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Fuel Pump Replacement
 
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Pelican Technical Article:

Fuel Pump Replacement

Nick Czerula

Time:

3 hours3 hrs

Tab:

$ 350

Talent:

*****

Tools:

Phillips & flathead screwdriver, socket set

Applicable Models:

BMW Z3 Coupe/Conv (1996-02)

Parts Required:

Fuel pump, fuel pump sealing O-ring

Hot Tip:

Cover interior in plastic to prevent fuel spills onto carpet

Performance Gain:

Repair faulty fuel pump

Complementary Modification:

Replace fuel filter at same time

The fuel supply system in a BMW Z3 consists of: 

  • Fuel tank
  • Fuel filler with associated breathing and venting pipes
  • Evaporative emissions control valve and pressure pump
  • High-pressure fuel pump assembly with fuel filter and fuel level senders
  • Fuel pump relay
  • Fuel pressure regulator
  • Fuel rail and electric fuel injectors

A faulty fuel pump can cause poor engine performance and hard starting problems. When it fails completely, you may be left with an engine that doesn't start. If you suspect your fuel pump has failed, you can confirm the fuel pump has received the correct voltage when commanded ON by the fuel pump relay using a digital volt ohm-meter (DVOM). If the correct voltage is present, but the pump does not activate, it is likely faulty. Use the DVOM in conjunction with a wiring diagram to determine the correct terminals for testing. See our tech article on fuel pump testing.

Accessing the fuel pump terminals  or replacing the fuel pump on a BMW Z3 can be done without removing the fuel tank. There are access panels underneath the rear seat cushion that allow servicing. The fuel tank is two-lobed. There are two fuel level senders, one in each lobe on the left and right sides underneath the rear seat cushion. The left fuel tank lobe holds the fuel level sender and fuel filter, while the right tank lobe holds the fuel pump.

To avoid marring the paint and trim, work with a plastic prying tool or wrap a screwdriver tip with masking tape before prying out body or interior items.

Keep in mind that when your car was serviced before, parts may have been replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have, so be prepared with different size sockets and wrenches. 

When performing electrical tests, be sure to use a digital instrument such as DVOM. Using an analog device may lead to damage to sensitive electronic components.

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If you're working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Do not work on your vehicle if you feel the task is beyond your ability. 

Vehicle models change and evolve, as they grow older, so the vehicle shown in our illustrations may vary slightly from yours. If something seems different, let us know and share your info to help other users. Do you have questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

To start this project, it is best to replace your fuel pump with the fuel tank drained. This reduces the amount of possible spilled fuel and fuel vapors. When replacing, work in a well ventilated area. Working outdoors is a good choice. Do not use incandescent work lights or power tools, fuel and fuel vapors are highly combustible.

Disconnect the negative battery cable. See our tech article on battery replacing and reconnecting notes.

Remove the fuel cap. Then slide an anti-static siphon hose down the fuel filler neck. Once the hose has bottomed out, pump fuel out of the fuel tank into a suitable storage container. If you are unsure of the amount of fuel in your tank. You can monitor the fuel level via the fuel level sender units. As fuel level drops, the fuel level sender resistance drops. You can measure this across the terminals at both sender units with a digital volt / ohm meter (DVOM). You will need a wiring diagram from a repair manual.

Remove the right (passenger) seat. See our tech article on seat and seat belt buckle removing.

Working behind right side seat (passenger seat), peel carpet away from body.
Figure 1

Working behind right side seat (passenger seat), peel carpet away from body.

Remove four Phillips head screws from the access panel (green arrows).
Figure 2

Remove four Phillips head screws from the access panel (green arrows).

Remove access panel lid from body by lifting up.
Figure 3

Remove access panel lid from body by lifting up. Move away enough to access electrical connector on fuel pump module.

Disconnect fuel pump electrical connector (green arrow) by sliding locking tab using a flathead screwdriver, then pulling connector off fuel pump module.
Figure 4

Disconnect fuel pump electrical connector (green arrow) by sliding locking tab using a flathead screwdriver, then pulling connector off fuel pump module.

Disconnect the remaining electrical connector by squeezing locking tabs and pulling connector apart.
Figure 5

Disconnect the remaining electrical connector by squeezing locking tabs and pulling connector apart.

Once I have access to the fuel pump module lock ring I vacuum any dirt or debris from the surrounding area.
Figure 6

Once I have access to the fuel pump module lock ring I vacuum any dirt or debris from the surrounding area. This helps to keep the interior of the fuel tank clean.

Then I hold the carpet flap open using a bungee cord.
Figure 7

Then I hold the carpet flap open using a bungee cord. I also cover the interior of the vehicle with plastic to avoid getting fuel on the carpet.

Using a pair of needle nose pliers, pull the plastic caps (green arrows) off the fuel line clamps (if equipped).
Figure 8

Using a pair of needle nose pliers, pull the plastic caps (green arrows) off the fuel line clamps (if equipped). Loosening the fuel line hose clamps requires a special socket. But hereâÂÂÂs the good news, you can get these off without it. When I didnâÂÂÂt have the right socket, I would use my 6mm nut driver and tilt it just a bit so it would grab the hose clamp end. Some of these clamps have enough of an edge to use a flathead screwdriver to remove them. This would allow me to loosen both clamps. When reinstalling the hose, replace the factory single-use clamp with a standard fuel injection style clamp.

Slide hose partially off fuel pump module.
Figure 9

Slide hose partially off fuel pump module.

Cover hose with rag, and remove the remainder of way off fuel pump module.
Figure 10

Cover hose with rag, and remove the remainder of way off fuel pump module. This will help to contain any spilled fuel when hose is removed.

Next you have to unscrew fuel pump module threaded collar (green arrow).
Figure 11

Next you have to unscrew fuel pump module threaded collar (green arrow). There is a BMW special tool (number 16 1 022) made to do this, however if you do not have this tool you can use a dull flathead screwdriver or a dull chisel and a rubber mallet. Be sure the tool is dull, the collar is plastic and you can break it. Note the white mark next to the green arrow. I also mark the collar location so I know about how tight it has to be when reinstalling it.

Using the dull chisel screwdriver and a rubber mallet, tap threaded collar on one of the ridges counter-clockwise to loosen.
Figure 12

Using the dull chisel screwdriver and a rubber mallet, tap threaded collar on one of the ridges counter-clockwise to loosen. Once loose, unscrew the remainder of the way by hand. If collar is damaged during this process, you will need to replace it with a new part.

Slowly lift fuel pump module up and out of fuel tank.
Figure 13

Slowly lift fuel pump module up and out of fuel tank. Have a bucket or plastic bin inside the vehicle with you. Catch any dripping fuel with a cloth as you remove it, then immediately place fuel pump module in bucket to minimize spilled fuel.

When installing, replace fuel pump assembly sealing O-ring.
Figure 14

When installing, replace fuel pump assembly sealing O-ring. Be sure O-ring is properly installed on fuel tank before installing fuel pump (green arrow). Slide new fuel pump assembly with sealing O-ring into fuel tank. Hand tighten threaded collar. Then use BMW special tool 16 1 022 to tighten threaded collar. Or tap tight (clockwise) with dull chisel and a rubber mallet. Connect fuel line with new hose clamp. Be sure hose clamp is for high pressure fuel lines. Connect electrical connector and reassemble interior. Fill fuel tank with about 2 gallons of fuel before attempting to start. Once you are sure fuel pump is operating normally, fill remainder of fuel tank and check for leaks.

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Comments and Suggestions:
Al Comments: Is there an additional replaceable sending unit on drivers side of fuel tank?
November 28, 2016
  Followup from the Pelican Staff: On what model and year vehicle? - Nick at Pelican Parts  
yorkinmadoc Comments: First class guide, huge thanks for all the help.
July 25, 2016
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.

- Nick at Pelican Parts
 
BluesFan44 Comments: Followup: The garage that did the first replacement didn't indicate there was anything loose in the tank. That was going to be part of my replacement attempt.
July 8, 2016
  Followup from the Pelican Staff: if something is loose n the tank, the tank will likely have to be replaced. As the slosh guards are not serviceable. - Nick at Pelican Parts  
BluesFan44 Comments: My pump works but the sending unit is broken, gauge always reads E. A local garage tried to replace the pump/sender, but it immediately broke again. When I got an estimate from a BMW-specific shop, they mentioned that there was an extra step for Z3s. Do you have any info on what this would be?
July 8, 2016
  Followup from the Pelican Staff: No. I would need to know specifically what they are talking about. How did it break? Is something loose in the tank? - Nick at Pelican Parts  
Steveareno Comments: I have a 1996 Z3. I seldom drive it, so I have it hooked-up to a trickle charger. I have the charger power cord coming out of the trunk. I have the trunk propped slightly open to allow sufficient room for the power cord to pass through. I would like to run the power cord through the interior of the car, and then through the driver's side window. This way I could keep the trunk permanently closed. Then All I would have to do is unplug the power cord and back the car out. So, if I've made my myself clear so far, here is my question. Can I drill through the access panel, then run the charger power cord through this hole, and into the passenger compartment? Is there a better or easier location in the car to drill through so that my power cord can penetrate from the passenger compartment to the trunk?
July 7, 2016
  Followup from the Pelican Staff: I would assume there is a bulkhead for the factory wiring. I would use that. You may need to go out the bottom of the trunk, then through the floor where the opening is. Remove the trunk interior trim and follow the battery and electrical harnesses. - Nick at Pelican Parts  
Jim L Comments: This article is a true God-send. Thanks Pelican. You ARE the best!
J L
January 21, 2016
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
pargan R. Pawar Comments: This article of Fuel pump removal and safety replacing the new fuel pump was very helpful
February 15, 2015
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 

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Page last updated: Wed 12/7/2016 02:07:28 AM