Fuel Pressure Regulator

Fuel Pressure Regulator:

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 side. The function of the regulator is to maintain a constant 300 kPa fuel pressure across the director spray plate under all operating conditions. The pressure regulator compensates for engine load by increasing fuel pressure as engine intake manifold 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 O-ring, large O-ring, filter screen, and small O-ring are properly placed on the pressure regulator.

With the ignition On, and engine Oft (zero vacuum), system fuel pressure at the pressure test connection should be 284-325 kPa (41-47 psi). If the pressure regulator supplies fuel pressure which is too low or too high, a driveability condition will result.

The fuel injector is a solenoid device controlled by the PCM that meters pressurized fuel to a single cylinder. When the PCM energizes the injector coil, a normally closed ball valve opens, allowing fuel to flow past a director plate to the injector outlet. The director plate has holes that control the fuel flow, generating a dual conical spray pattern of finely atomized fuel at the injector outlet. Fuel from the outlet is directed at both intake valves, causing it to become further vaporized before entering the combustion chamber.

Fuel injectors will cause various driveability conditions if they will not open, are stuck open, leaking or have a low coil resistance.