KTM 990 Idle Speed Control Stepper Motor Operation

Discussion in 'Dakar champion (950/990)' started by BillyD, Jul 6, 2010.

  1. rider911

    rider911 Shortcut Navigator

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    Are you sayin that the motor wont even turn over or just wont start?
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  2. Deviant666

    Deviant666 Been here awhile

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    A fellow here has logged (via a bt ecu sensors app) data that suggest that the idle stepper motor activates in various positions of throttle opening. However I've seen an Italian deactivating the stepper motor of a 990 SD (while fooling the ECU with a pair of resistors) and everything worked fine according to him...
    #22
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  3. Deviant666

    Deviant666 Been here awhile

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    It won't turn at all...you press the starter and the bike is as if it was in gear... (weird thing is that first cranking - without having cycle the ignition to off then on position, right after the completion of downloading the map - will start the bike, fooling you that the option of turning the idle speed motor off has actually gone through. Next thing you know it won't work if you have cycled through the ignition on/off once).
    #23
  4. Deviant666

    Deviant666 Been here awhile

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    Hahaha I just realised that the inmate has posted the refered logging above our posts (I've lost track of the threads I'm following, sorry).
    #24
  5. ktmjohn

    ktmjohn Been here awhile

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    I had same issue when disabling stepper motor. No crank over. Turn on stepper and it would start right up

    The idle issue is usually caused by TPS out of adjustment but with 60k miles I'd be looking for an air leak.

    Also, adjusting the main throttle plate stop screw along with the TPS is the solution to the the jerky throttle and other issues on the 990. I love my 990 after that change.
    #25
  6. josea1952

    josea1952 Been here awhile

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    I believe there is a YouTube video of this. I'll assume the ecu is looking for some signal from the stepper causing the no-start condition.
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  7. rider911

    rider911 Shortcut Navigator

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    I wonder if this is a glitch that TuneEcu introduces?
    I have not tried to physically disconnect the stepper myself but I will in the next few weeks. I find it weird that the engineers would design a system that shuts down the engine if a stepper motor has an open circuit condition.
    #27
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  8. Deviant666

    Deviant666 Been here awhile

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    Here's a youtube video of an Italian fooling the ecu via two resistors in the plug to avoid the shutting down. It seems to work and the engine idles fine.

    #28
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  9. Gordonktm

    Gordonktm Been here awhile

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    FYI This if from the OC Hall of Wisdom for anyone that wants to go that way found the TPS was the problem with my 990 after a lot of bad advice from the people that a paid to know

    Stepper Motor Equivalent:
    Bikyto: As you know, ktm only sells the whole throttle body for $1100-1300 depending of where you get it. Most people that have eliminated all the possible issues with sensors, tps, TB sync, pressure sensor...etc... And still have erratic idle issues, notability an idle that goes up and down or gets stuck at a particular rpm.... Are usually left with the need to replace the stepper motor. Well, here is the part that can replace the stepper motor on our throttle bodies for about $200 or so.

    Triumph 1050 Speed triple/1050 ST ----- part number T1241182
    #29
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  10. Salzig

    Salzig Long timer

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    Deviant, I guess you only disabled the stepper motor, and didn't disconnect it. Is it so? I think you should also disconnect it to prevent it from moving.
    The KTM ECU has a safety feature that disable the cranking when the main throttle is not shut: this could be the reason why your engine didn't start.
    #30
  11. Salzig

    Salzig Long timer

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    That's not the case.
    Per the manual, the error code 49 is idle stepper motor malfunction and it's not a shut off condition.
    #31
  12. guglemonster

    guglemonster Crivens!!! Supporter

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    #32
  13. DeepSea

    DeepSea electronically challenged

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    Salzig, exactly which sensors did you select to log the stepper data? I can't seem to find it in my list of sensors. The one I did find, was the idle engine speed read as RPM. The abbreviation is RPMRAL.

    Thanks,
    Steve
    #33
  14. Salzig

    Salzig Long timer

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    Here are the signals I selected:
    OSTEP - stepper reference
    ISCSTEP - stepper actual
    THAD - throttle voltage
    RPMMOT - engine rpm
    VBAT - battery voltage
    #34
  15. DeepSea

    DeepSea electronically challenged

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    Interesting. OSTEP and ISCSTEP are not options on mine. Are you using this program by Unityraptor? If not which one are you using?

    Thanks,
    Steve
    #35
  16. Salzig

    Salzig Long timer

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    Yes, that's the one I'm using. Weird...
    Wich year is your bike?
    Mine's a EU '07 model.
    #36
  17. DeepSea

    DeepSea electronically challenged

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    Mine is an 07' US. The closest one I can find is Idle Speed (RPMRAL). Best I can tell the data is what the engine idle is "shooting for" not what the actual engine RPM is. While running diagnostics here is (a snip) what I got.

    Example:
    (THAD) Throttle Position Voltage 1.53 V
    (ATP) Throttle Position 31.37%
    (TW) Coolant Temperature 76°C
    (RPMMOT) Engine Speed 6563 Rpm
    (RPMRAL) Idle Speed 1450 Rpm

    BTW, thanks for putting up that graph. It opened up a lot for me diagnosing my idle issue.

    Steve
    #37
  18. Salzig

    Salzig Long timer

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    AFAIK, US models are one year late then EU models, so yours should have the same ECU of EU '06 models (Sagem?) and not the Keihin like mine and later models.
    That should explain the missing values.
    #38
  19. jconly

    jconly Been here awhile

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    I've got a Keihin in my 07 US
    Don't forget, in the APP settings, you can choose between LC4 & LC8 engines.
    I believe its LC4 by default. Try switching that.
    #39
  20. DeepSea

    DeepSea electronically challenged

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    JC, I don't see a place to switch it. Where would it be located?
    #40