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  1. #1
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    Help me diagnose please

    An intermittent slow crank.


    Alright, so my car has been suffering from this for a few weeks now at random. I can hop in and immediately start the car without any wait and it cranks right away. Other times, I can wait with ignition on and it will crank slowly. Completely hit or miss. Seems to correlate with high humidity, the more humid the more often it takes a few more cranks to start.


    Car currently has P2a2d - fuel pressure low - stored but no CEL. Code actually came up after I was playing with INPA trying to test the fuel system. Never really found what I was looking for and wasn't there before this. I've gotten the occasional 2aaf but its been a while for that.


    So far i've tried datalogging it while it was starting and have gotten quick and slow cranks at different times. Under WOT on multiple different logs both fuel pumps show that they are having no problem keeping up with demand. See for self here.


    http://datazap.me/u/kingdlo/some-pul...zoom=1636-1780
    some pulls in here where you can see a run through the gears and pumps keeping up no problem


    http://datazap.me/u/kingdlo/starting...h?log=0&data=2
    Above log is some starting, and one where I launched the car, but thats not the issue here. You can clearly see pumps are putting out what the car requests if not more.


    Sometimes I get a nice exhaust smell coming from the back after a longish crank.


    I've narrowed it down to possibly leaking injectors where they are leaking after I shut the car off, but not sure how to really diagnose that. Or a possible bad LPFP sensor. I've read somewhere that when the sensor is bad it will request a constant output regardless of load instead of going up and down with request. HPFP goes up and down, LPFP does not. LPFP constantly requests about 72-73 or so no matter what.


    Thoughts/suggestions? Anyway I can accurately narrow it down?
    Last edited by kingdlo; 08-02-2014 at 06:04 AM.

  2. #2
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    Rep for anyone who helps him.

  3. #3
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    Anyone got a log of a lpfp showing the car requesting varying pressures???

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    How old is your car and are you on your original HPFP?
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  5. #5
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    Also, your datalog links aren't working for me for some reason.
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    it might sound crazy, but have you tested your battery or checked to make sure the cables are tight? What year is the car?
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    Click here to enlarge Originally Posted by froop Click here to enlarge
    How old is your car and are you on your original HPFP?
    Click here to enlarge Originally Posted by froop Click here to enlarge
    Also, your datalog links aren't working for me for some reason.
    My car is a 08 with 112xxx on it, according to my records pump and injector recall was performed at 46,xxx. I'll fix the datalog links when I get home but like I said logs show the pumps keeping up/exceeding demand.
    Click here to enlarge Originally Posted by rdeterman Click here to enlarge
    it might sound crazy, but have you tested your battery or checked to make sure the cables are tight? What year is the car?
    i checked the battery, while it is a White BMW battery I can't tell if it's newer or not. I checked the cables and they were tight. The battery indicator was also fully Green and not yellow in the slightest bit. Certainly seems like a fuel problem to me.

    Guys it certainly correlates with high heat/humidity. Yesterday temps were around 85 with 90+% humidity and it gave me trouble for the first crank after sitting for 5 hours. I have to check for leaking injectors still when I get a day but who knows when that could be. Still no solid CEL indicator.

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    Are you running any E85? Low pressure fuel pressures around 72 psi are normal. With 91/93 this will fluctuate very little but will stay close to 72. With E85 you will see more fluctuations. The low pressure side does not drop down to a low number like the HPFP pressures when cruising or no load. If the LPFP sensor was bad you would generally see it pegged at 87 with no fluctuation.
    E92 335is DCT

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    @kingdlo, have you had the battery cable recall performed?
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    You're probably gonna need a new HPFP again...
    Long cranks are a tell-tail sign, while driving will be perfectly fine for a long time until the pump really takes a nosedive.
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  13. #13
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    Had the same symptoms as my hpfp began to die. Lasted a while like David mentioned. Random long cranks, heavy fuel smell after long cranks. Logs gave me no heads up as I log regularly.
    E92 N54 3368lbs

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    My money would also be on the HPFP.
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    I have similar issues, with the "first gen" HPFP recall, 944 I think it was. I beleive they are only installing 170 pumps now. Leads me to beleive that the first gen was an improvement, but not a complete resolution.

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