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Thread: e83 cranks but won't start. Can't keep fuel pressure at the rail

  1. #1
    Join Date
    Jan 2019
    Location
    Seattle, WA
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    2
    My Cars
    2006 BMW X3

    e83 cranks but won't start. Can't keep fuel pressure at the rail

    I have a 2006 x3 e83 with m54. About a month ago it had issues starting when cold; cranks but doesn't start not a single fire. When starts, it runs very well with no issues. I checked fuel pump relay and swapped it with horn relay which is the same type. It didn't change anything. After couple of weeks it stopped starting. I checked fuel pressure at injectors rail and it was 0. Obviously fuel pump is dead and so I replaced fuel pump (using https://www.bimmerforums.com/forum/s...mp-Replacement), but still it doesn't start (it feels like one or two cylinders fire, but then it just cranks). I checked fuel pressure and it now jumps to about 50 psi when I turn ignition on, but then drops to 0 in about 2-3 seconds. It appears it can't maintain fuel pressure at 51 psi. I am wondering if fuel pump i just installed was defective. I got Powerco fuel pump from ebay. What else can this be? Fuel pressure regulator?

  2. #2
    Join Date
    Jan 2016
    Location
    Ca
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    5,502
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    2001 525it
    The fuel injection has a check valve to hold line pressure for a given period of time in the old cars when the check valve was on the end of the fuel pump. I have only used factory BMW fuel pumps, so I would think it's part of the fuel pump assy. Fuel pressure regulator is supposed to maintain line pressure when running, not allowing the pressure to go beyond the 45 psi range. If regulator had failed the pressure should be really high and when they fail you could have gas coming out of the vacuum line that goes to it.
    Last edited by jclausen; 01-12-2019 at 10:10 AM.

  3. #3
    Join Date
    Jan 2019
    Location
    Seattle, WA
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    2006 BMW X3
    Fuel pressure regulator on E83 is not controlled by vacuum like on E46 or others. My guess fuel pressure regulator has a spring pushing on a valve calibrated to open at certain pressure draining excess fuel back to the tank and preventing pressure to go beyond predefined level. Thus it is located inside fuel tank. So if this spring breaks or gets too weak, it won't be able to maintain fuel pressure and fuel pump will be just circulating fuel inside the tank. Now I am suspecting it is either check valve inside the pump, or fuel pressure regulator, or loose fuel line connection inside the tank.

    I don't know how to test check valve inside fuel pump and since checking fuel lines involves getting inside fuel tank, I ordered a new fuel filter with fuel pressure regulator and will be replacing it next weekend. I will disassemble old fuel pressure regulator to understand how it works and will update this thread. Any ideas how to test check valve inside fuel pump?

  4. #4
    Join Date
    Jan 2005
    Location
    Maui
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    459
    My Cars
    E90, E83, E46..Prius lol
    One simple thing to check, the ground strap on these cars get brittle and fails causing all sorts of strange problems. Check that, easy to fix. Get Napa ground strap. A good and cheap pre-preemptive fix for all E83.

    - - - Updated - - -

    One simple thing to check, the ground strap (under engine/trans area to chassis not battery ground) on these cars get brittle and fails causing all sorts of strange problems. Check that, easy to fix. Get Napa ground strap. A good and cheap pre-preemptive fix for all E83.

  5. #5
    Join Date
    Jan 2020
    Location
    Hartford
    Posts
    3
    My Cars
    2005 BMW X3
    Hello All, I am new to this site and new to owning a 2005 BMW X3 2.5L.
    I have a problem with my fuel system it seems. The SUV was running perfect, then I let it to a friend while I was away on personal business. When I returned, the SUV would not start. Cranks but no start. The person I let drive may have ran it too low or out of gas. I don't know because we had a falling out and don't speak. So I did a ton of research and indications are the fuel pump.
    I did read all of the codes. 12 of them, all related to "misfires" and related codes. I did spray starting fluid in the intake and it fired up then died when it ran out. I hear no sound coming from the pump under the back seat at start up.

    I have next to no tools or resources. But I did check fuses and relays...good. I swapped the horn relay with the fuel pump relay and nothing. (Horn) worked. I checked voltage at the connecter going to the pump and was weird. I turned the key and it showed voltage then went to 0. The other pins are getting 5 volts. Before I replace the pump, is there any other things I missed to check? No fuel pressure either. I cleared the codes hoping it might "reset" something.

    Please advise as I am starting a great new job very soon and don't have the money to pay for a shop or dealer. Thanks!

  6. #6
    Join Date
    Jan 2020
    Location
    Hartford
    Posts
    3
    My Cars
    2005 BMW X3
    Quick update. I applied 12v to the fuel pump directly and hear it running but not supper loud. Not sure if I have pressure get. No gage. Any way I can check with no tools?

  7. #7
    Join Date
    Jan 2020
    Location
    Hartford
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    3
    My Cars
    2005 BMW X3

    Reply, no start for my 2005 BMW X3 2.5L E83

    Hello and thank you for the advise. My current status is still a no start. I took the fuel pump out and cleaned everything. It runs with 12v applied. I reassembled everything and put a fuel pressure gauge at the fuel rail. Cranked engine and it went to 5p psi the feel a bit to 45psi. It starts with Starting fluid but seems the injectors are not getting the pulse input. I think the OBDII codes came from either running out of fuel or very low. I don't know the details since my ex friend is not giving me information on what happened when it died. Fuel is kind of greenish tint which I am not thrilled about but I did put a gallon of fresh fuel in it.

    Not sure if a new pump is necessary if injectors are not working on all 6 cylinders.

    I heard it could be an ingnition switch, a ECM, a totally clogged injector system. I am at a lost with minimal resources and funds.

    QUOTE=krautcars;30199152]One simple thing to check, the ground strap on these cars get brittle and fails causing all sorts of strange problems. Check that, easy to fix. Get Napa ground strap. A good and cheap pre-preemptive fix for all E83.

    - - - Updated - - -

    One simple thing to check, the ground strap (under engine/trans area to chassis not battery ground) on these cars get brittle and fails causing all sorts of strange problems. Check that, easy to fix. Get Napa ground strap. A good and cheap pre-preemptive fix for all E83.[/QUOTE]

  8. #8
    Join Date
    Feb 2013
    Location
    Oslo, Norway
    Posts
    10
    My Cars
    1999 BMW 523iat
    Quote Originally Posted by sergeyz View Post
    Fuel pressure regulator on E83 is not controlled by vacuum like on E46 or others. My guess fuel pressure regulator has a spring pushing on a valve calibrated to open at certain pressure draining excess fuel back to the tank and preventing pressure to go beyond predefined level. Thus it is located inside fuel tank. So if this spring breaks or gets too weak, it won't be able to maintain fuel pressure and fuel pump will be just circulating fuel inside the tank. Now I am suspecting it is either check valve inside the pump, or fuel pressure regulator, or loose fuel line connection inside the tank.

    I don't know how to test check valve inside fuel pump and since checking fuel lines involves getting inside fuel tank, I ordered a new fuel filter with fuel pressure regulator and will be replacing it next weekend. I will disassemble old fuel pressure regulator to understand how it works and will update this thread. Any ideas how to test check valve inside fuel pump?
    Hi @sergeyz Did this ever work for you?

  9. #9
    Join Date
    Jan 2011
    Location
    CDN
    Posts
    368
    My Cars
    08 X3
    Any update on this!

    I get intermittent fuel pressure build at the rail. Have to cycle the key on/off a few times to get the correct pressure. It eventually builds, but then also bleeds down. Not sure if the check valve in fuel pump is at fault. I did install a new filter/regulator last year.

  10. #10
    Join Date
    Mar 2019
    Location
    ATLANTA GA
    Posts
    270
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    456 X3s
    Quote Originally Posted by krautcars View Post
    One simple thing to check, the ground strap on these cars get brittle and fails causing all sorts of strange problems. Check that, easy to fix. Get Napa ground strap. A good and cheap pre-preemptive fix for all E83.

    - - - Updated - - -

    One simple thing to check, the ground strap (under engine/trans area to chassis not battery ground) on these cars get brittle and fails causing all sorts of strange problems. Check that, easy to fix. Get Napa ground strap. A good and cheap pre-preemptive fix for all E83.
    Good advice here

    Sent from my SM-J727T using Tapatalk

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