Removal and Replacement
Fuel Injectors
Special tools, testers and auxiliary items required
• Torque Wrench 5-50 Nm (V.A.G 1331)
• Ratchet, Reversible (V.A.G 1331/1)
• Tool Insert, AF 17 (V.A.G 1331/6)
• Socket (T40055)
• Puller (T10055) with Adapter (T10055/1)
• Guide Sleeve (T10377)
Removing
• Follow the guidelines for a clean working environment when working on the fuel system. Refer to => [ Fuel System ] Fuel System.
• Always follow these rules before and during work.
- Remove engine cover. Refer to => [ Engine Cover ] Service and Repair.
- Remove the noise insulation from the cylinder head cover.
• Mark the allocation of the injectors to the cylinder. They must always be re-installed on the same cylinder.
• Note rules of cleanliness for working on the fuel injection system.
• Always seal any open connections with a suitable cover.
- Push both brackets down and at the same time pull the release bolts upwards - arrow - and remove the return line connections on the injector units.
• If it is not possible to pull the return line connection upward, open the connection by rotating it with a small screwdriver.
- Disconnect the connectors - 1 - on the injector units to be removed.
- Remove the high pressure line union nuts on the injectors using the (T40055).
- Loosen the union nuts on the fuel rail high pressure lines using the (V.A.G 1331/6).
- Remove the injector covers - arrows -.
- Pull the covers upward and turn them 1/4 turn (90°).
When removing the fuel injector nuts, the nut could fall into the cylinder head. Work very carefully to avoid unnecessary work or damage.
- Remove the injector tensioning brackets - arrows -.
- Position the (T10055) with the adapter (T10055/1) as illustration and remove the fuel injector upward by tapping.
- Place the injectors on a clean cloth.
Installing New Fuel Injectors
The following must be replaced when installing a new fuel injection:
• Tensioning bracket
• Copper sealing ring
• O-ring for the fuel injector shaft
• O-ring for the fuel return line connection
• When using the high pressure line again, pay attention to the cylinder marking.
• The high pressure lines can be reused only after the following checks:
• Check the sealing cone on each high pressure line for deformation and cracks.
• The bores for the lines must not be deformed, narrowed or damaged.
• Do not use corroded lines again.
Installing used fuel injectors
The following must be replaced when installing a used fuel injector:
• Tensioning bracket
• Copper sealing ring
• O-ring for the fuel injector shaft
• O-ring for the fuel return line connection
- Spray the tip of the fuel injector with a rust removing spray. Remove the rust or oil particles with a rag after approximately 5 minutes.
- If an injector is very dirty, clean the tips around the copper sealing ring with a soft brush. Do not let the brush come in contact with the holes for the jets.
- To remove the used copper sealing ring from the fuel injector, clamp the sealing ring carefully in a vise until the clamping jaws on the vise prevent the ring from turning. Pull the fuel injector out of the copper sealing ring by hand with slight twisting and pulling motions.
- Use a scraper to remove any deposits under the copper sealing ring.
Danger of causing damage to the sealing surface on the fuel injector.
• To remove the rust particles on the fuel injector sealing surface, clean the fuel injector duct in the cylinder head with a cloth dampened with engine oil or rust remover.
- Replace the fuel injector shaft seal using the (T10377).
- Carefully slide the lubricated O-ring onto the fuel return line connection to prevent damaging it.
- Install the fuel injectors.
- Tighten the union nuts for the high-pressure lines by hand. Make sure it fits free-of-tension.
- Use the (V.A.G 1331) and (V.A.G 1331/1) and (T40055) to tighten the high pressure lines to the injectors.
- Tighten the high pressure lines on the fuel rail using a (V.A.G 1331) with a (V.A.G 1331/6).
• Pay attention to the tightening specification, refer to => [ High Pressure Lines ] Service and Repair
• Tightening specification, refer to => [ Fuel System Overview ] Fuel System Overview, Diesel
- Press the connections for the return lines carefully over the fuel injector seals (check the seal for damage beforehand). The connection must engage audibly. Then press the release pin down carefully.
The "injector quantity calibration" and the "injection pressure calibration" for the new injectors must be programmed into the Engine Control Module (ECM) after replacing one or more injectors.
Check all the other injectors as well regarding their "injector quantity calibration" and "injection pressure calibration" to make sure all comparison values have been entered correctly. If the correct comparison value has been stored in the ECM, then these comparison value must never be re-entered.
Fuel System, Bleeding and Performing a Leak Test
• The high pressure connections must not be opened; the fuel system bleeds itself.
- Let the engine run a few minutes at idle and then stop it.
- Turn off ignition.
- Check the entire fuel system and the 4 return line connections for leaks.
If there are leaks even though the correct tightening specification was used, replace the affected component.
• The return lines may only be replaced completely with the pressure retention valve.
- Perform a road test where the accelerator pedal is pressed all the way down at least one time. Then check the high pressure area again for leaks.
• If there is still air in the fuel system, the engine may switch to emergency mode during the road test. Turn off the engine and erase the DTC memory. Then continue the road test.