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Thread: 2004 R1150RT pings when it's hot outside

  1. #16
    MOA #24991 Pauls1150's Avatar
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    Question - Why would it be "a bit off"? I don't have a GS-911, and on the bikes I've tweaked, the results were always either "improved", "improved just a little", or "no perceptible difference". Edumacate us - If I can do better, I certainly want to! Thanks!

  2. #17
    Registered User roger 04 rt's Avatar
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    Quote Originally Posted by Pauls1150 View Post
    Question - Why would it be "a bit off"? I don't have a GS-911, and on the bikes I've tweaked, the results were always either "improved", "improved just a little", or "no perceptible difference". Edumacate us - If I can do better, I certainly want to! Thanks!
    This is just me being me. Your number is inside the range that works. Once it's in the range, it doesn't seem to matter much.

    On my GS-911, it shows a range of acceptable voltages. It seems to me that the only way to know if you're in the center of your Motronic's range is with the Motronic output display--so that's the extent to which you could be "a bit off". The reality is, as I mentioned, that it is hard to do anything that the Motronic doesn't seem to take in stride on the 1150.

    As you know the 1150 TPS has two pots in parallel one for up to the first 20 degrees or so (can't find the sheet). The sensitivity of the first pot is 0.025 degrees per 5mV so 30mV is 0.15 degrees. I think the GS-911 is satisfied somewhere between 300 and 400 mV.

  3. #18
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    Quote Originally Posted by Pauls1150 View Post
    If your valves are set too tightly, that will also increase the operating temperature. Set 'em a little "sloppy".
    Setting the lash too tight (which I actually recommend - 2/3 of normal) effectively increases the "dwell" slightly, which effectively increases the compression ratio slightly. Which will lead to running a little hotter and more tendency to ping.
    Someone may need to correct me, I believe the compression on the 1150 is already 11:1, pretty high.

    Can you get 93 octane where you are?

    Check the hall effect sensor (ignition timing) plate - it has about 3 degrees of adjustment and if it is maxed out it can be too much under load.

    Spark plugs can be had in a lower heat range.
    Normal Bosch plug would be FR6DDC - the 6 is the heat range (6 is pretty much in the middle).
    You could drop to heat code 5 or 4 as an experiment.
    I doubt this will make any difference unless you run wide open a lot.

  4. #19
    MOA #24991 Pauls1150's Avatar
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    Thanks, Roger.

    Scott, having the valves "tight" also decreases the time that a closed valve spends on the valve seat. This reduces the transfer of heat from the valve to the head (more critical on the exhaust side), further increasing temperature.

    And for those who haven't seen the inside of the 1150 TPS, here ya go; this one is at almost closed throttle. The 1100s had windings of resistance wire instead of the carbon resistive elements. It's a bit more than just resistors in parallel, it's a nonlinear voltage-divider network.
    Attached Images Attached Images

  5. #20
    Registered User roger 04 rt's Avatar
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    Yes, it's a nifty beast. The specs show its output voltage for each of the two parallel potentiometers to be linear with rotation.

    http://www.bosch.com.au/content/lang...leposition.pdf

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    Quote Originally Posted by Pauls1150 View Post
    Scott, having the valves "tight" also decreases the time that a closed valve spends on the valve seat. This reduces the transfer of heat from the valve to the head (more critical on the exhaust side), further increasing temperature.
    yes, that makes sense, thank you. I had not thought of that.
    So far no issues with the 1100 running .004 and .009 - quieter with less of a sag at a certain spot of the powerband.
    Actual horsepower increase ? eh, not much I would say. Just a little more willing roll-on.
    I have not been out in the middle of the panhandle area at 104 F with this adjustment yet...

  7. #22
    MOA #24991 Pauls1150's Avatar
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    Thanks Roger, that's a great sheet from Bosch. But now I'm gonna have to spend a day ohming one out thoroughly just to see how it gets there...

    Another point, Scott: You may find it starts more easily and spins more willingly with looser valves. On my RT, the little bit of extra noise is muffled somewhat by the tupperware. It could also make the sync operation a little easier, since your gauge may see more vacuum to work with.

  8. #23
    Here For A Good Time! kconant's Avatar
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    Buckeyebill, I am not sure if you have solved your pinging issue.I had the same issue with my 01 1150GS for the first few months after I purchased it in 2010 with 42,000 miles on it. No matter what premium gas I tried it was still very prevalent especially when it was above 80 degrees.After adjusting the valves to BMW specs and having the TB's synched it was better, but not gone away. I purchased a Booster Plug and installed it and noticed even more improvement, but not totally gone.Finally, I unhooked the charcoal canister and took it off the bike and capped the ports on the bottom of the TB's and lo and behold, no more pinging under any circumstances. I must have had a leak in a line, or the in line valve was not functioning properly allowing air in to the ports all of the time, leaning out the fuel mixture. Just pull the hoses off the bottom of the TB's and cap them or pull the hoses apart and plug them and see if the pinging goes away or gets much better. I bought a bag of 50 caps and will send you a couple if you send me your address.

  9. #24
    MOA #24991 Pauls1150's Avatar
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    Worth a try. Not only to pull better vacuum, but to pull more constant vacuum - with each engine cycle, the internal volume of each hose is changing; those hoses up to the switch if everything is working properly, and all hoses + the canister when the switch is open.

  10. #25
    Registered User roger 04 rt's Avatar
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    Quote Originally Posted by Pauls1150 View Post
    Worth a try. Not only to pull better vacuum, but to pull more constant vacuum - with each engine cycle, the internal volume of each hose is changing; those hoses up to the switch if everything is working properly, and all hoses + the canister when the switch is open.
    Paul, This post gave me a great idea. I've got a lot of detailed AFR data and coincident GS-911 info. I'm going to look through a paired-set of files and see what happens to the AFR when the purge kicks in. RB

  11. #26
    MOA #24991 Pauls1150's Avatar
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    Good idea. My first thought is that there will be a "moment" of extra-lean, then the computer should sense that and try to compensate for it - provided, of course, everything is working "ideally".
    Paul S

  12. #27
    Registered User roger 04 rt's Avatar
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    Quote Originally Posted by Pauls1150 View Post
    Good idea. My first thought is that there will be a "moment" of extra-lean, then the computer should sense that and try to compensate for it - provided, of course, everything is working "ideally".
    Paul S
    It will be interesting to find it and see (which I haven't done yet). It's possible that since the Motronic knows it is opening the valve, it tweaks the fuel up a bit. I'll try to look at it tomorrow.

  13. #28
    Registered User roger 04 rt's Avatar
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    Quote Originally Posted by Pauls1150 View Post
    Good idea. My first thought is that there will be a "moment" of extra-lean, then the computer should sense that and try to compensate for it - provided, of course, everything is working "ideally".
    Paul S
    I looked through several log files. Here's what I see at the moment:

    My dual spark 1150RT, once warm, opens the valve for three minutes and closes it for 2 in a cycle. When it opens or closes there's a brieft lean/rich blip about 6 seconds after the valve changes state. The lean/rich blip lasts for about a second and then it's gone whether open or closed loop.

    A friend has a single spark 1150GS. It opens the valve and leaves it open once warmed up, except every 8 minutes it blips closed for a second, no effect on AFR.

    I don't know if the purge difference is the single spark vs the dual spark MA 2.4 (there are other non-obvious differences I've spotted, e.g. O2 input measuring circuit) or if it is governed by the Coding Plug. My guess would be single vs dual MA 2.4. Another difference, not that it is relevant to this is that the O2 sensor on the GS is remote enough from the engine that the Closed Loop period goes from 1-2 seconds most of the time to about 5 seconds at idle. It takes that long to purge the exhaust system as far as the front of the cat.

  14. #29
    MOA #24991 Pauls1150's Avatar
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    Wow, that's really pretty odd, for both cases.
    The alleged purpose of the whole canister setup is to purge excess fuel fumes from the fuel system, while not permitting these fumes to vent directly to atmosphere.
    In the single-spark system, it doesn't make a whole lot of sense to me that it would be "open" so much; that would incur a loss of vacuum and a waste of fuel.
    In the twin-spark system, it brings up the question "How often does it cycle?" - Seems that any gas tank + injection system in good condition shouldn't need "constant" (tho intermittent or cyclic) purging. Additionally, 6 seconds seems like a loooooong time for the computer to react and adjust the mix.
    Sounds like more reasons to nuke the whole shebang.

  15. #30
    Registered User roger 04 rt's Avatar
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    Talking about nuking it a guy wrote to me who has put megasquirt on several vehicles. I don't think we need to go that far. In the case of the purge valve we've been living with it for a long time.

    I'll look at it some more to double check, but the 2004 RT opens the valve for 3 minutes and closes it for 2 minutes constantly once the engine is warm. Although I can see the effect with the LC-1, I don't think it can be felt, the volume of air must not be much.

    The 6 seconds I referred to isn't how long it takes the Motronic (which is quite fast), it is the time between the purge valve operating and when the AFR is disturbed and when you can see the effect at the input to the LC-1 (assuming I'm interpreting the AFR chart correctly). Btw, the LC-1 is very fast so it's not a factor.

    I would not have been inclined to look as far as 6 seconds downstream but on the 1150GS, if the Motronic commands a sudden change in injector time while idling, it is a few seconds before that richer/leaner exhaust reaches the sensor. I'm sure that's hard to believe, but I've measured it several times.

    There are all kinds of minor Motronic functions that aren't documented and major ones too. BMW truly wants it to be a black box.

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