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. The fuel pressure regulator is serviced as a complete assembly.

With the ignition ON and engine off (zero vacuum), the fuel pressure should be between 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 DTC P0172 may result. The Fuel System Pressure Test has information on diagnosing fuel pressure conditions. Refer to Computers and Controls / System Diagnostic Tables / Fuel System Pressure Test.