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Thread: E90 N51 won't start 328xi (not fuel pump?)

  1. #1
    Join Date
    Jan 2014
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    Antioch, Ca. USA
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    2007 328xi BMW

    E90 N51 won't start 328xi (not fuel pump?)

    Hi:
    I've been working on my car for six weeks now with still no success. We were driving with no prior problems and the engine suddenly died. It cranks but won't start. There was voltage at the fuel pump but I couldn't hear it run, so I changed the fuel pump, car still won't start, and there is still voltage at the pump and you can hear the pump hum. Any ideas?

    Thank you for any help!

    Agalindo

  2. #2
    Join Date
    Jan 2012
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    Your car does have 2 fuel pumps. One to move fuel from one side of the saddle shaped tank to the other side, and the normal fuel pump to move fuel to the engine compartment. Do you have fuel pressure in the engine compartment?

  3. #3
    Join Date
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    07 e91
    how much voltage do you have at the pump?...do you have fuel at the engine?.....how much pressure is there?....

    JP

  4. #4
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    You don't have two fuel pumps, fuel is drawn from one side of the tank to the other by a siphoning effect. What diagnosis have you done beyond the fuel system? Any fault codes?

  5. #5
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    Quote Originally Posted by meangreen94z View Post
    You don't have two fuel pumps, fuel is drawn from one side of the tank to the other by a siphoning effect. What diagnosis have you done beyond the fuel system? Any fault codes?
    Bentley manual show 2 fuel pumps. Check it out.

  6. #6
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    I work on these cars for a living, there is only one electric in tank fuel pump, on the passenger side. On the drivers side is a sending unit, fuel filter, and pickup for fuel. Some manuals refer to the siphon jet as a "siphon jet pump". The N54,N55, and M57tu have mechanical high pressure pumps mounted to the engine, but only one electric intank pump.

  7. #7
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    Quote Originally Posted by meangreen94z View Post
    I work on these cars for a living, there is only one electric in tank fuel pump, on the passenger side. On the drivers side is a sending unit, fuel filter, and pickup for fuel. Some manuals refer to the siphon jet as a "siphon jet pump". The N54,N55, and M57tu have mechanical high pressure pumps mounted to the engine, but only one electric intank pump.
    Do the fuel filters every get clogged?

    JP

  8. #8
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    Ive yet to see one clogged. They are "lifetime" per BMW like coolant and transmission fluid. Which translates to we don't want to cover it under our standard or extended maintenance plans. The filter comes with the sending unit and siphon jet hoses that run over the saddle to the fuel pump. You have to disconnect them from the fuel pump side and pull them through to the passenger side and out the access hole. I've replaced them before when cleaning out fuel tanks for contaminated fuel.

  9. #9
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    Quote Originally Posted by meangreen94z View Post
    Ive yet to see one clogged. They are "lifetime" per BMW like coolant and transmission fluid. Which translates to we don't want to cover it under our standard or extended maintenance plans. The filter comes with the sending unit and siphon jet hoses that run over the saddle to the fuel pump. You have to disconnect them from the fuel pump side and pull them through to the passenger side and out the access hole. I've replaced them before when cleaning out fuel tanks for contaminated fuel.
    Not to be a dick, but are you sure you work on these cars for a living?

    It's an N51, SULEV. It has no access port other then the fuel pump opening, it's a sealed gas tank. His problem is almost positively a popped off fuel line at the fuel pressure regulator inside the tank, we do these all the time...

    OP, pull off the access cover for the fuel pump and use a flashlight to look inside the tank. When you look down, look to the side closest to the passenger door and you will see a round white fuel pressure regulator with 1 hose coming off of it. There will be a rubber hose and clamp that will likely not be connected at all. That will be your problem. You need a complete gas tank.

  10. #10
    Join Date
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    You're right, sorry I forgot it was an N51. They never sold SULEVs in Texas and only on occasion do I work on them, so I a drew a blank on that. He is correct you can only access the passenger side.
    Last edited by meangreen94z; 01-16-2014 at 09:42 AM.

  11. #11
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    Longmont, CO
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    2010 328xi N51
    Another thread without a conclusion...what was the outcome?

  12. #12
    Join Date
    Oct 2015
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    Oklahoma
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    E90N51 E39M5 E46xi

    Thread revival

    I am having this same issue, car died suddenly while driving. Zero pressure at the rail. 10 V at the pump while cranking. When I power the pump I can hear a faint whine (seat out access lid still on). I'm thinking the fuel line popped off the fpr. Cornerspeeed are you saying the entire fuel tank has to be replaced?? The line can't simply be reconnected?
    If true then apparently BMW no longer gives a $hi+ about ease of repair. I have never encountered anything so fn stupid on my e46 or e39.
    BTW the e90 is 328i xdrive sedan N51.
    Last edited by xrviz; 02-10-2016 at 01:08 PM.

  13. #13
    Join Date
    Jun 2018
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    Virginia
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    2009 E90SULEVN51 Xdrive

    Direct Power

    Quote Originally Posted by xrviz View Post
    I am having this same issue, car died suddenly while driving. Zero pressure at the rail. 10 V at the pump while cranking. When I power the pump I can hear a faint whine (seat out access lid still on). I'm thinking the fuel line popped off the fpr. Cornerspeeed are you saying the entire fuel tank has to be replaced?? The line can't simply be reconnected?
    If true then apparently BMW no longer gives a $hi+ about ease of repair. I have never encountered anything so fn stupid on my e46 or e39.
    BTW the e90 is 328i xdrive sedan N51.
    Apply power and ground straight from the battery with a 30 Amp Fuse and a switch in between. If the car starts, your EKPS (Fuel Pump Controller) is faulty and sending garbage power out to power the pump or you have gone into limp mode and the ECU senses some fault that it is going to send signal to EKPS to cut power to the pump. My pump stays powered directly. I have even seen the American Muscle cars have up to 17 volts applied directly to a pump with a fuel pump booster. The EKPS has two connectors. Only the power and ground cable needs to be removed to hack out the fault.

    Also, if you have a non BMW battery installed it will also cause this problem.

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