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Fuel Filter Replacement
 
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Pelican Technical Article:

Fuel Filter Replacement

Nick Czerula

Time:

2 hours2 hrs

Tab:

$25

Talent:

****

Tools:

Set of sockets (10mm), wrenches, screwdrivers, drain pan

Applicable Models:

BMW Z3 (1996-02)

Parts Required:

Fuel filter

Hot Tip:

Work with a cool engine.

Performance Gain:

Car will run well.

Complementary Modification:

Replace fuel and vacuum hoses

BMW Z3 is equipped with an electrical fuel pump inside the fuel tank. The pump is combined with the right side fuel level sender. The fuel pump delivers high pressure fuel to the fuel injection system in the engine compartment via the fuel filter. System pressure is maintained using a fuel pressure regulator. The supply of fuel from the fuel pump exceeds the requirements of the engine, so excess fuel is returned to the fuel tank via a fuel return line.

The vehicle fuel supply may be contaminated by rust or other impurities. This material is retained by the fuel filter and may eventually restrict the supply of fuel to the engine, resulting in fuel starvation or engine stuttering. Replace the fuel filter every 15,000 miles or once a year. Follow this article carefully and you too will have a better running (less stuttering) engine.

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. 

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.

The filter is located beneath the vehicle on the left side, mounted on the frame rail.

With your vehicle raised and supported safely, look under vehicle in area of left floor, you will see the fuel filter cover.
Figure 1

With your vehicle raised and supported safely, look under vehicle in area of left floor, you will see the fuel filter cover. The fuel filter is mounted behind cover (green arrow). I will show you how to remove it later in this tech article.

Early fuel filter assembly: This style has one fuel line (yellow arrows) connecting at each end and the running losses valve (green arrow) at the front.
Figure 2

Early fuel filter assembly: This style has one fuel line (yellow arrows) connecting at each end and the running losses valve (green arrow) at the front.

Late fuel filter assembly: This filter has three fuel lines connected, two at the back (red arrows) and one at the front (yellow arrow) and an integrated fuel pressure regulator (green arrow).
Figure 3

Late fuel filter assembly: This filter has three fuel lines connected, two at the back (red arrows) and one at the front (yellow arrow) and an integrated fuel pressure regulator (green arrow).

The running losses valve (green arrow) is located in front of fuel filter on early Z3 models.
Figure 4

The running losses valve (green arrow) is located in front of fuel filter on early Z3 models. These valves are solid and do not fail that often. However, the vacuum line to the fuel pressure regulator does fail. There are usually no symptoms when this vacuum line fails and goes unnoticed until you replace your fuel filter. If you find this line has failed, replace vacuum hose with new. Before replacing your fuel filter, have a suitable container available to catch any fuel that spills when fuel lines are loosened or removed. Have clean rags available to wipe up excess fuel and have a fire extinguisher handy. Eye and hand protection are a must and if fuel comes in contact with your skin, wash it off immediately. Also, make sure to work in a well ventilated area and do not allow fuel vapors to gather. This is a repair best suited for outdoor, on solid level ground. ItÂ's a good idea to relieve fuel system pressure before beginning. This will minimize the amount of fuel spilled. The best way to relieve fuel system pressure is to remove the fuel pump fuse and run the vehicle until the engine stalls.

Remove fuses #13 and #18 (check that this fuse applies to you vehicle).
Figure 5

Remove fuses #13 and #18 (check that this fuse applies to you vehicle). Use the fuse application chart located below your fuses to identify fuse number. Start and run engine until it stalls. Once engine stalls, attempt to start again, if it does not start, fuel system pressure has been relieved. Keep in mind; this does not remove all the fuel from the fuel lines, only the pressure. So you still need to be prepared to catch leaking fuel when fuel lines are disconnected. Disconnect negative (-) battery cable. See our tech article on Battery connection notes.

Remove the four 10mm fuel filter cover mounting fasteners, then remove fuel filter cover.
Figure 6

Remove the four 10mm fuel filter cover mounting fasteners, then remove fuel filter cover. (green arrows) Clean fuel filter, fuel lines, and clamps thoroughly. This will help prevent dirt from entering fuel system. I like to start with the inlet side of fuel filter. This way you can monitor condition of fuel heading into the filter. Look for any contaminants, water, or rust. Working at inlet side of fuel filter, remove fuel line clamp(s), then disconnect fuel line from filter, and allow fuel to drain into suitable container. Next check that the fuel is clean and free from contaminants.

Early model fuel filters have a single inlet hose.
Figure 7

Early model fuel filters have a single inlet hose. (green arrow)

Late model fuel filters have two inlet hoses.
Figure 8

Late model fuel filters have two inlet hoses. (green arrows) If you find debris in your fuel, the fuel tank will need to be serviced or replaced. There are fuel tank shops that steam clean the interior of the tank if needed. Next, remove the outlet fuel line from the fuel filter, and allow fuel to drain into suitable container.

Early model fuel filters have a single outlet hose.
Figure 9

Early model fuel filters have a single outlet hose.(green arrow)

Late model fuel filters have single outlet hose (green arrow) and a vacuum hose (yellow arrow).
Figure 10

Late model fuel filters have single outlet hose (green arrow) and a vacuum hose (yellow arrow).

Next, lever the fuel line out of the holder (if needed) using a flathead screwdriver.
Figure 11

Next, lever the fuel line out of the holder (if needed) using a flathead screwdriver. This allows access to the mounting bracket nut. Then, remove the 10mm nut (green arrow) for the fuel filter mounting bracket and remove fuel filter from vehicle. Quickly place fuel filter into container and allow remaining fuel to drain. Give your work space at least 15 minutes to air out before installing new filter.

When installing new filter, be sure to get orientation correct.
Figure 12

When installing new filter, be sure to get orientation correct. The inlet and outlet are usually marked.

Depending on fuel filter manufacturer, there may also be an arrow facing in direction of fuel flow.
Figure 13

Depending on fuel filter manufacturer, there may also be an arrow facing in direction of fuel flow. Before installing, inspect condition of rubber fuel lines. If lines show signs of cracking or wear, replace with new. Install new fuel filter in fuel filter bracket and tighten 10mm fastener. Using new hose clamps, install fuel lines (starting with inlet). Tighten hose clamps being careful not to over-torque. Once all fuel lines are connected and tight, reinstall fuel pump fuse and start engine. Let engine run for about 1 minute. Then recheck your work and confirm there are no fuel leaks. Once you are sure no fuel leaks are present, reinstall the fuel filter cover. Clean up any spilled fuel remaining and properly dispose of the old fuel filter.

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Comments and Suggestions:
Dork Comments: Apologies - there are only 4 nuts. On refitting with better visibility I noticed that the larger one is for an adjacent shield. However for some reason I couldn't remove the filter shield without removing the larger nut. Maybe there was an overlap.
September 15, 2017
Dork Comments: Thanks for that. Just thought I would share my experiences when fitting a fuel filter to my 1999 2.0 litre 6 cylinder Z3 using your guidance in the hope that it may reassure someone who is as apprehensive as I was. It is much simpler than I anticipated. There were 5 nuts holding the shield not 4 and one has a larger diameter – may be worth noting where it fits. There is no need to remove the bracket – the filter slides out easily once the bracket is loose. I used the fuse removal procedure but the car would not start with the fuses removed. In any eventful there was only a cupful of fuel leakage. I replaced the hoses 7.6mm and clips using a smear of TF2 inside the hoses to ease fitting.
September 14, 2017
Dork Comments: Not quite sure how much fuel will leak having followed your fuse removal/engine run procedure. For example will the fuel tank completely drain? How big a container will I need to catch it? Should I use hose clamps? Grateful for any clarification - thanks.
September 11, 2017
  Followup from the Pelican Staff: removing the fuse ONLY removes pressure from the fuel line, You have to manually drain the tank using a fluid removal pump. - Nick at Pelican Parts  
Liu Comments: very helpful! Thank you!
May 25, 2015
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help.
- Nick at Pelican Parts
 
Mr Liu Comments: "Replace fuel and vacuum hoses"??

what kind of hoses can be used for the fuel and vacum? I have little knowledge of the hoses. Any regular tube will be ok??

Thank you.
May 21, 2015
  Followup from the Pelican Staff: Fuel and vacuum line are usually black nitrile and braided.

Give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
 

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Page last updated: Tue 9/19/2017 02:08:14 AM