Fuel Pump: Service and Repair
13 51 017 - Removing and installing or replacing high-pressure fuel pump (N54, N53)
Special tools required:
- 11 8 610 11 8 610 Wrench Socket, Hexagon Socket WAF 5
- 13 5 020 13 5 020 Wrench WAF 17
- 13 5 281
- 13 5 282
- 32 1 270 32 1 270 Plugs (Set)
Warning!
Observe warning on cylinder head cover.
Disconnect battery negative terminal Disconnecting and Connecting Battery Negative Lead (risk of fire due to short-circuiting on removal).
Electric fuel pump starts up automatically each time 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 velocity 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 before removing pipes or individual components.
- Use only fluff-free cloths.
- Seal all fuel system openings with protective caps or plugs.
Necessary preliminary tasks:
- Remove intake air manifold Service and Repair
Recycling:
Fuel escapes when fuel lines are detached.
Catch and dispose of escaping fuel.
Observe country-specific waste-disposal regulations.
N53 only:
Lay exhaust gas recirculation (1) upwards to one side.Do not remove.
Unlock plug (1) and remove.
Unlock and detach fuel line (2).
Catch and dispose of escaping fuel.
Seal fuel lines with special tools 13 5 281 and 13 5 282.
Slacken nut (1).
Release screw (2).
Installation Note:
- Replace aluminium screw.
Remove feed line (3).
Seal feed line with matching plug from special tool kit 32 1 270 32 1 270 Plugs (Set).
Warning!
Wear full face guard and protective gloves.
Slacken nut (1).
Slacken nut (2).
Release screw (3).
Disconnect high-pressure line (4).
Seal connections of high-pressure line (4) with matching plugs from special tool kit 32 1 270 32 1 270 Plugs (Set).
Seal fuel line connections of high-pressure pump (1) with matching plugs from special tool kit 32 1 270 32 1 270 Plugs (Set).
Release screws with special tool 11 8 610 11 8 610 Wrench Socket, Hexagon Socket WAF 5.
Detach high-pressure pump (1) and remove.
Engine oil can escape when pump is detached; have a cleaning cloth ready.
Installing high-pressure pump:
Installation of high-pressure pump is described separately from removal.
Replace sealing ring (1).
Clean contact faces.
When installing, turn high-pressure pump (1) if necessary in direction of arrow until bores for screws are flush.
Important!
Tighten screws of high-pressure pump (1) with special tool 11 8 610 11 8 610 Wrench Socket, Hexagon Socket WAF 5 hand-tight only.
It must still be possible to turn the high-pressure pump at the flange!
This prevents twisting when high-pressure line (4) (Fig. R13 13 85) is tightened.
Copper seals that may be fitted on the high-pressure line are no longer needed and must be removed. If reusing pressure line, lightly grease threads of pressure connections. Threads of new pressure lines are already coated.
Pre-install high-pressure line (4).
In so doing, tighten screw connections (Fig. R13 13 85) hand-tight only (it must still be possible to move the high-pressure line at the holder).
Only when high-pressure pump (1) has if necessary turned into position and is thus pre-installed without twisting with high pressure-line (4) should screws of high-pressure pump (1) be tightened down with special tool 11 8 610 11 8 610 Wrench Socket, Hexagon Socket WAF 5.
Tightening torque 13 51 1AZ 13 51 Injection Pump, Control.
Important!
Follow sequence of screw connections:
1. Tighten down nut (1) with special tool 13 5 020 13 5 020 Wrench WAF 17. Tightening torque 13 53 7AZ 13 53 Fuel Injection Nozzles and Pipes.
2. Tighten nut (2). Tightening torque 13 53 7AZ 13 53 Fuel Injection Nozzles and Pipes.
3. Tighten down screw (3) for holder. Tightening torque 13 53 2AZ 13 53 Fuel Injection Nozzles and Pipes.
Note:
Feed lines with soldered holder must be replaced by new version with elastomer clamp holder. Observe installation position of fuel low-pressure sensor. Lines for solenoid switches are laid behind fuel line.
Install feed line (3).
In so doing, tighten screw connection hand-tight only
Important!
Follow sequence of screw connections:
1. Tighten down nut (1) with special tool 13 5 020 13 5 020 Wrench WAF 17. Tightening torque 13 53 6AZ 13 53 Fuel Injection Nozzles and Pipes.
2. Tighten screw (2). Replace aluminium screw. Tightening torque 13 53 9AZ 13 53 Fuel Injection Nozzles and Pipes.
Assemble engine.
Check fuel system for leaks.
Check function of DME.