Fuel Injectors
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)
• Puller (T10055) with adapter (T10055/1)
• Socket (T40055)
Removing
- Remove engine cover. Refer to => [ Engine Cover ] Service and Repair.
• The following shows the removing and installation of Piezo injectors on the cylinder bank 2 (left). The procedure on the opposite side is identical except for a few steps.
• The air guide hose and the upper section of the air filter housing must removed in order to remove and install the Piezo injectors on cylinder bank 1 (right).
• 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.
• Mark the allocation of the injectors to the cylinder. They must always be re-installed on the same cylinder.
• Always seal any open connections with a suitable cover.
- Disconnect the return line connection on the injector by pressing both tabs downward and pulling the center piece at the same time upward - arrows -.
• Maintain clean working conditions. Dirt and contaminants must not enter the return lines and the connections on the fuel injectors.
- Disconnect the connector on the injector to be removed.
- Remove the high pressure line union nuts - 1 - on the injectors using the (T40055).
- Loosen the high pressure line union nuts - 2 - on the fuel rail using the (V.A.G 1331/5).
- Remove the injector covers - arrows -.
- Pull the covers upward and turn them 1/4 turn (90°).
- Remove the injector tensioning brackets - arrows -.
- Remove the injectors using the (T10055) and (T10055/1).
- 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
• Lubricate all of the O-rings with assembly oil or engine oil before installing.
• 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:
• 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.
- Install the new copper sealing ring with a plastic bushing.
- Replace the O-rings on all the return line connections.
• Lubricate all of the O-rings with assembly oil or engine oil before installing.
To remove 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. Do not damage the sealing flanges.
- 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.
- 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.
The "injector quantity calibration" and the "injection pressure calibration" for the new injectors must be must be programmed into the Engine Control Module (ECM) after replacing one or more injectors. Refer to => [ Injector Quantity Calibration and Injector Pressure Calibration, Performing an Adaptation ] Programming and Relearning.
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 have been stored in the ECM, then these comparison value must never be re-entered.
Fuel System, Bleeding and Performing a Leak Test
- Let the engine run a few minutes at idle without pressing the accelerator pedal and then stop the engine.
• The high pressure connections must not be opened; the fuel system bleeds itself.
- Turn off ignition.
- Carefully check the entire fuel system and the return line connections (6 in total) for leaks. The return lines and check valve must be replaced completely.
If there are leaks even though the correct tightening specification was used, replace the affected component.
- 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 Diagnostic Trouble Code (DTC) memory. Then continue the road test.
• Tightening specifications: fuel system, assembly overview, refer to => [ Fuel System Overview ] Fuel System Overview
- After the road test, check the DTC memory again.