Fuel Pressure Regulator: Description and Operation

Fuel Pressure Regulator Assembly

The fuel pressure regulator is a part of the fuel sender assembly fuel return pipe. The fuel pressure regulator is a diaphragm operated relief valve. A software bias compensates the injector on-time because the fuel pressure regulator is not referenced to manifold vacuum. The fuel injector pulse width varies with the signal from the MAP sensor. With the ignition ON and the engine OFF, system fuel pressure at the pressure test connection should be 380-410 kPa (55-60 psi). If the pressure is too low, poor performance could result. If the pressure is too high, excessive odor and a Diagnostic Trouble Code (DTC) P0132, P0152, P0172 or P0175 may result. Refer to Fuel System Diagnosis for information on diagnosing fuel pressure conditions Component Tests and General Diagnostics.