and control pressure at 0.2 bar (3 psi) below system pressure. The pressure regulator also acts as a one way check valve to maintain pressure in the system once the engine has been shut off.