Fuel Injector: Service and Repair
13 53 310 Removing and installing or replacing one fuel injector in fuel injection system (N18)
Special tools required:
WARNING:
Disconnect battery negative terminal (risk of fire due to short-circuiting on removal)
Carry out installation work on fuel system only with coolant temperature below 40 °C.
Only perform this repair work on an engine that has cooled down. Risk of burning.
IMPORTANT:
Wear full face guard and protective gloves.
Fuel can emerge spontaneously at high speed when the high pressure line is released.
IMPORTANT:
Adhere to conditions of absolute cleanliness when working on the high-pressure fuel system.
Introduced contaminants can cause malfunctions in the system.
- Do not allow any dirt particles or foreign bodies to get into the system.
- Remove all traces of dirt contamination before removing lines or separate components.
- Use only fluff-free cloths.
- Seal all fuel system openings with protective caps or plugs.
IMPORTANT:
Wear safety goggles.
Oil and dirt particles may get into your eyes.
After removing the injectors, clean the injector shafts with compressed air.
Necessary preliminary tasks:
- Remove high pressure rail.
Recycling:
Fuel escapes when fuel lines are detached.
Catch and dispose of escaping fuel.
Observe country-specific waste disposal regulations.
Removal:
Remove hold-down device (1) and discard.
Pull up fuel injector (2) to remove.
Procedure in event of stuck injectors:
NOTE:
The following procedure applies to all injectors.
For purposes of clarity, illustration shows and description refers to the removed engine.
Mount special tool 13 0 231 with lettering "Top" facing upwards.
Mount special tool 13 0 232 .
To secure injector, turn nut (1) by hand until noticeable resistance is felt.
13 0 232Turn nut on special tool several turns until injector has been released from hole.
Remove special tool.
Remove injector.
The fuel injector installation procedure is described separately.
Before installing injector (1), replace decoupling element (2).
Installation:
Installation note:
- Make sure guide pin (3) of fuel injector (2) is correctly positioned in designated bore hole (4) in cylinder head
- Replace sealing ring (6) and support ring (5), making sure support ring (5) is seated correctly
- Replace hold-down device (1)
- Replace Teflon sealing ring
Replacing Teflon sealing ring:
NOTE: N53 Depiction of engine, procedure for N18 engine identical.
Before replacing Teflon sealing ring (1), make sure hands and work surface are clean and free of oil.
Avoid mechanical contact with injector tip (2).
Remove Teflon sealing ring (1) from injector (2) with special tool 13 0 191.
Use a fluff-free cloth only to remove combustion residues from cylindrical part of injector tip (do not use ultrasound or other tools/agents).
Do not clean injector tip (2).
NOTE: N53 Depiction of engine, procedure for N18 engine identical.
Slide new Teflon sealing ring (1) 13 0 195onto mounting taper .
NOTE: N53 Depiction of engine, procedure for N18 engine identical.
User fingers and mounting taper 13 0 195 to slide Teflon sealing ring (1) onto injector (2).
NOTE:
- Do not use fingernails to slide on Teflon sealing ring.
- Do not use any lubricants.
- The sealing ring is expanded when slid on.
NOTE: N53 Depiction of engine, procedure for N18 engine identical.
To bring the expanded Teflon sealing ring to its installation dimension, slide three assembly sleeves with decreasing diameters onto the injector.
Slide assembly sleeve (1) with large opening first onto injector (2).
Do not use any lubricating agents.
NOTE: N53 Depiction of engine, procedure for N18 engine identical.
First slide assembly sleeve 13 0 192 (large diameter) onto injector (1).
Then slide assembly sleeve 13 0 193 (medium diameter) onto injector (1).
NOTE: N53 Depiction of engine, procedure for N18 engine identical.
Finally, press injector (1) into assembly sleeve 13 0 194 (small diameter).
Assemble engine.
Check fuel system for tightness.
Check function of DME.