Fuel Pressure Regulator: Description and Operation

Pressure Regulator:

PURPOSE

The Fuel Pressure Regulator is used to maintain Fuel Rail pressure at a set pressure, that is in relation to intake manifold pressure.

OPERATION

The pressure regulator is mounted to the return line end of the fuel rail, it controls the fuel flow back to the Fuel tank, keeping the pressure of the Fuel Rail in a desired range. When intake manifold vacuum is low (fuel demand high) spring pressure inside the regulator causes the valve to partially close which will increase fuel pressure in the fuel rail. When intake manifold vacuum is high (fuel demand low) vacuum acting on the diaphragm compresses the spring, opening the valve further. Return fuel flow increases resulting in lower fuel pressure in the fuel rail. For testing see Fuel System/ Testing And Inspection


Note: A Pressure Regulator Control Valve (PRCV) is used to aid in hot starting. During hot starting, the PRCV cuts off manifold vacuum to the fuel pressure regulator. This is mounted in line between the Intake Manifold vacuum port and the Fuel Pressure Regulator vacuum port.