Fuel Pressure Regulator: Description and Operation

Fuel Pressure Regulator (Cut-Away View):

PURPOSE
Maintains a constant pressure differential between intake manifold absolute pressure and fuel system pressure. In conjunction with Pressure Regulator Control (PRC) Solenoid Valve, prevents vapor lock during hot restart by raising fuel pressure.

LOCATION
Left end of front fuel rail.

OPERATION
Control vacuum is applied to a diaphragm which operates a pressure valve. When the engine is under very light load, control vacuum is high, spring pressure against the regulator valve is reduced and the fuel system is regulated at a lower pressure. When the engine is under heavy load (as in wide open throttle operation), manifold absolute pressure increases reducing control vacuum. More spring pressure is applied to the valve and fuel system pressure is increased by the same amount as manifold absolute pressure, maintaining a constant differential under changing engine loads.