Fuel Rail: Service and Repair

13 53 158 Removing And Installing/Replacing Rail (N55)

Special tools required:







WARNING:
Observe warning on cylinder head cover.
Disconnect negative battery terminal (risk of fire due to short circuit on removal).
Electric fuel pump starts up automatically when door is opened.
Carry out installation work on fuel system only with coolant temperature below 40 °C.







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:
When working on the oil, coolant or fuel circuit, you must protect the alternator against dirt contamination.
Cover alternator with suitable materials.
Failure to comply with this procedure may result in an alternator malfunction.







Necessary preliminary tasks:
- Disconnect pressure lines.
- Remove intake silencer housing.







Recycling:
Fuel escapes when fuel lines are detached.
Catch and dispose of escaping fuel.
Observe country-specific waste disposal regulations.







Release wiring harnesses (1) from rail and lay to one side.
Undo clamps (2) from rail.







Slacken nut (1).
Unlock and disconnect plug (2) on high-pressure sensor.
Release screws (3).
Remove rail (4).







Installing the rail:
Rail installation is described separately from removal.







Install (4) rail while manually tightening nuts (3) and bolts (1).

NOTE:
- Rail must still be displaceable on cylinder head.
- Nut (2) must be able to be screwed on easily by hand.

Push on connector for high-pressure sensor (2).







Fitting pressure lines:
(Same procedure for all pressure lines)
Install pressure line (1). Tighten down nuts (2) hand-tight only.

IMPORTANT:
Connect pressure line (1) without tension only.
To ensure distortion-free installation of the pressure line and to avoid damaging the thread, it must be possible for both nuts to be screwed on easily by hand

Reinstall line damper (3).







Tighten down screws (1).
Tightening torque 13 53 2AZ.
Tighten nut (2).
Tightening torque 13 53 8AZ.







Adhere to tightening sequence:
- First tighten down nut (1) on injector.
- Then tighten down nut (2) on rail.

Tighten down nuts with special tool 313 0 161.

IMPORTANT: Reset special tool in early to avoid bending pressure lines.

Tightening torque 13 53 9AZ.







Assemble engine.
Check fuel system for tightness.
Check function of DME.

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