Throttle hesitation R1100GS

Discussion in 'GS Boxers' started by NW Cascade Rider, Oct 7, 2012.

  1. Murkidi

    Murkidi R1100GS adict

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    hi, thats a interesting tecnique for cleanning the inyectors could you explain it better or PM the procedure THANKS :ear:ear

    manuel


    #21
  2. NW Cascade Rider

    NW Cascade Rider Dual Sport

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    So its been a while. And its mainly been because of the massive frustration I have had with working on the bike. I Got the coil and the plug wires and the new plugs and installed them on the bike. NO difference, or at least not much. I bought a brand new compression gauge and did a compression check cold on the engine. The right jug (which is the problem side) had higher compression that the left jug. About 175 psi right, the left jug wasn't far behind at about 170 psi.

    That all being said. If the compression is up, that rules out any major valve adjustment issue and definitely not piston rings. Its getting fuel and spark. at least in some fashion, unfortunately my eyes aren't tuned to see when the injector opens and the spark fires exactly on time with the engine. SO to me that leaves only three possible problems. The Motronic control unit. The Throttle position sensor. Or the part I ordered which I think it is, The Hall Effect Sensor. And I base that conclusion on this reference. http://users.rcn.com/dehager/service/oilhead_hall_sensors.pdf

    The symptoms as described match what my bike is doing decently.

    Hall Effects Sensor Failure Symptoms:
    1 Difficulty starting ( hard to start if at all )
    2 sudden engine shutdown ( does this all the time )
    3 No Spark ( hard to say, there is at least some spark )
    4 No fuel pressure ( non issue )
    5 Bouncing tack ( non issue )
    6 Engine restart after cool ( some times, goes back to symptom 1 )

    I ordered just the sensor's, not the entire assembly because its close to $270. The sensors by them selves were only $130 with shipping, and are the correct and updated part number. So again I have to wait for the parts to come in and then install them. I am hoping for the best because I am getting some what tired of working on this bike and not having any results. At least its paid for... Any thoughts and input, as always, is appreciated!
    #22
  3. roger 04 rt

    roger 04 rt Long timer

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    Have you checked the fuel flowing at idle, in the return line from the fuel distributor back to the tank?

    I know it's a little hard to set up if you don't have QDs but you should expect 2 liters per minute. If you get about that amount then you know your pump, hoses, fuel pump screen, filter and fuel pressure regulator are working correctly.

    It's basically a no-cost test.
    #23
  4. NW Cascade Rider

    NW Cascade Rider Dual Sport

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    Flow is fine. New fuel pump, new fuel filter, new fuel rail, cleaned both the fuel injectors and throttle bodies. Fuel flow is what I thought at first and is also where I started my troubleshooting.
    #24
  5. Gezerbike

    Gezerbike Hey Rocky...........

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    How did the bike run before you made the exhaust and air intake modifications ?
    #25
  6. LBourque

    LBourque G/S nut

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    Assumed you have adjusted the throttle cables.
    #26
  7. NW Cascade Rider

    NW Cascade Rider Dual Sport

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    The bike ran fine before and after. If anything is backfired a bit when it was stock. I had bought the bike with the K&N air filter already on the bike, and that was years ago. I got about 2 or 3 months of riding in after I installed the new exhaust. I don't think the exhaust is my issue. And yes the throttle cables are in adjustment. I have gotten good at doing that with the amount of time I have been in and out of that area.
    #27
  8. roger 04 rt

    roger 04 rt Long timer

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    And you're saying that you know the pressure is accurate and the return volume is in spec? I couldn't see the cracks (plural) that were in my in tank hoses. Even after I removed the hoses I needed to cut them open to find the leaks. If all that is good, that's what was asking. Seems like you have a tough problem. I hope the HES helps.
    #28
  9. NW Cascade Rider

    NW Cascade Rider Dual Sport

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    Ultimately I am just going to take the filter out of the tank and mount it externally. Its to much of a pain to get at from the inside. And the tank breather lines need to be replaced anyway so I am just going to replace all the hoses while I'm in the tank.
    #29
  10. NW Cascade Rider

    NW Cascade Rider Dual Sport

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    So I replaced the HES. That was a fun little project, that yielded no success. It took me about 5 min of cranking the bike before it even fired, and when it did, there was all kinds of smoke coming out the back for about the first minute. Then that cleared up, but the bike didn't want to idle well at all. So I shut it down and ended up disconnecting the TPS, and started back up. Lowe and behold it idles fine. Not the best throttle response ever (to be expected) but it idled consistently and without assistance.

    So, now that I have replaced everything aside from the TPS and the Motronic control unit, I think I have maybe a bad or poorly functioning fuel delivery system, and a bad TPS. So again this weekend when everything shows up, I'm going to mount an external fuel filter, change the fuel lines, and swap the TPS. Wish me luck....
    #30
  11. roger 04 rt

    roger 04 rt Long timer

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    Good luck with this. I might have mentioned it but if there is a way you can measure the volume of fuel returning to the tank when the bike is idling, you can get a good idea of the whole system. There should be about 2 liters returning to the tank per minute. Other than you're relying on the fact that the fuel pressure regulator is working, the return volume test is checking the pump, filter and in-tank hose integrity.
    #31
  12. NW Cascade Rider

    NW Cascade Rider Dual Sport

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    Its a fuel problem. It has to be. I Installed the new TPS. It seemed to help a little. But it was still having issues starting. I so grabbed some starting fluid from my beetle and gave it a squirt. sure enough it roared to life without hesitation and ran great until the fluid mist ran out. So then I thought if it was a fuel restriction problem I could disconnect the return line only to help build fuel rail pressure. It didn't help, and listening to the fuel pump, it didn't seem to be like it was building any additional pressure. So I went to the auto parts store and bought 6 ft of fuel line and 6 ft of smaller line for the in tank breather line as well as an external mount fuel filter. So tonight I am going to hook all of this up and hope it fixes it. I WANT MY BIKE BACK!!!!!!!!
    #32
  13. mouthfulloflake

    mouthfulloflake Not afraid

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    Did you get the proper submersible high pressure fuel line for the lines in side the tank? ( the proper stuff is 5/16" SAE J30R10) its about $18 per foot i think.

    and what will you do about the "U" shaped peice? its $35 from BMW, you cant bend a tight enough radius with the submersible fuel line.
    #33
  14. RAL88

    RAL88 Marineboy

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    As was mentioned earlier just mount the fuel filter externally. I replaced my fuel filter in the tank and then 500 miles later got a bad tank of gas and had to replace it again. That's when I moved it to the outside and it made things so much easier. You can easily bend the fuel line that replaces the filter.
    #34
  15. NW Cascade Rider

    NW Cascade Rider Dual Sport

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    Yeah I bought a large filter to mount externally. I also got some brass fittings that I am going to use for the 180 deg angle I'm doing all this fun stuff tomorrow. Ill check back when I got it done.
    #35
  16. roger 04 rt

    roger 04 rt Long timer

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    It will be interesting to hear about the condition of the hoses that are in the tank. I ended up having to dissect mine after removal to find the cracks. I decided to leave everything in the tank.
    #36
  17. grub

    grub Requires Supervision

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    :lurk
    #37
  18. PlatinumEagle

    PlatinumEagle n00b

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    I know this is an old thread, but I'd love to know the final resolution on this... even if you ended up putting the bike out to pasture, as I'm having the exact same symptoms.
    #38