Removal and Replacement

Fuel pump

WARNING: Removal of the fuel pressure regulator involves partial dismantling of the car's fuel system. The following points must therefore be observed in connection with this work:
- Work only in a well-ventilated area. If approved equipment for the extraction of fuel vapors is available, be sure to use it.
- Wear suitable gloves Prolonged contact with fuel can cause skin irritation or dermatitis.
- Keep a class BE fire extinguisher near at hand. Be mindful of the danger of sparks caused by short circuits and when connecting and disconnecting leads in electrical circuits.
- No smoking anywhere in the vicinity,
- Wear protective goggles.

To remove

Important
The car should be parked on a level surface. If the tank is full and the car is jacked up at the rear when the pump is removed, it is very likely that fuel will run out.
Use absorbent paper and perhaps a receptacle to protect the carpeting when the pump is removed as fuel could easily run out or be spilt.





1 Raise the rear seat cushions and fold the carpeting out of the way.
2 Remove the fuel pump cover.
3 Unplug the upper connector as shown.

Important
The connector on the pump must not be removed.





4 Carefully ease non-return valves with fuel lines off the pump. Move the yellow hooks carefully aside, using a screwdriver. The white one represents the delivery side and is marked "Pressure" on the pump. The black one is the return side and marked "Return" on the pump. Bend them aside and secure them under the sheet metal fold.





5 Remove the screw ring, using the special tool (part No. 83 94 462).





6 Lift up the pump until the top of it is about 50 mm above the fuel tank. Then turn the pump clockwise about 80° and carefully remove it. Hold paper or a cloth ready to catch any fuel that spills out.
7 Transfer the pump to a suitable receptacle and pour off the fuel.





To fit

1 Clean sealing surfaces.
2 Fit a new O-ring in the groove in the tank.

Important
It is essential to the operation of the fuel level sensor for the pump unit to be correctly positioned.





3 Carefully lower the pump into its correct position, making sure that the alignment marks on the tank and fuel pump are opposite each other. Carefully press the pump down into position.
4 Lubricate the screw ring's threads and the top of the pump with non-acidic petroleum jelly (Vaseline) to prevent the pump from turning when the screw ring is tightened.
5 Fit the screw ring in place and tighten it with special tool No. 83 94 462.
Tightening torque 75 Nm (55 lbf ft).





6 Inspect the O-rings and smear non-acidic petroleum jelly (Vaseline) on them and the fuel line connections and connect them to the pump. Try to avoid spilling fuel.
7 Make sure that the yellow hooks have snapped in place over the connections.
8 Plug in the connector and spray it with a contact cleaner like Kontakt 61 (part No. 30 04 520).
9 Check that the pump works properly and that it does not leak.
10 Fit the fuel pump cover, return the rear seat cushions to their places and fold back the carpeting.





Checking the non-return valve

1 Remove the valve cap. Connect the pressure gauge (special tool, part No. 83 93 852) and adapter (special tool, part No. 83 94 744) with pressure gauge (special tool, part No. 83 93 852) to the fuel rail with the "safety" on. Use the tool with the "safety" off





2 Activate the fuel pump with the diagnostic tool.
3 Run the pump manually until the pressure gauge no longer rises.
4 Note the pressure gauge reading. Turn off the pump. Residual pressure after 20 minutes should be at least 2.3 bar (33 psi).
5 If the residual pressure is too low, check the non-return valve by detaching it from the pump outlet to see whether it leaks.
6 Remove the tool (part No. 83 93 886).

Changing the non-return valve

Important
If both non-return valves on the delivery and return lines are changed it is important to make sure that the right valve is fitted on the right line.





1 Expose the non-return valve.
2 Cut the fuel delivery line at the pump nipple as shown using a razor blade or sharp knife.





3 Fit the tool (part No. 83 94 546) on the fuel line.
4 Press the new non-return valve into the line with the fitting facing the pump.
5 Fit new O-rings on the valve. Lubricate with non-acidic petroleum jelly (Vaseline).
6 Plug in the connector and spray it with contact cleaner Kontakt 61 (part No. 30 04 520). Connect the fuel lines.





Checking the fuel gauge float arm position

With the pump placed on a level surface, the distance between the surface and the bottom of the float should be 0-3 mm.
The sensor resistance should be:
- Tank empty, float in bottom position: 50 ± 1.5 ohms.
- Tank full, float in top position: 425 ± 6.5 ohms.