Fuel Pressure and Residual Pressure Before High Pressure Pump, Checking

Fuel Pressure and Residual Pressure before High Pressure Pump, Checking

Special tools, testers and auxiliary items required

• Fuel Inj. Pressure Gauge-CIS (V.A.G 1318)

• Adapter (V.A.G 1318/11)

• Adapter (V.A.G 1318/17-1A)

• Fuel Line Feed Adapter (V.A.G 1318/23)

• Measuring container, fuel-resistant

• Protective gloves

Fuel Pressure, Checking

• Battery voltage at least 12.5 Volts.

• Fuel filter OK.

• Fuel tank minimum 1/4 full.

• Fuel Pump (FP) control module (J538) OK

• Ignition switched off

Fuel system is under pressure! Before opening system, place clean rags around the connection. Then release pressure by carefully loosening the connection.

- Fold the boot - 1 - to the side and disconnect the fuel line.

- First push the hose coupling - 2 - downward - arrow A -, then press the release buttons - arrow B -.

- Remove the hose coupling with the release buttons pressed.






- Connect the (V.A.G 1318/23) and (V.A.G 1318/17-1A) to the (V.A.G 1318).






- (V.A.G 1318/17-1A) attach to the fuel line from the fuel tank

- Connect the (V.A.G 1318/11) to the (V.A.G 1318).

- Push an assisting hose - arrow - onto it and hold it into a measuring container.

- Close the shut-off valve on the (V.A.G 1318).






• Lever stands perpendicular to direction of flow - arrow -.

- Connect the vehicle diagnosis tester.

- Select "engine electronics" in OBD.

- Then select "output diagnostic test".

- Select "fuel pump electronics" and press "start".

• This function controls the fuel pump.

- Read the fuel pressure on the (V.A.G 1318).

• Specified value: 5 to 8 bar

- Stop the function when the fuel pressure stops rising on the (V.A.G 1318).

If the specification is not obtained:

- Check the fuel delivery quantity of individual fuel pumps.

Residual Pressure, Checking

- Check for leaks and residual pressure by watching for the pressure on the (V.A.G 1318) to decrease.

• After 10 minutes there must be a residual pressure of at least 3 bar.

If the residual pressure drops below 3 bar:

• Check connection between pressure gauge and fuel line for leaks.

• Check pressure gauge for leaks.

• Check fuel lines and their connections for leaks.

• Replace the fuel filter or fuel pressure regulator.

• Replace fuel pump.

Assembling

Assemble in reverse order of disassembling. Note the following:

- Turn off the ignition.

• Before disconnecting the pressure gauge, release pressure by opening shut-off valve. Hold the hose in a measuring container - arrow -.






- Connect the fuel supply line 1. Check for cleanliness and leaks.

• Check fuel system for leaks.