Fine tuning the BMW fuel control for better driveability and performance

Discussion in 'GS Boxers' started by mouthfulloflake, Feb 7, 2014.

  1. mouthfulloflake

    mouthfulloflake Not afraid

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    Let us come together, and share what we have learned and experienced about these bikes to help one another.


    My 1995 R1100gs, motronic 2.2

    100K+ miles, stock exhaust and intake

    pings with rapid throttle application, gets terrible fuel economy ( 35-37 mpg)
    and surges.

    I have tried a few different CCP settings, a myriad of TPS voltages from .300-.480 at idle
    tried advancing and retarding the timing

    valves were done by me, pretty close perhaps not as perfect as they could be.
    TB synch done about once a month. ( just because I hate the pinging and surge, struggling to find a solution)
    ive tried lots of things, but , what are your honest experiences and findings with tuning adjustments, and aftermarket add on devices?
    #1
  2. HighTechCoonass

    HighTechCoonass Living the Dream....

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    Since you have tried restive tuning.... What ya think of Lennie's sprockets?
    http://www.boxer-performance.com/

    Here are two good tuning threads I have read on tuning up the older oil heads...

    http://www.advrider.com/forums/showthread.php?t=749080

    http://www.advrider.com/forums/showthread.php?t=935445




    #2
  3. k1w1t1m

    k1w1t1m Kiwi

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    I'm looking forward to the responses.
    #3
  4. EScott

    EScott Adventurer

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    When I still had my '99 1100S the only real solution I found to those issues was to install one of the aftermarket chips in the Motronic.. Relatively simple process (plug and play) but made a significant improvement.. Not sure how available those would be now, but there must still be some out there somewhere. With 20/20 hindsight I probably should have kept that bike....
    #4
  5. mouthfulloflake

    mouthfulloflake Not afraid

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    That is interesting EScott,

    I was just reading about some of that sort of stuff.

    That makes me wonder about a few things.

    1) the motronic already has a pretty good ignition curve ( lots if ignition advance at low throttle openings) so much so that many folks ( like me) have pinging with low octane fuel and warm temperatures. So that likely would not be an area that I would change much.

    2) the common opinion is that the stock configuration is simply lean much of the time, at cruise, at acceleration etc. So it might be a good thing to hard code more fuel into some of those areas, but I wonder if the O2 sensor is used with any of the aftermarket chips? Other wise the cruise AFR might still be too lean if a reprogrammed chip still relied on the O2 sensor for steady state cruising.

    3) there is a ton of information out about tuning the Motronic ECms for various automobiles, I wonder how much of that information would translate to the bikes, this is mainly a hardware question, I would not expect the software to be very similar at all.
    #5
  6. mouthfulloflake

    mouthfulloflake Not afraid

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    Additional info for my particular bike

    1995 r1100gs

    with stock rose pink CCP
    it has good bottom end at low RPMS
    it surges
    it pings easily when the throttle is rapidly opened at lower rpms
    top end seems a bit 'soft'



    with the 'step toe" mod CCP setting which I believe simply ignores the O2 sensor and runs a bit richer

    the bottom is a bit more 'blubbery' not as sharp
    it does not surge
    it pings easily when the throttle is rapidly opened at lower RPMS
    top end seems a touch stronger


    My fuel economy is pretty bad in either configuration, I am replacing the O2 sensor right now, maybe if it warms up I can test ride and see if that changed anything
    #6
  7. terryckdbf

    terryckdbf Bumbling BackRoad Riders™

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    Well, if you wanted to change the EPROM I would suggest Rhinewest in Texas.

    http://www.rhinewestperformance.com/r1100gs.html

    One of the guys I ride with has an 1150RS with the Rhinewest chip and a Remus exhaust, bike runs really well. They are not cheap at $350 and they may be out of the motorcycle end of the chipping to concentrate on autos. You will need to call them to check on that if that is the way you wish to go. To add fuel there is always the PC, Techlusion, Bazzaz, and others. Those will affect fueling after the ECU of course.

    You could also go wideband with the Innovate LC-2, AEM, Zeitronix and many others. These are much less expensive than the Power Commander, have the ability to set the A/F R where you want it with a Laptop and more importantly work with the ECU not against it. Be advised, there is some wiring involved with these, not close to a plug and play item.

    Another option is the AF-XIED. It is much less expensive than the PC, it is adjustable to the A/F R you want, it works with the ECU, not against it. I am not sure if the 1100 is plug and play or not, it may require a couple of wires to be spliced, the 1150 and 1200 are plug and play. On another forum there was a guy with pinging issues, threw everything he could at it, solved it with the AF-XIED devices. That was not an 1100 like yours, I have no idea if the pinging is related.

    You have some options, I have no idea what is best for your situation. Hopefully the new O2 did the trick, hopefully it is not Carbon build up.

    Ride safely

    Terry
    #7
  8. mouthfulloflake

    mouthfulloflake Not afraid

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    Good input Terry!

    thank you.

    The intent of this thread was not only to address my own bike, but hopefully to have some discussions about varying solutions and methods of "tuning" with as little bias as possible.


    Id like to know if the rhinewest chip ignores the O2 sensor, or if it sets a richer target or what, that might be good to know.

    I need to suck some seafoam, or techron thru the vac nipple to try and clean some of the carbon, i KNOW it is carboned up pretty good.

    I hope to get a test ride tomorrow, and I will start from zero basically, from scratch.
    #8
  9. terryckdbf

    terryckdbf Bumbling BackRoad Riders™

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    The Rhinewest Chip is a complete new EPROM, it has 2 maps including timing differences, one for stock, one for aftermarket exhaust.

    I heard they no longer did bikes but that may not be true, give them a shout Monday, they will talk to you.

    Is it possible to see carbon build up through the sparkplug hole?

    Terry
    #9
  10. mouthfulloflake

    mouthfulloflake Not afraid

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    I noticed quite a bit when I had the cylinders off.

    http://www.advrider.com/forums/showthread.php?t=559098

    that brings up a couple of things.

    yeah carbon might be causing the pinging.

    But, I used the 3 layer gaskets instead of the 4 layer, so I effectively reduced the 'squish' area
    and increased compression albeit very slightly, both likely contribute to the pinging that I am fighting.
    #10
  11. Gruesome

    Gruesome Alter Heizer

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    Now it is a bit late, but cleaning the crud off the valves and piston should come before fiddling with the fueling, IMHO.
    #11
  12. roger 04 rt

    roger 04 rt Long timer

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    My take on the 1100 is fairly simple: unlike the 1150 and 1200 it has an open loop mode. This means for an 1100GS you've got two basic choices.

    Open Loop
    1) run a 30-87a coding plug, and install a CO pot. Then adjust warm, idle CO to 2.5-3%. If your gas has ethanol in it, add an HTCA air temp shifter set on -20C and make sure to put the probe into the intake manifold, not just any old place. Your bike should run great.

    Closed Loop
    2) run a Pink Coding Plug and AF-XIED on setting 8; you will need to splice the Universal Cable to the O2 sensor. Your bike will run great.

    Fixes
    A) pinging: Clean Up all the carbon.
    B) mileage: Make sure your O2 sensor functions and reset your ecu.
    #12
  13. vintagerider

    vintagerider Long timer

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    44-48 mpg is typical for the 1100 GS with stock config. Suggest that you remove the tb's clean and put in new bushings, shafts as its probably sucking air. I used an aluminum polish inside mine to clean it up. Hopefully no one has messed with the throttle angle stop screw. Replace the rubber doughnut that surrounds the injector and the rubber intake manifolds as well. It's kinda difficult to sync those tb's which use the single throttle cable but it is possible. Replace the cable. Make sure the air induction isn't leaking.

    Go through the entire fuel prep and delivery system. You may be due for a new pump, and refreshed injectors. You'd be amazed at how fast a stock ff will plug. You can up the pressure by switching the Bosch regulator to a 3.5 from another BMW model. That's been done a lot. Check out Hasenwerk's threads if you want to try an adjustable one. Still, I've have had almost -0- hesitation on my stock 96's and very satisfying throttle compared to any stock 1150. I know of several 95's that run like a top.

    After you've refreshed the fuel prep and delivery you can convert over to non-U.S. spec by installing the factory CO potentiometer (aka "idle valve"). There is a spot for it in your harness. You can then unplug the O2 sensor (have you every changed that?) or keep it. That's the advantage in the 1100 vs the 1150 w/ Mo 2.4. You can get quite a bit of enrichment with just the CO pot.

    It' s equally important to re-seal the exhaust joints.

    You should see a vast improvement with just refreshing in stock config. If you don't then I'd take a look at the oil temp sender values and the AIT. You also have to insure that the Motronic is not loosing any power through bad ignition, kill or ss switches.

    I strongly disagree that the 1100 requires re-chipping to have a good runner or for that matter even the CO pot. After the above you should be be getting closer to 50 mpg hwy if you keep it under 62mph and you're not heavy handed. At elevation I get in the 60's.
    #13
  14. Poway

    Poway SHED (Shit Head)

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    MPG's
    My 99 R1100GS 37mpg 100K (sold)
    98 R1100GS 35 mpg 19K
    99 r1100RT 39mpg 68k

    Never saw anywhere north of 40 mpg, on the gs's unless above 4000' msl.
    #14
  15. mousitsas

    mousitsas Long timer

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    bbpower chip.
    It does exactly what it says on the box and transforms the oilheads.
    #15
  16. mouthfulloflake

    mouthfulloflake Not afraid

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    Well, yeah I realize that now, I doubt I will tear it down just to clean carbon though.


    **Vintage rider, intake rubber boots are new, TBs do not seem to be too worn, in tank fuel parts are new.

    i have NOT replaced any throttle cables, but I do find it possible to synch the TBs

    great input everyone, I appreciate the collective wisdom
    #16
  17. tvpierce

    tvpierce Long timer

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    Subscribed.
    #17
  18. roger 04 rt

    roger 04 rt Long timer

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    Without the CO pot, the low RPMs can get very rich. Happy Wanderer took some data on this effect with his LC-1. The curve shifts by 0.6 AFR (a lot) depending on whether you ran pure gas or E10. The curve below with E10 shows how very rich low RPMs are, 12.4:1 and that would drop to 11.8:1 with pure gas. Also with E10, it's not much richer than Closed Loop cruise, a reason why your pinging might not have changed much.

    [​IMG]
    #18
  19. mouthfulloflake

    mouthfulloflake Not afraid

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    refresh my memory, I need a 1K ohm pot to adjust the CO?

    I use pure gas most of the time, but that rich bottom end would explain the muddy lower end.

    Thank you for your input Roger.
    #19
  20. Djunta

    Djunta Been here awhile

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    Carefully read all about tuning, I only have a basic knowledge about electronics. Rob Lentini said the surge comes from too many open butterflies, also from excess fuel as you have, variations in ignition timing, increased compression, backlash in the chain camshaft, clogged cat, burnt valve ... I would suggest you to check the TPS position, if you synchronize the left TB, you added too much fuel. No matter what synchronization looks good does not mean that all is well. Also TB cable we have, L, does not always allow to obtain proper synchronization and full performance at the same time. Although TB can not hear it does not mean that they are correct and that the butterflies are not damaged and leaking more than it should, idle stop position damaged and too close and MO adds fuel to compensate ..., you have a lot of things to check from the beginning. Some ideas, lower part
    http://www.advrider.com/forums/showpost.php?p=22994980&postcount=13
    #20