Fuel Injector: Service and Repair
Fuel Injectors
Removing
Special tools, testers and auxiliary items required
• Puller (T10055)
• Guide Sleeve (T10377)
• Socket (T40055)
• Torque Wrench (5-50 Nm) (V.A.G 1331)
• Ratchet, Reversible (V.A.G 1331/1)
- Pay attention to the rules of cleanliness. Refer to => [ Clean Working Conditions ] Clean Working Conditions.
- Remove the engine cover. Refer to => [ Engine Cover ] Engine Cover.
- Remove the protective strip (- item 1 - in the => [ Fuel System Component Overview ] Fuel System Component Overview), if equipped.
- Remove the noise insulation from the cylinder head cover.
- Disconnect the connector - 1 - from the fuel injector(s) to be removed.
- Before removing, clean the return line connection on the fuel injector(s) that will be removed (for example using a commercially available detergent).
- Dry the return line connection.
- Cover the return line connection with a cloth.
- Remove the fuel return line connection(s) from the fuel injector(s) to be removed. Press the connection downward and pull the center piece upward.
Pay attention to cleanliness. Dirt and contaminants must not get into the return lines and the connections on the fuel injector units.
Always protect all opened fuel connections to prevent dirt from getting into them.
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- Remove the high pressure line, - item 5 - in the => [ Fuel System Component Overview ] Fuel System Component Overview between the fuel rail and the fuel injector(s) to be removed.
- Remove the sealing cap bolts, - item 19 - in the => [ Fuel System Component Overview ] Fuel System Component Overview for the fuel injector(s) that will be removed.
- Slightly lift the sealing cap and turn it 90° (1/4 turn) to free access the tensioning place nuts for the fuel injector(s).
When removing the tensioning plate nuts, the nut could fall into the cylinder head. Work very carefully to avoid unnecessary work or damage.
- Remove the tensioning plate nuts for the corresponding fuel injector.
- Position the puller (T10055) with the adapter (T10055/1) as illustrated and remove the fuel injector upward.
Installing
Important information when installing the fuel injectors:
• The following parts, seals or O-rings must be replaced during each removal or installation, or when a fuel injector is being replaced: "Tensioning plate", "copper washer", "fuel injector shaft O-ring" "fuel injector return O-ring"
• The fuel injector must be installed in the same cylinder.
• Check the fuel injectors and installed locations for contamination before assembling.
• The fuel injectors must not have any damage.
• Lubricate all of the O-rings with assembly oil or engine oil before installing.
If a used fuel injector is reinstalled again:
- Spray the tip of the fuel injector with a rust removing spray. Remove the rust or oil particles with a cloth after approximately 5 minutes.
- To remove the used copper washer from the fuel injector, clamp the washer carefully in a vise until the vice jaws prevent the washer from turning. Pull the fuel injector out of the washer by hand with a slight twisting/pulling motion.
- Use a plastic socket to install the copper washer.
- Carefully slide the new O-ring for the fuel return connection onto the connection.
- To remove rust particles on the fuel injector sealing surface, clean the fuel injector bore in the cylinder head with a cloth dampened with engine oil or rust remover. Do not damage the sealing flanges.
- Replace the fuel injector shaft seal using the guide sleeve (T10377).
- Slide the fuel injector sealing cap on.
- Slide the tensioning plate onto the fuel injector and make sure it is positioned correctly. Refer to => [ Tensioning Plate Installed Position ] Fuel System Component Overview.
- Insert the fuel injector in the fuel injector bore.
When installing the tensioning plate nuts, the nut could fall into the cylinder head. Work very carefully to avoid unnecessary work or damage.
- Install the tensioning plate nuts by hand and tighten them. Tightening specification, see - item 17 - in the => [ Fuel System Component Overview ] Fuel System Component Overview.
- Turn the sealing cap to its installed position and tighten the bolts. Tightening specification, see - item 19 - in the => [ Fuel System Component Overview ] Fuel System Component Overview.
- Install the high pressure lines. Refer to => [ High Pressure Lines ] Service and Repair.
• 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 "Guided Functions" in the vehicle diagnostic tester.