Fuel Pressure Regulator: Description and Operation

The cartridge type fuel pressure regulator (1) is a diaphragm-operated relief valve (6) with fuel pump pressure on one side, and pressure regulator spring (2), and intake manifold vacuum on the other side. The regulators function is to maintain a constant fuel pressure across the injectors at all times. The pressure regulator compensates for engine load by increasing fuel pressure as engine vacuum drops.

The cartridge regulator is serviced as a separate component. When servicing the fuel pressure regulator, insure that the O-ring backup (3), large O-ring (4), filter screen (5), and small O-ring (7), are properly placed on the pressure regulator.

If the fuel pressure is too low, poor performance and a DTC PO171, could result. If the pressure is too high, excessive odor and a DTC P0172, may result.