Fuel Pressure Regulator: Description and Operation

PURPOSE
The Fuel Pressure Regulator controls the fuel pressure to the inlets of the fuel injectors. The Regulator has an operational range of 28 - 44 psi and is controlled by engine manifold vacuum.

OPERATION
The Fuel Pressure Regulator contains a diaphragm and spring that opens and closes a check ball opening to the fuel return passage. As vacuum increases, pulling the diaphragm against spring tension, more fuel is relieved to the tank and system fuel pressure decreases. As throttle approaches wide open, manifold vacuum decreases toward zero in. Hg. and the Regulator blocks off more of the fuel return circuit, thus raising the system fuel pressure. This enables the engine to receive additional fuel volume as required by high speed/load driving conditions.