Fuel Supply Line: Service and Repair

High Pressure Line, Installing

Special tools, testers and auxiliary items required

• Torque Wrench (5-50 Nm) (V.A.G 1331)

• Socket (T40055)


Loosen the fuel rail bolts and move it slightly. This makes it possible to mount the fuel injector lines free of tension. The lines must not be bent or under stress. Long term this would cause the line to break.

• The following describes installing new fuel injector lines. If reinstalling old fuel injector lines, then be sure to check the points listed under - item 5 - in the => [ Fuel Rail and Injectors Overview ] Service and Repair. The procedure is otherwise identical.

Installing the individual fuel injector lines (cylinders 1 through 4 between the rail and the injector)

Tightening specifications, refer to => [ Fuel Rail and Injectors Overview ] Service and Repair.

- Remove the new fuel injector line from its packaging, remove the plug and install the line between the rail and the injector immediately.

- Hand tighten the union nuts for the fuel injector line without using any tools. Make sure the line is seated correctly.

- Proceed the same way with the other fuel injector lines.

- Tighten the rail bolts to specification, if necessary.

- Tighten the union nuts to specification using the torque wrench (5-50 Nm) (V.A.G 1331) and the socket (T40055).






Installing the fuel line (between the high pressure pump and the rail) or the entire wiring harness

Tightening specifications, Refer to => [ Fuel Rail and Injectors Overview ] Service and Repair.

- Loosen the bolts for the rail and make sure the it is possible to move the rail, if this was not done before.

- Take the fuel line between the high pressure pump and the rail out of the packaging, remove the cap and install it immediately.

- Hand tighten the union nuts for the fuel injector line without using any tools. Make sure the line is seated correctly.

- Proceed in the same way with the other four fuel injector lines, if the entire wiring harness has to be installed.

- Install all three clamps over the fuel line. Make sure they are aligned.






- Install the clamp screws approximately 3 thread turns.

- Tighten the fuel rail bolts.

- Tighten the top clamp to the intake manifold to 8 Nm.

- Tighten the union nuts to specification using the torque wrench (5-50 Nm) (V.A.G 1331) and the socket (T40055).






- Tighten the other two clamps to 8 Nm.

- Press the return line connections carefully over the sealing ring onto the injector (check the sealing ring first for damage). The connection must engage audibly. Then press the release pin down carefully.

- Fill the fuel system. Refer to => [ Fuel System, Filling and Bleeding ] Fuel System, Filling and Bleeding.