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135i Low Pressue Issue

Discussion in 'Troubleshooting' started by [email protected], Nov 10, 2016.

  1. I got a 2008 135i with no fuel coming from the pump low pressure side...the low pressure pump works when I pulled it out and put power to it. something else is at fault and was told EKP module. Any other ideas as I go digging into this?

    May I also add previous owner wired two
    Helper pumps with surge tank in rear (removing all this shit, have all new PI going in and stage 3 pump). The wiring they did they spliced into the red and brown wire on the pump connector which is to the EKP as well.


    Attached Files:

  2. doublespaces

    doublespaces Administrator

    2009 E93 335i
    When did it stop working?
  3. Yea most likely the prevous owner shorted out the module, by not properly wiring into something he should have anyway haha. Also double check the filter side while your in there. Do you have an external pressure regulator?
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  4. Last week just slowly died out and left me stranded two miles from home
  5. It has a fuel lab FPR the gauge itself only pumps up barely 10 psi when trying to start car. I disconnected the fuel rail lines and there's zero fuel being pushed into there
  6. You can also disconnect the the feed line then open the door so the fuel system will prime itself and see if it's pushing any fuel out. Make sure you place that line on a bucket or you'll have a huge mess lol
  7. Where would you recommend opening it ?
  8. First check all applicable fuses. If all ok, check power using a volt meter at the pump connector. Also inspect the pins inside the connector as I've seen them melt before. If no power is there follow the wiring diagram to were the power comes from next. Which is the ekp module. Check voltage output there. If there isn't any coming out, check the voltage going in. Hopefully you have access to a wiring diagram, if not then your going to be either just throwing parts at it for hoping your on the correct wire when checking voltages.
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  9. It's beginning to become annoying but it ran and then slowly died, it died once before and came back on after an hour. I'm gonna test the EKP module
    Last edited: Nov 11, 2016
  10. *EKP module. power/ground/PTcan and wakeup wire go to it. I'm betting its been damaged.
  11. Just seen that, fixed the typo on that, thanks. I need to just rip and that apart and test the voltage as the car cranks. It has two wires that are jumped off of it from prior owner. So
    That probably definitely over worked the module itself.

    Jake (Motiv) also sent me a photo to check fuse F70 which is fuel pump related and fuse checks out to be okay with the power probe. I swapped it out anyways and same result. I attached the photo showing it next to F71

    Attached Files:

  12. Also was referring to this photo from ALLDATA

    Attached Files:

  13. Okay tested wire from EKP to pump connector and when cranking it's pushing 10 volts and under. I'm sure that's to low correct? And when car is in ignition it's 0. When I give it 12 volt pump comes on
  14. it is a clocked speed wire- pulse width modulated signal. 10 volts may be what your DVOM shows but is possibly just a low PWM signal
  15. What is approach in your opinion? I'm being told EKP is bad

  16. A scope would tell you if its sending the correct signal or not.
  17. Car is on now, EKP needed changing and it's running now. What I find odd though I seat the stage 3 pump good and all and did it three times already. Car smells of fumes inside and won't go over 75% tank of gas without over flowing through the filler neck.

    Possible fuel pump seal
  18. doublespaces

    doublespaces Administrator

    2009 E93 335i
    So replaced EKP and its good, glad to hear that.
  19. Yeah you guys were of great help, Just this stupid issue I'm now having with not being able to pass 75% tank when pumping and the smell of fumes. Something's not right -_-
  20. Snelson3003

    Snelson3003 Sergeant Vendor

    Ive heard that installing the pumps in the tank sometimes there is a line that gets pinched which offsets the overall housing and that causes the floater to be crooked. Makes the tank readings off by a margin.

    I would recheck the way the pump is positioned to see if the float is not leveling.