Checking fuel pressure regulator and residual pressure

The fuel pressure regulator maintains the fuel pressure at a constant 4.0 bar.

Test condition

Performance fuel pumps should be the norm.

Checking procedure

Remove the adapter VAG 1318/201 adapter VAG 1318/20.

Turn the valve on the T-shaped portion of the adapter VAG 1318/20 counterclockwise and open it completely (Fig. 2.281).

Remove the protective cover of the air valve.

Now connect to the air valve 1 pressure gauge VAG 1318 as shown in Figure 2.282, the adapter VAG 1318/20, VAG 1318/201, VAG 1318/9 and evacuating device VAS 5226.

Crane gauge - hand - should be closed.

Start the engine and leave it idling.

Screw the valve on the T-shaped portion of the adapter VAG 1318/20 clockwise until it stops at the air valve.

Very open and close the valve pressure gauge to vent the air from the hose to the pressure gauge (Fig. 2.283).

Measure the fuel pressure. Specification: about 4.0 bar.

If the setpoint pressure is not achieved, check the performance of the fuel pump.

If necessary, replace the fuel pressure regulator.

If the nominal value is reached, turn off the ignition.

Now check the tightness and residual pressure. To do this, make sure of the pressure drop on the pressure gauge. After 10 min, the pressure should be maintained at least 3.0 bar.

If the residual pressure drops below 3 bar gauge, check for leaks.

Check the fuel pump check valves.

If you turn off the pressure gauge after the test switch off the ignition.

Open the valve on the pressure gauge to reset the fuel pressure.

Remove the pressure gauge with the adapters.

Under the joint further enclose rags to soak up leaking fuel.