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Thread: 1998 R1100RT I pulled the cat code plug!

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  1. #1
    It's a way of life! oldnslow's Avatar
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    1998 R1100RT I pulled the cat code plug!

    I pulled the yellow cat code plug today and went for a 1 hour ride. The bike is a keeper if I can make it run like this all the time! Surging gone, herky jery throttle gone, smooth idle, pulls smooth from down low in the rpm range, over all, a pleasant experience. Very rideable in town now!

    My bike is bone stock, 20000 miles.

    My question is, why did this make a difference. I have read all of the related posts I could find but the 'techno speak' goes way over my head.

    And what damage may this cause to my engine, if any.

    I discovered some threads about adding the Idle Regulating Valve after removing the CCP and disconnecting the oxygen sensor. That sounds intersting too. MPG doesn't concern me, because as it is now, the bike gets 0mpg because I don't like to ride it.

    I can tune a two stroke with screws, needles and jets as good as anybody, but this "open loop - closed loop - lambda- wide band -narrow band CO emissions" mumbo jumbo confuses me to no end.

    Sorry to bring up an 'oil thread' type of question, but I just need a plain speak summary of all the info I have gathered. Real world experinces would be helpful too.

    Thanks!
    Mike Davis
    "Old n Slow" It's a way of life!
    1985 K100RT

    1998 R1100RT

  2. #2
    Registered User roger 04 rt's Avatar
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    When you remove the Coding Plug on an R1100RT you have set up your motorcycle like it was originally designed to run without a catalytic converter. If you run premium, non-ethanol fuel you should get a good result. If you're satisfied with the idle you can skip the CO Pot (idle regulating valve). Red100Rt has described how he added a 1K pot at lower cost than the CO pot from BMW.

    This is a valid configuration which should be fine. It's possible that you could get some carbon accumulation in the exhaust but it doesn't seem to happen.

    It will be hard to understand what you've done without getting comfortable with the mambo-jumbo which is unfortunately the new plain-speak.

    RB

  3. #3
    It's a way of life! oldnslow's Avatar
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    Roger, should I also disconnect the 0-2 sensor? My idle is fine, smooth and strong at about 1100-1200rpm. (my eyes aren't what they used to be and that gauge has small numbers!)I am going to try and find a shop that will analyze the exhaust gas for me. Am I interested in idle and high rpm gasses, or only idle?
    Mike Davis
    "Old n Slow" It's a way of life!
    1985 K100RT

    1998 R1100RT

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    Registered User roger 04 rt's Avatar
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    Quote Originally Posted by oldnslow View Post
    Roger, should I also disconnect the 0-2 sensor? My idle is fine, smooth and strong at about 1100-1200rpm. (my eyes aren't what they used to be and that gauge has small numbers!)I am going to try and find a shop that will analyze the exhaust gas for me. Am I interested in idle and high rpm gasses, or only idle?
    My opinion is that you should leave the O2 sensor in the exhaust and connected. That way it will stay heated and not be damaged. With no Coding Plug, its signal will be ignored.

    If you wanted to remove it you would have to plug its fitting on the exhaust and remove your fuel tank to disconnect it. Not worth the effort IMO.

    The shop should only check carbon monoxide level at idle. Let us know the number (probably a few percent) and there's a table that will let us estimate the air fuel ratio at idle.

  5. #5
    It's a way of life! oldnslow's Avatar
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    Thanks Roger! What about damaging the catalytic converter? Am I risking this with the plug pulled? I don't mind if I ruin the converter as long it doesn't damage the rest of the motor. Thanks for all your help! You may have saved this bike from being banished to the back of the garage!
    Mike Davis
    "Old n Slow" It's a way of life!
    1985 K100RT

    1998 R1100RT

  6. #6
    Registered User roger 04 rt's Avatar
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    Quote Originally Posted by oldnslow View Post
    Thanks Roger! What about damaging the catalytic converter? Am I risking this with the plug pulled? I don't mind if I ruin the converter as long it doesn't damage the rest of the motor. Thanks for all your help! You may have saved this bike from being banished to the back of the garage!
    I don't think you'll hurt the cat converter. With a richer mixture, although there are unburned hydrocarbons in the exhaust, there's no oxygen left to burn them so the cat won't get hotter than usual.

    At some level of richness there is the possibility of carbon accumulation but I don't think you're there. Get the idle CO number and you'll know how rich its running at idle.

    Power Commanders and Techlusions can add a lot of fuel than pulling the Coding Plug and I haven't seen any posts related to carbon accumulation from using them.

    Many R1100 owners have pulled the Coding Plugs.

    I think you should do a google search though if you're concerned.

  7. #7
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    Quote Originally Posted by oldnslow View Post
    I can tune a two stroke with screws, needles and jets as good as anybody, but this "open loop - closed loop - lambda- wide band -narrow band CO emissions" mumbo jumbo confuses me to no end.
    Yeah when you understand how simple the new systems are you are going to be quite impressed with yourself, trust me.
    Nowhere near as complex as a high-performance two-stroke.
    There's still a lot of fascination with changing exhaust systems for example but it makes precious little difference to the fuel-injected boxer.
    With a two stroke you have to tune the whole system all at once, makes it hard to experiment.

  8. #8
    It's a way of life! oldnslow's Avatar
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    MPG update

    After 350 miles of twisties and some 70+mph highway runs, riding two up, my mpg was at 46 mpg. Thats as good or a touch better than it was with the cat code plug inserted! Im a happy boy now!
    Mike Davis
    "Old n Slow" It's a way of life!
    1985 K100RT

    1998 R1100RT

  9. #9
    Registered User roger 04 rt's Avatar
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    I think you'll be satisfied as long as you run premium fuel, NO ethanol.

    If you get fuel that's 10% ethanol your bike will run fairly lean and may exhibit the surging again. With no Closed Loop program running the Motronic won't be able to adapt to the leaner fuel.

    When you get a chance I'd love to hear what your tailpipe CO Is at warmed up idle.

    RB

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    Ok, time-before-last time out with Rod we stopped and filled up with no-ethanol 91.
    My MPG went from 45-ish to 50.
    Theory: more energy in the non-ethanol fuel, you don't have the throttle open as far.

    Yesterday I pulled the yellow code plug, filled up with no-ethanol 91, rode most of the day, refilled at the same station.
    43MPG.

    It does run better. But...

    From the wiring diagram this looks like a simple 3-bit code, zero through 7.
    Pulling the plug must make the code zero.

    Any documentation on what the other 6 codes do?

  11. #11
    Registered User roger 04 rt's Avatar
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    Scott, There is more energy, though not a 10% difference.

    The stoichiometric ratio of E10 is 4% lower, meaning it takes 4% more fuel to hit the Oxygen sensors target of lambda=1. So when you use non-ethanol, the Motronic actually produces injector pulses that are 4% shorter induration than when you burn E10.

    Any difference beyond 4% is something other than the fuel.

    See this for coding plugs: http://bmwsporttouring.com/ubbthread...43#Post760243/

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