Fuel Pressure Regulator: Description and Operation

Fuel Pressure Regulator Assembly (Typical):

DESCRIPTION
The fuel pressure regulator is a diaphragm-operated relief valve with fuel pump pressure on one side, and regulator spring pressure and intake manifold vacuum on the other. Its function is to maintain a constant pressure differential across the injectors at all times. The pressure regulator compensates for engine load by increasing fuel pressure as engine vacuum drops.

With the ignition "ON" and engine "OFF" (zero vacuum), fuel pressure should be 284 to 325 kPa (41 to 47 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) 45 may result. Refer to Chart A-6 Fuel System Diagnosis/Computers and Control System/System Diagnosis/Procedures for diagnosis of fuel pressure conditions. Testing and Inspection