Fuel pressure regulator

Before working on components of the fuel supply system, to prevent dangerous fuel spilling, proceed as follows:

• Disconnect the fuel pump supply relay (1).

• Run the engine until it stops.

FUEL PRESSURE REGULATOR

The task of the fuel pressure regulator is to keep a constant difference between the pressure of the fuel and the pressure in the intake manifold. This way it is possible to meter the quantity of fuel solely on the basis of the injector opening time. The pressure regulator is fitted downstream of the fuel distributor manifold. It is a regulating-limiting device controlled by a diaphragm which adjusts the fuel pressure at 3 bar. When the fuel pressure exceeds the maximum rating, the diaphragm operates a valve which opens the return pipe, through which the excess fuel returns to the tank.

A tube connects the regulator spring chamber with the intake box. Through this connection an interdependence is created between the pressure of the fuel circuit and pressure in the intake box, so that the pressure between the injector inlet and outlet is always the same when they are open.

REMOVING/REFITTING

1. Disconnect the vacuum takeoff pipe from the fuel pressure regulator.
2. Disconnect the excess fuel return pipe from the fuel pressure regulator.
3. Slacken the fastening screws and withdraw the fuel pressure regulator from the fuel distributor manifold and retrieve the O-Ring.

1. Regulator body
2. Fastening screws
3. Return pipe connection