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Thread: Erratic Idle Upon Startup, In Park

  1. #1
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    Erratic Idle Upon Startup, In Park

    The car is a 2011 335i with xdrive. Not all the time, but fairly often, when we start the car up, the idle will jump and fall and jump and fall. This is while it is in Park, while you're getting your belt on and such. Seems to go away as soon as you put it into a gear.

    It's not a huge deal, although it can be embarrassing. The other day, though, we were driving and got a "Engine Malfunction: Power Reduced" message. That went away fairly quickly and there hasn't been any issue since, but I figure if something isn't working quite right, perhaps it's all related.

    Any thoughts? I greatly appreciate any input!

  2. #2
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    A diagnostic scan with a BMW scan tool/software, that can display BMW error codes,
    would be the quickest and most reliable path to a proper diagnosis.

    When access to a BMW tool is unavailable,
    an OBD2 scan at Autozone or similar is better than nothing,
    though generic codes can be misleading.

    Post back with results.

  3. #3
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    There is no check engine light on or any other warning messages, even when I go in to the system checkup tool on the nav computer, so I don't think an OBDII reader would find anything. But I could try. I actually own one.

    I was just hoping someone experienced this identical scenario and knew the cure. Wouldn't that be easy?!

  4. #4
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    Error codes are stored,
    if there was a specific system malfunction,
    it will be stored as an error or pending code,
    in one or more BMW modules.
    A generic OBD2 scan tool cannot communicate with,
    the multitude of BMW modules contained in your vehicle.

    There are multiple scenarios that can cause your symptoms,
    and I usually hate guessing, because you know the usual outcome when you or I ASS-U-ME!

  5. #5
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    Okay thanks, I guess I'll need to make an appointment.

  6. #6
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    Yes Dan,
    if you're not deep into DIY,
    maybe an appointment is the best path,
    as a 2011 3series is a rolling computer chassis,
    compared to your 1990 325is!

  7. #7
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    I’m a capable DIYer. In fact, I’m an automotive technician by trade. But I sure don’t have access to any BMW diagnostic equipment.

  8. #8
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    Well then, here are some options,
    concerning diagnostic tools,

    For a good BMW scan tool, I feel you have 3 options:

    • Foxwell nt520:http://www.foxwelltool.com/search/?q=NT520
    • Carly for BMW:http://www.mycarly.com/product/bmw-app/
    • INPA software for BMW: Do a search on bimmerforums

      I recommended them in no specific order,
      as selection is based more on preference.

      INPA is an excellent diagnostic tool,
      but is a proprietary BMW factory tool.
      So all available copies are technically bootleg versions.
      This requires a copy of the INPA software downloaded into a laptop computer,
      along with the correct cables for your particular model of BMW.
      I recommend this only for computer geeks, or the mostly computer savvy among us.

      For an affordable standalone unit, Foxwell nt510(nt520 Updated version) is the preferred unit, along with required cables.
      It can scan for BMW codes, among other things, as it can communicate with all BMW modules.

      Carly for BMW is an APP,
      and as such, requires a smartphone,
      along with a connection to the OBD2 port in your vehicle,
      supplied either by cable or wireless connection via Bluetooth dongle


    Update: Now the full version is $74/year on a recurring subscription
    Last edited by MIKYZZ4; 07-12-2018 at 05:29 PM. Reason: UPDATE

  9. #9
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    Btw, I never doubted your capabilities,
    until you threw in the towel,
    and decided to make an appointment.

    Welcome to the world of BMW,
    not actually difficult to diagnose,
    just different!

  10. #10
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    I wasn’t meaning to throw in the towel. I mistook your advice to basically mean “a dealer has to look at it.”

    Thanks for the recommendations! I’ll look into them.

  11. #11
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    I have ISTA, but I mostly use my Launch CRP123, which lacks some BMW bells and whistles but pulls manufacturer-specific codes from all makes of cars. Quick way to pull BMW hex codes from all modules.
    Are you gonna eat that?

  12. #12
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    When you state that " I mostly use my Launch CRP123, which lacks some BMW bells and whistles but pulls manufacturer-specific codes from all makes of cars.", begins my doubt that it can communicate with all BMW diagnostic computer modules.

  13. #13
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    It can't register a battery or code your vanity light to flash when you push a button on your remote. Wanna pull engine/transmission/SRS/ABS codes in 1/4 the time of ISTA? CRP's your guy.
    Are you gonna eat that?

  14. #14
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    Would you know, if you have experience with both,
    how the Launch CRP123 would compare to the Foxwell nt510 or the updated nt520 ?

  15. #15
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    Foxwell is manufacturer-specific. $160 for each make of car you want to work on. Hopefully it can register batteries and such. So can ISTA, which is free.
    The CRP has definitions for pretty much every manufacturer in the world.
    Are you gonna eat that?

  16. #16
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    Thanks,
    just wondering if it also had coding functions,
    in addition to simply displaying codes/definitions.

  17. #17
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    Nope. Just pulls & clears codes.
    Are you gonna eat that?

  18. #18
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    Okay, I realized a friend who owns a shop has a diagnostic tool that can communicate with the vehicle.

    Sounds like I'm in for a bit of a hurting.

    Here's what it said:
    2BEE High Pressure Fuel, Plausibility, Cold Start Pressure Too Low
    2C01 High Pressure Fuel, Plausibility Pressure Too Low

    We did a fuel pressure test via this diagnostic tool and it told us the following:
    Rail Pressure (High Pressure) 177psi
    Rail Pressure Nominal Value (Engine Running) 174psi
    Fuel Pressure (Low Pressure) 8.7psi (we think this value is not really accurate, we read something about not being able to read the low pressure this way, and it seems like that's way, way too low for the car to even be running)

    We wondered if the low pressure, in-tank pump was maybe on its way out, causing the high pressure pump to not work to its full potential, but in the end we figured it's probably just the HP pump. Thoughts? The cheapest HP fuel pump I found was here at eeuroparts: https://www.eeuroparts.com/Parts/493...t-13517616446/

    That is the correct one, yes? I did find ones on ebay for as little as $150, but I'm thinking they are to be avoided. Seems "too cheap to be good."

    I appreciate any input.

  19. #19
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  20. #20
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    Are you sure of that part #?
    Enter your VIN# here:https://www.realoem.com/bmw/enUS/select?vin=

  21. #21
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    Original part number is different, but they are interchangeable.

    Thanks!

  22. #22
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    I have the old one off and new one ready to go in when it arrives. Not a bad job. Time consuming, with a lot of things to unbolt and disconnect, but pretty straightforward.

  23. #23
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    So the car was acting up really badly, giving the reduced power message just about every time, and finally it wouldn’t stay running at all. That’s when I took it apart. New high pressure pump is on and all is well, or almost. The erratic idle speed upon startup that I initially described has not changed. And the only codes the computer was giving were related to the HP fuel pump (listed a few posts up). So with a new one on there, what else could it be? I’m guessing the issues were unrelated, but why was it not giving any other error codes if that’s the case?

  24. #24
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    Have your friend clear codes + reset adaptations.
    Allow it to idle from a cold start until engine reaches operating temperature.
    Adaptations should smooth out the idle by then.

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