Fuel Pressure Regulator: Description and Operation

Fuel Pressure Regulator:

DESCRIPTION
The fuel pressure regulator (1) is a diaphragm-operated relief valve (6) with fuel pump pressure on one side, and regulator spring (2) pressure and intake manifold vacuum on the other side. The regulator's 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 pressure regulator is mounted on the fuel rail.

The cartridge regulator is serviced as a separate component. When servicing the fuel pressure regulator, insure that the back-up 0-ring (3), large 0-ring (4), filter screen (5), and small 0-ring (7) are properly placed on the pressure regulator.

With the ignition On, and engine Off (zero vacuum), system fuel pressure at the pressure test connection should be 317-407 kPa (46-59 psi). If the pressure regulator supplies fuel pressure which is too low or too high, a driveability condition will result.