Fixed the stalling on '07 990

Discussion in 'Dakar champion (950/990)' started by wparsonjr@yahoo.com, Oct 27, 2007.

  1. wparsonjr@yahoo.com

    wparsonjr@yahoo.com n00b

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    Had a bad stalling problem since about 400miles in. Pull in the clutch, let off the throttle (read: shifting?!?) at about 60mph and it would stall every time. Take off from a stop and it would make me look like a nub by stalling or bogging out. Totally unacceptable and deadly to boot. At the first service Z-racing remaped the FI to stock and had the balls to charge me for it. This was in early September before the new map came out. Problem happened 5 min out of the shop so I won't be going back there. IMHO there is no excuse for that. So i tapped into the FI and cranked up the buttlerfly stop. Stock setting it was not even touching the throttle so I upped it a bit to just leave the butterfies open a tad. This increased my idle to 16500 and more or less fixed the stalling but it still ran kind of rough.

    I read on another thread that that 3-brothers fixed the issue by getting a KTM tech in to look at the bike so I figured I would let them run the recalls on it. They were prompt, 4-5 hours I got the bike back on a Saturday. When I got the bike back it ran like a dream bu the idle was still a tad high. I lowered it back down to the stock setting (not touching) and the stall/bog problem was back IN FORCE. So I figured that was the main issue. I went back in and adjusted it so it barely keeps the butterflys open at idle. Runs like a dream again. Idles at 1500, not perfect but the stalling was deadly. Also while I was in there my SAS blockoffs came in so I ripped the SAS off. That cured the engine brake popping and it seems to run even smoother.

    Anyway, if anyone is having stalling usues look at your throttle stop. If it is not touching the throttle it is my guess that the engine is choking at idle and killing your low end responce once you get off idle.

    Its a bitch to get to for a simple idle adjustment and take trial and error to get it right. You must remove the left tank to access the panel that covers the left side of the (clutch-side) of the airbox. It is easier to do if you take the top off the airbox and the filter but it is possible without doing so. I have got the procedure down to about 15min to make the adjustments. Why the hell there is no external adjustment is beyond me. My '06 vStrom had it so it can't be an emisions deal unless they are trying to skirt a test by choking off air tothe engine at idle.

    Good luck guys.
    #1
  2. cpmodem

    cpmodem Orange Caveman

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    Very interesting read. Thanks.
    #2
  3. GoNOW

    GoNOW Long timer

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    A 1500 idle is just fine. The engine is ultra light and it does not take much to make it stop spinning at low RPMs.
    #3
  4. NothingClever

    NothingClever Dirt Winger

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    Yep, BTDT. Definitely a dangerous condition which someday will lead to a lawsuit I think when a rider gets squashed. It sucks leaving a traffic stop and stalling a few feet ahead just as the cage behind you starts gaining momentum. Or worse is when you're making a left hand turn across traffic and the bike stalls just as you start to cross and there are oncoming cars.

    Another potential solution for the lean mapping is removal of the O2 sensor, the one that's in the exhaust rather than the one for intake.

    And yet another possibility is an extended tip spark plug which gives a more thorough burn because it sits lower in the swirl.

    KTMtwins wasted no time in putting a PowerCommander up for sale. It's too bad European manufacturers are having so much trouble getting the mapping right while trying to meet emissions standards for 2012.
    #4
  5. TOHC

    TOHC Adventurer

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    +1 on what WPARSONJR said.

    Sorry I didn't have a chance to follow up on my original post back in September about my 990 stalling... http://www.advrider.com/forums/showthread.php?t=265417&highlight=stalling ...until now.

    My bike went in the shop around mid-September. KTM NA actually emailed the tech with the then new FI map and recommended a few other software diagnostic procedures. Long story short, none of the recommendations worked. Raising the idle speed via software solved the problem for about 5 minutes, then the stallling returned. It took a bit of time going over the manual to locate the adjustment screw which prevent the electrical motor from closing the butterfly valve completely. Once adjusted the bike did not stall again.

    The bike now idles a bit faster and it sounds/smells like the choke is always partially on. Oh well, but the key is... its been 18,000 kms and haven't had a problem since. BTW, yes it took care of 4-5000rpm hesitation/bog problem as well.
    #5
  6. KTMSprocket

    KTMSprocket Skill Required Here

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    my '06 990 now has say 9000km done....recently i have had a couple of these shut-offs. curiously they were after the 7500km routine service....:kboom
    #6
  7. Venteuri

    Venteuri I don't give a shit

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    :scratch

    I don't know how I ended here, but it may be usefull for some people.
    #7
  8. CHRIS_D

    CHRIS_D Long timer

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    Interesting............ Has anyone tried adjusting the butterfly so it's not touching (which would raise the idle) as stated above then with the software adjust the idle back down to 1100 RPM. Or will you even be able to do this because of the slight opeining in the butterfly at off throttle.
    #8
  9. crashmaster

    crashmaster ow, my balls!

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    I havent tried that. I just took the secondaries completely off. No stalling in the last 1000 miles. That doesnt mean it wont come back though. So far so good.
    #9
  10. MOTOSOTO

    MOTOSOTO Light Fuse and Get Away!

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    ...I wonder if Z-Racing used my bike as the preliminary test bike for this. It's held residency there for ages...glad you got yours to work right.
    #10
  11. Hipster

    Hipster Long timer

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    Crashmaster,

    Besides no longer stalling, have you notice any other improvements without the secondary butterflies?

    #11
  12. crashmaster

    crashmaster ow, my balls!

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    I really cant say if it runs any differently or not. The difference, if any at all, would be very subtle. I know guys have removed the secondaries in an effort to get a smoother off idle throttle response, but I cant say that I notice a difference.

    Fuel mileage seems to be the same. What the hell is the purpose of those secondaries anyway? I asked the mechanic at the dealer and he said something about modulating intake air velocity. He put in a call to KTM, and they couldnt tell him exactly what purpose they serve.

    I'm not one to fck around with things that I dont understand (and this FI system is one of them) but so far the stalling has not returned. Like I said though, I have gone 1000+ miles before and not had a stall or low idle, then all of a sudden it would reappear. So I dont want to say that removing the secondaries is a fix for this problem, but it is looking promising. Only more miles will tell.
    #12
  13. marin ktm

    marin ktm Been here awhile

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    The opening post describes what the mechanic at the dealer said he did to my bike 7,000 miles ago. It works great now. It used to do the low idle thing half the time and stall once in a while. Not at all since the butterfly trick.
    #13
  14. crashmaster

    crashmaster ow, my balls!

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    Thats good to know. I wonder why the folks at KTM dont do this??? Could it just be a band aid fix that masks a more serious shortcoming?
    #14
  15. cpmodem

    cpmodem Orange Caveman

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    Sad to say. The FI on modern vehicles is all about meeting gov emissions standards. NOT engine performance. The new EU regs are even stricter than California/EPA (butt that may soon change).:vardy
    #15
  16. ridewestKTM

    ridewestKTM Long timer

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    If setting the throttle stop different has an effect perhaps positioning the TPS differently may help. This is a trick used on some cars. I have a 950 so I can't test the idea.
    #16
  17. cat

    cat Long timer

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    To modulate air intake velocity. To maintain air intake velocity when the throttle is whacked open. Some searching/google will get you more than enough explanation. It's not peculiar to the KTM 990.

    Given that ECU progam would not change, what factor/s changed to cause it to re-occur? The secondary butterflies were there all the time, and we can assume they didn't change their position. So what changed? Some or other sensors? Throttle bodies got out of synch perhaps? Isn't throttle synch related to this throttle adjustment business here?
    #17
  18. mookymoo

    mookymoo Mookish Mook

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    Its my vague understanding that the throttle balance/synch is achieved via those secondary butterflies. There is an airflow sensor in each & ECU keeps them balanced by controlling the air volume in each.
    #18
  19. cat

    cat Long timer

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    That's pretty much my vague understanding. :norton
    The sensors are MAP / Manifold Air Pressure and the ECU adjusts the intake velocity by moving the butterflies with the stepper motors - the "idle speed control motors".
    The throttle body synching done with manometers/whatever is done by adjusting the closed throttle stops / the butterflies "almost-closed" position screw adjuster so that the manifold pressure is the same on both intakes - with the MAP sensors removed.
    #19
  20. twodollardoug

    twodollardoug the calimesa kid

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    hey cat, is it really necessary to unplug the map sensors when syncing the tb's? because i have tested them plugged and unplugged with no change either way. what does unplugging them accomplish?
    #20