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)
Removing
• Follow the guidelines for a clean working environment when working on the fuel system, refer to => [ Clean Working Conditions ] Clean Working Conditions.
• Always follow these rules before and during work.
- Remove the engine cover. Refer to => [ Engine Cover ] Engine Cover.
• Mark the allocation of the high pressure lines to the cylinder. They must always be reinstalled on the same cylinder.
• Note the rules of cleanliness for working on the fuel injection system.
• Always seal any open connections with a suitable cover.
- Disconnect the electrical connectors - arrows - from fuel injectors.
Counter hold the high pressure support at the fuel injector with a wrench when loosening the high pressure line. If the high pressure supports are loosened, it may cause leaks.
- Remove the union nuts for each high pressure line - 1 through 4 - and remove the high pressure line.
- Lay the high pressure lines on a clean surface and cover with a lint-free cotton cloth.
Installing
Loosen the fuel rail and move it slightly. This makes it possible to mount the fuel injection line free of tension. Loosen the fuel rail and move it slightly and lightly turn its respective fuel injector if necessary. The lines must not be bent or under stress. Long term this would cause the line to break.
• The following describes installing new high pressure lines. The high pressure lines can be reused only after the following checks have been performed (refer to - item 9 - in the => [ Fuel Rail and Injector Overview ] Fuel Rail and Injector Overview). The procedure is otherwise identical.
- Loosen the bolts for the fuel rail and make sure the it is possible to move the rail, if this was not done before.
- Loosen the bolts for the tensioning brackets and make sure the it is possible to turn the injectors, if this was not done before.
- Take the high pressure line out of the packaging. Remove the plug and immediately install the line between the high pressure pump and the fuel rail.
- Tighten the high pressure line union nuts on the high pressure pump by hand.
- Make sure the line is installed correctly.
- Proceed the same way with the other fuel injection lines.
- Tighten the components according in the sequence using the socket (T40055).
It is imperative that the high pressure line clamps between the fuel rail and the high pressure pump are installed in the correct positions. Otherwise the vibration or tension in the high pressure line may cause it to break apart.
Installed Position of the High Pressure Line Clamp
- Tighten the clamp to 8 Nm.
After the high pressure line assembly, and when installing a new short engine, it is particularly important to tighten the fuel injector tensioning bracket to the previously mentioned tightening specification, refer to => [ Fuel Rail and Injector Overview ] Fuel Rail and Injector Overview. Only tighten the tensioning brackets hand tight after delivery when assembling the high pressure line in order to align the fuel injector. Engine damage may occur if not observed.
- Press the return line connections carefully onto the injector (check the sealing ring first for damage). The connection must audibly engage. Then carefully press the release bolt downward.
- Fill the fuel system. Refer to => [ Fuel System, Filling and Bleeding ] Fuel System, Filling and Bleeding.
Tightening Sequence and Specification
