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Thread: 1998 R1100RT I pulled the cat code plug!

  1. #31
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    Ok I'm trying to catch up and understand the wideband thread.
    I see that rolling on the throttle abruptly will make Motronic leave closed loop and go to the richer open loop map.
    At that moment I can enjoy the slight increase in air throughput due to slightly (1/3) shorter valve lash.
    At cruise it burbles along, obviously lean. Won't idle very long, have to goose it every few seconds.

    Ok, pulling the cat code plug puts me in open loop all the time, and guess what it runs much better through the whole rev range.
    It idles.
    It never goes into closed loop though, so the cat converter gets happy only when decelerating.
    It's not easy being green.
    Perhaps a circuit that "pulls the plug" at idle, so it will idle at stoplights?
    Maybe charge a cap with the tach signal...

  2. #32
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    Quote Originally Posted by Roger 04 RT View Post
    On the subject of rechipping I'm a skeptic.

    If the rechipped bike continues to run Closed Loop with a stock O2 sensor, most of the fueling would remain at lambda=1.00. High rpms and wide throttle angles could change but most of the riding areas wouldn't.

    Rechipping could be used to advance or alter spark timing, unlikely to solve driveability problems like surging.

    The other problem I have with rechipping is there are no concrete statements about what they change, just that there is more power, but how?

    In the Wideband O2 Project, Wally G spotted that small throttle angles in first, second and third gear and rpms above 2500 resulted in lean Open Loop conditions. He also felt light surging in this area even with richened mixture, suggesting that this area is quite lean with stock fueling. Since this is an Open Loop area, you could rechip and richen it. No rechipper claims to change this area.
    This is like the 5th time I have read this and I finally understand.

    What's in the EEPROM ? - tables. I'm sure they didn't alter the code itself.
    What are the tables used for? - open loop.
    It doesn't really have a problem in open loop anyway.
    Their only claim is more power.
    So they just probably added 5% injector dwell to each table entry.
    Apparently pretty high in the band, right, where the little boxer is huffing and puffing pretty good.
    Getting anywhere from 0 to 5 HP gain somewhere.
    Not addressing low speed / closed loop at all.

  3. #33
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    Ok I swear this is my last post on this thread.
    And I'm sorry if I hijacked it.

    I installed a switch across 30 and 87 so I could switch between cat code plug installed and not installed.
    It is located where I can easily reach it while on the move.
    Results are predictable and already covered.

    Except: from seat-of-the-pants analysis the Motronic only reads the plug when the Motronic Relay comes on.
    It will not switch on the fly between the two settings "cat, O2 sensor" and "no cat, CO pot".
    You must pull over, kill the ignition, flip the switch, and restart.

    It does not appear to "need" a full reset (pulling fuse 5); however I am under the impression that while in Closed Loop the Motronic "makes notes" and corrections to the Open Loop tables, so you may not get a true unmodified map without pulling the fuse.

    Also if you are testing with Roger's or anyone else's contraptions using instrumentation, you'll want to follow their instructions as to resets.

    Bottom line is, switch not recommended, kind of a waste of time.

  4. #34
    Registered User roger 04 rt's Avatar
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    Quote Originally Posted by scott.lambert View Post
    Ok I swear this is my last post on this thread.
    And I'm sorry if I hijacked it.

    I installed a switch across 30 and 87 so I could switch between cat code plug installed and not installed.
    It is located where I can easily reach it while on the move.
    Results are predictable and already covered.

    Except: from seat-of-the-pants analysis the Motronic only reads the plug when the Motronic Relay comes on.
    It will not switch on the fly between the two settings "cat, O2 sensor" and "no cat, CO pot".
    You must pull over, kill the ignition, flip the switch, and restart.

    It does not appear to "need" a full reset (pulling fuse 5); however I am under the impression that while in Closed Loop the Motronic "makes notes" and corrections to the Open Loop tables, so you may not get a true unmodified map without pulling the fuse.

    Also if you are testing with Roger's or anyone else's contraptions using instrumentation, you'll want to follow their instructions as to resets.

    Bottom line is, switch not recommended, kind of a waste of time.
    So it sounds like your bike idles better if you start it with no plug, but does not idle better is you start with 87 connected to 30 but then open the switch.

  5. #35
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    Quote Originally Posted by Roger 04 RT View Post
    So it sounds like your bike idles better if you start it with no plug, but does not idle better is you start with 87 connected to 30 but then open the switch.
    The bad idle is too subtle to make a judgement by itself right after engine start. You have to ride it a little ways to detect the change.
    If you get up to a steady speed and hold the throttle steady with 87 grounded, it burbles and occassionally will miss altogether and give a slight lurch.
    Then when you shut down for a speed limit change it will rumble and pop.
    Once you get to a stop it will initially idle but within a few seconds will go so lean it will miss.
    If you catch it quick enough and goose it, it might recover. Might not.
    Starts again easily.
    Recall my abnormal valve lash is probably making this an extreme case of leanness.

    With 87 not grounded it will hum along with a steady throttle with still a slight burble but no lurching.
    Does not pop on the way into town. It decellerates strongly but still hums.
    Will idle at a stoplight indefinitely.

    I could detect no difference under medium / hard accelleration.

    I expected to be able to throw the switch at a steady speed and be able to detect the change immediately.
    Such has not been my experience. I found that I have to switch the ignition off and on again.

    Not instrumented, so I may be imagining all this. You might be able to prove it with a data capture.

    I thought that with 87 not grounded I might occassionally smell sulfur dioxide - so far no.
    Running no-ethanol 91 at the moment and I don't know what's in it.

  6. #36
    It's a way of life! oldnslow's Avatar
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    Another update on my 'plug pulled RT'. Did 700 miles yesterday and today. The bike ran really well. It had lots of smooth low end grunt, (which was nice in the pouring down rain while we rode about 50 miles of twisties. 59 degrees and heated grips on in July???!!!). The mileage was anywhere from 43 to 47 mpg; riding two up with side cases full of stuff. Before I started I cleaned the exhaust outlet to shiney bright clean. Still looks that way after the ride. No soot or such. Still haven't been able to get the exhaust emissions tested yet, so I don't know the CO content.

    The bike still surges a bit in 3rd gear at 3000-4000 rpm, but I can live with it.

    On a side note, I installed a set of ELF pegs. Those really help with the leg-knee-and butt pains!

    And this was my first ride in the rain with this bike. It really offers nice protection! I said earlier that I didn't think I could ever like this bike, but pulling the plug and installing the ELF pegs may make a believer out of me yet!

    Happy Independence Day to everyone!
    Mike Davis
    "Old n Slow" It's a way of life!
    1985 K100RT

    1998 R1100RT

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