1150 running rough under 3k RPM

Discussion in 'GS Boxers' started by alainmax, Nov 23, 2012.

  1. alainmax

    alainmax ca vaut le detour !!

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    Hello all,

    I cal the experts for an 1150 GS 2004 running rough at low RPMs then again some missing/skipping at high RPM . The higher RPM could be from me not going up there that often ...
    mid range seem fairly good

    here is what i ve done so far
    1) clean the air filter
    2) clean the spark plugs ( i have pics if you would like to see them...)
    3) disconnect the charcoal canister to see if it makes a difference : no
    4) check the seating of the throttle cables : looks fine to me
    5)drove with fuel cap open to see if vent issue : no difference
    6)disconnect the bottom plugs to see if it would run worse (thinking sticks) : no difference
    7) added techron to clean the injectors : no difference
    8) did a quick TB synch, but i do not have a twinmax, so used a home made manometer with water ( difference at idle is < 1.5 inch on the manometer). One BBS screw is IN a 1/4 turn more than the other ( L side if sitting on the bike)
    9) NEW fuel filter fitted
    10) new alternator belt ( unrelated to this issue), just got to 36K

    Maestro Jim Von baden told me to check for air leaks ( i do not see any but not easy to find i suppose) and check for throttle cable deflection at the throttle body ( i have > 1 mm) so they do not look too tight

    BTW, does the ABS module need to be removed in order to change the throttle cables??? they seem buried way under there !!


    What am i missing? thank you for any input and i appreciate you took the time to read this
    #1
  2. roger 04 rt

    roger 04 rt Long timer

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    You seem to have done a very thorough job. Here are some added possibilities:

    1) Stick Coils bad. Either or both. You can search this site for ways to test them. Just saw that you did this.
    2) HES sensor defective or out of adjustment.
    3) O2 sensor bad. Reset Motronic, ride. Disconnect O2 sensor under tank, reset, ride. compare.
    4) Your bike doesn't run well with your fuel at stock setting of the O2 sensor (14.7). Reset Motronic, ride compare performance before 1 bar on oil temp display to ride after fully warm. Let us know.

    RB
    #2
  3. pcwirepro

    pcwirepro Aspiring Adventurer

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    Pull the upper plug wires one at a time with the engine running and see if there is a noticeable difference. If the stick coil is good the engine wile stumble. If there is no difference then it's likely defective. You can swap stick coils from side to side to confirm.
    #3
  4. mudmullet

    mudmullet Been here awhile

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    Sounds like the problems I had before I replaced the stick coils.
    #4
  5. alainmax

    alainmax ca vaut le detour !!

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    Thank you
    Trying to locate the o2 sensor connector under the tank. Where is that thing located EXACTLY ??

    What does it looks like?

    I have the tank off now so that the first thing i wanna do then i ll recheck the sticks (however i already checked them a couple weeks ago). Will re test though
    #5
  6. roger 04 rt

    roger 04 rt Long timer

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    It is a two inch long, round connector 1/2 inch in diameter. It is on the right hand frame beside the alternator, usually tie wrapped to the frame. It has four wires. It is hard to get apart because it has two tabs that hold it together. Be careful.
    #6
  7. pcwirepro

    pcwirepro Aspiring Adventurer

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    You mention the lower (secondary) plugs in your OP and mention suspecting the sticks. The secondary plugs make little to no difference at idle. How did you test the sticks?
    #7
  8. alainmax

    alainmax ca vaut le detour !!

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    Yes i just unplugged the secondary sprk plug, on side at a time and rev'ed up to 3k rpm then let idle and see if it was skipping beats...

    You probably know a better way, feel free to enlighten this brain...

    Thanks Roger, i thought it was that. By now i already re mounted the tank and was hoping that the reset on fuse #5 would do it..

    It seem better but it could all be in my head right now. it raining hard to tinker outside ( already wet from the 1 mile...)
    #8
  9. roger 04 rt

    roger 04 rt Long timer

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    Sometime when it's cold, see how it runs before 1 bar on the temp display its getting some extra fuel then.
    #9
  10. alainmax

    alainmax ca vaut le detour !!

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    I checked that and it seemed a little worse which choke on
    #10
  11. pcwirepro

    pcwirepro Aspiring Adventurer

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    Whatchoo talkin bout Willis?
    #11
  12. alainmax

    alainmax ca vaut le detour !!

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    i meant idle accelerator.......sorry


    picky picky
    #12
  13. roger 04 rt

    roger 04 rt Long timer

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    Sorry, I meant start it from fully cold and immediately go for a ride and see if you have the rough running spots right around the time the first bar shows up on the temp display. At that time, the bike has warmed up enough to run well but it is before it enters Closed Loop, AND, there is a few percent of fuel enrichment. I've found right at that time most bikes with rough running issues that are caused by lean mixtures run better. If the problem is due to your HES OR Stick coils or something else it won't run any better.
    #13
  14. pcwirepro

    pcwirepro Aspiring Adventurer

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    See response #3. I still haven't heard the stick coils having been ruled out. The secondary (lower) plugs make no discernible difference at idle and in my case made next to no difference in performance. I made a canyon run without them connected and could hardly tell they were missing.
    #14
  15. alainmax

    alainmax ca vaut le detour !!

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    well Roger, it seem to run better in open loop and started running a little rougher when one first bar ( temp) came on....
    had little time today, will try to find some tomorrow to confirm...i did all this without the idle accelerator(:wink:) on...


    If indeed confirmed, i suppose i will take the tank off and disconnect the O2 sensor connection , reassemble and try again, right? if at that point it runs fine, do i just change the O2 sensor ( + module reset)?

    thanks Wirepro, I have not tried the plug dance yet

    Again thank you much for your help
    #15
  16. roger 04 rt

    roger 04 rt Long timer

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    Alainmax, Just before 1 bar it is Open Loop AND richer mixture. Often, the richness (only a few percent richer at that point) makes a big difference.

    What I think I'd do if I were you would be disconnect the O2 and add temporarily an AIR TEMP. Shifter like BoosterPlug or iice air. I have one you can borrow for testing. Does your fuel have ethanol in it? If so is it 10% like I get here in MA? Adding the air temp shift in open loop will keep the mixture a few percent richer. I don't recommend it as a long temp solution but it may give you a lot of insight.

    What we want to find out before you spend money on a new o2 sensor is how sensitive your bike is to its mixture.
    #16
  17. alainmax

    alainmax ca vaut le detour !!

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    thank you Roger,

    My mistake : i keep forgetting to include this info . : i have been running the booster plug for 3-4 years !!!
    :hide
    #17
  18. roger 04 rt

    roger 04 rt Long timer

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    Even though you have a BoosterPlug, if you follow my sequence it will have a different effect. With the O2 sensor disconnected and the Motronic reset, the BoosterPlug will always add 6% to your fuel. After a while of running closed loop the BP effect is greatly diminished

    However if you are running Ethanol fuel you need to connect the BoosterPlug in a different way for this test. That is because ethanol is 4% too lean. Normally the Motronic in closed loop corrects for this. To run the test open loop you need to add 4% for ethanol and 6% to get a richer mixture. The BP can be wired in series with the IAT for this test.

    Is your fuel with or without ethanol? Any chance you have ever run leaded fuel?
    #18
  19. longslowdistance

    longslowdistance Been here awhile

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    ?vacuum leak?
    #19
  20. alainmax

    alainmax ca vaut le detour !!

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    Yes the gas is up to 10%ethanol and no i have never run leaded gas in this bike.

    I have to take the tank off and see how i can run the BP in serie with the AIT (air intake temperature, right?) without cutting wires etc...otherwise, not sure how to proceed
    #20