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Thread: Fuel Pressure Regulator Install -- 99 M3

  1. #1
    Join Date
    Jul 2001
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    Adjustable Fuel Pressure Regulator Install -- 99 M3

    Background:

    I've gone through 2 stock FPRs in 4 months. My fuel meter showed 50 PSI at idle, vac attached, and went to 60 PSI at 0 vac 0 boost. IN other words, there were two pressures and both were wrong.

    The ES TS kit I have in the car features a Walbro 255 fuel pump. Marco, Thejelvie and others have said there are reports of the stock FPR not holding up to a Walbro. Although Nick G Josh and others use a Walbro without enough reports of trouble to notice, after trying to rule everything else out I said hell with it and took Neil's lead and installed an Aeromotive FPR. Thanks to Nick G for the suggestion on removing the 3/2 valve.

    One lingering question was whether the 3/2 directional valve might have been a culprit, but in true FI fashion I decided to pay $450 for the Aeromotive and install instead of seeing if the $113 3/2 valve was the guilty party.

    I got a few suggestions for where to stick it, but no specifics that would fit my car -- so I installed it in the stock FPR location.


    Parts needed:
    • Aeromotive FPR -- AEI-13109
    • Aeromotive -- 6an o-ring w/ 7 mm hose barb
    • Aeromotive 6an o-ring plug
    • X brand 6an o-ring to right angle hose barb -- (A missing link, the solution I put in the car was a no-other option weekend install solution -- before doing this get another right angle fuel barb than I used.
    • X brand elbow vacuum fitting.
    • About 3 feet of 5/16 fuel injection hose
    • Advanced Tool Design Fuel injection tester -- ATD-5567 -- This has a fitting for our car, and you also need X feet of fuel hose and a hose splice -- cut one of the fuel lines in the kit (not the line that fits our car, the other one -- there is a hose that connects to the meter and to the hose that fits our car 0-- cut the hose that goes to the meter) and splice in a length of hose and clamps. This extends the fuel line so you can drive and see fuel pressure.
    Remove 3/2 directional valve -- making sure you know which way the fuel is going. The line form the fuel filter feeds the fuel rail. Splice in a length of feed line.

    (Note -- at this point is a good time to get up on a ladder and install the fuel pressure meter line, while there is no pressure in the system.)



    Cut the unnecessary bits off the 3/2 valve, leaving the mounting holes to use as a template for drilling the mounting plate on the new FPR.




    Here is the new FPR. Check the FPR for tightness of the vacuum line and the fuel pressure tap port. Mine was shipped with the vac line fitting loose.

    Note the mounting place has been bent to fit. It ships from the factor flatter than this. You want to drill a new hole in the mounting plate, and make one of the hols that's already there bigger to fit the mounting bolts for the 3/2 valve. Make the hols so the adjustment screw on the FPR is facing toward front, and get the FPR lined up as close as you can get to the frame rail while still leaving room for the vac reference port to have room for a vacuum elbow. What is shown here is the not-so-good hydraulic line that I used for the right angle turn that's needed. You need to find a better, more secure, smaller right angle piece to make this work better.




    Here is the new FPR in place -- front of car is to left of photo. Note space for vac reference line against fuel rail. Also note the back single bolt for the removed 3/2 valve. Before this photo, it should have been bend flat and hammered against the bottom of the car -- bolt pointed to ground. The clearance is needed.



    Side view, same thing:



    Another view, same step.



    A washer may be needed to get a good bite on the mounting bolt where the 3/2 valve was installed.



    Another view:



    The right angle fitting that was installed leaked on start-up. A twist of the wrench stopped it, but I don;t trust it long term. This fitting was too large, and it should be replaced with another approach. Edit, I'm not too sure about that bend he put in the mounting plate. It loks like it would fit fine if it were flatter.



    The 3/2 valve presumably needs to be installed to keep the electronic nannies silenced. Nobody anywhere could tell me what the 3/2 valve is for or what it does, but it appears to connect the return and feed lines under some unknown conditions. To make it fit, it has to be small. Now we cut the last extra bits off the 3/2 valve, making it as small as possible -- a cylinder with a cube on one end. Seal up all of the holes so nothing nests in it and no water gets in.



    The new home for the 3/2 valve. Note the back bolt from where it used to be mounted. Again, much earlier in the process, straighten that bracket out and hammer it flat against the bottom of the car. The 3/2 valve remains are zip-tied in.




    The plate that hides all of this under the car may need to be beaten into submission. My cover had enough gunk on it that nice shiny marks were left when we tried to install the cover -- easily showing where the install was not lining up. Solution -- Give it a good beating in just the right spots with a ball-peen hammer:




    Here's everything in place and plugged in.



    Tighten the lock nut on the FPR and start the car. Any leaks? Stop.

    My car had 30 PSI when it started, and ran rough. Adjust the Allen wrench clockwise?? to increase fuel pressure -- setting it at 44 PSI with vac line connected. Note -- the fuel pressure changes 1/2 psi when you lower the car -- the weight of the fuel in the hose = 1/2 PSI in my case. So if your hose is long like mine you might want to set it at 44.5 PSI, in case a half pound matters.

    The actual work time for the install was about 2 hours.
    Last edited by Johno; 02-05-2008 at 06:01 PM.
    Johno
    -- 2003 e46 M3
    -- 2018 e90 M5
    -- Warm memories of 99 M3 w/ Eurosport Twin Screw, 2007 335i, 1970 Cutlass, 1989 328is, 1990 328i, 2012 S4, 2018 S4


  2. #2
    Join Date
    Jul 2011
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    Guatemala
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    M3 e36 turbos
    I have a question, what did you did with the oem fpr???

  3. #3
    Join Date
    Apr 2005
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    Charlotte
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    e36 GT35 Turbo
    Quote Originally Posted by Alexlm View Post
    I have a question, what did you did with the oem fpr???
    3/2 Directional value IS THE FPR on this car, not on the fuel rail like some e36.
    Also see "running losses" to investigate the 3/2 value.

    OP, throwing any weird codes?

  4. #4
    Join Date
    Dec 2007
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    E36/7 E36/8x2 E46 F25
    The FPR is still the FPR, it's just mounted on the 3-2 valve block. The 3-2 valve's only function is controlling which route the fuel takes to get to the FPR.


    /.randy

  5. #5
    Join Date
    Jun 2005
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    New England
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    F90 M5; E36 M3 Turbo
    The stock OBD2 FPR just gets moved into the engine bay with the wiring harness plug connected so it can do its running loss thing even though no fuel is flowing through it and keep the ECU from throwing a code while the aftermarket FPR doe the work.

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