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Idle stepper motor OR magic box (ECU) issue

Discussion in 'Stelvio Chat & Tech' started by gringo, Jun 22, 2020.

  1. gringo

    gringo Just got it firing!

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    Just took our new to us 2017 Stelvio on a 800 mile weekend trip to the Redwoods.
    Noticed a couple times it would die after a cold start in the AM but fine when hot, also had increased popping on downhill runs.
    IAC valve or something in the FI / ignition realm?

    I think this Bike is the best all around, for me anyway. I can't wait to ride it.
     
  2. scottmastrocinque

    scottmastrocinque Scott Mastrocinque GT Famiglia

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    Welcome to the Stelvio fold! They are simply awesome machines for sure. I’ve been enjoying mine since 2012!

    It is impossible to diagnose over the internet, a running issue like you are experiencing. There are so many unknowns.

    Is your bike stock? If not, what modifications exist right now? What is the mileage? When was the last valve adjustment done? Is the exhaust leaking anywhere? Last TPS reset? Steeper motor cleaned?

    Lots of unknowns...

    Yes, basic idle functions rely on the steeper motor working correctly, (carb cleaner works wonders when sprayed into the steeper motor intake) and a search of that here will give you plenty of posts of information to read.

    If you want to understand your throttle bodies, please read what I wrote here about it. It’s long but highly informative.

    https://www.guzzitech.com/forums/threads/syncing-throttle-bodies-stelvio-8v.9082/page-2

    Also, cleaning the stepper motor is discussed by John Zibell, resident super smart mechanic, here.

    https://www.guzzitech.com/forums/threads/stelvio-idling-issues.19986/#post-156502

    For fueling mods, I have had Todd’s full monty fueling setup with the PCV and autotune, and my bike is the best running Stelvio I have ever encountered. Well documented on the forums here.

    https://www.guzzitech.com/forums/threads/first-ride-fueling-kit.20241/#post-159684

    Read some, digest and ponder, collect some information on your motorcycle, get back to us here, and we’ll see what we can do to help you out!
     
    tobinh likes this.
  3. gringo

    gringo Just got it firing!

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    Thanks for all the info
    It definitely has all the makings of the IAC valve misbehaving
    That’s where I’ll start.
    It has 37000 miles
    My 09 Stelvio never gave me any trouble like that
    Hopefully it just needs a little TLC 5CD72FEA-31D9-435F-8162-398986575836.jpeg
     
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  4. gringo

    gringo Just got it firing!

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    Well, I cleaned the IAC and Throttle bodies, synched and reset TPS and all that jazz. idles fine now but still pops a fair amount on decel.
    maybe that just how it is, is there a way to tell if the o2 sensors have been disabled? I don't get a fault code but I also don't get any Lambda readings on the confuser screen
     
  5. scottmastrocinque

    scottmastrocinque Scott Mastrocinque GT Famiglia

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    This is one of those truly subjective things that is impossible to reconcile on the internet.

    Stock pipe decel popping was the norm on my 2012 Stelvio until I did the full fueling mod setup from Todd. It wasn’t terribly frequent or bad but it was there for sure.

    I found that abrupt shutoff of the throttle made it worse while smooth roll on and roll off, improved it markedly.
     
  6. gringo

    gringo Just got it firing!

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    Re cleaned everything and syncd and rebalanced etc etc. So we did a 1200 mile journey thru OR ad ID it was fantastic( highly recommend the road from Joseph to Halfway), no popping to speak but idle issue came back, it drops to 900-1000 and takes a while to come back to 1200. She's a finicky one I must say, well I figure it out eventually...
    On another note my rear Michelin Trail tour tire sure wore down on the sides and it wasn't all that hot, not sure if it's meant for a lighter bike
    ours is at 1100 lbs fully loaded prob go to an Angel GT next time
     
  7. scottmastrocinque

    scottmastrocinque Scott Mastrocinque GT Famiglia

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    When you did the FI throttle body balance, did you only open 1 side’s air bleed screw?

    I’ve seen this behavior when both were opened by mistake.
     
  8. gringo

    gringo Just got it firing!

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    Good to know thanks
    They were both closed, opened one up, Increased the CO trim to + 20 seemed to idle better at the time. Mama mia it really is a silly setup That they came up with about ready for carbs again
     
  9. scottmastrocinque

    scottmastrocinque Scott Mastrocinque GT Famiglia

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  10. gringo

    gringo Just got it firing!

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    Oh I read it.
    I had it perfectly set up prior to our last 1200 mile ride and now it’s acting up again. It shouldn’t need that much attention for a two adjustment system even a 70s Dellorto stays in tune longer
    Maybe the PO messed with the right TB screw.

    I love the Bike but little niggles like that are a nuisance. This winter I’ll dig into it when I have time and send the ECU to Todd for a map, but I can see a VFR 1200X in my future if she’s being a bugger
     
  11. scottmastrocinque

    scottmastrocinque Scott Mastrocinque GT Famiglia

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    Your comments cause me to question your understanding.

    You realize that it isn't about left or right with the air bleed screw? It's about opening the side that has MORE vacuum than the opposite side, and this is how you balance idle between the two intakes.

    Also, saying that you adjusted the CO trim to +20, tells me that you are almost certainly messing with GuzziDiag which has screwed up more motorcycles than I care to remember.

    What you have done with that CO trim +20 setting, is increase the real-time injection pulse-width by 200 micro seconds, across the throttle RPM range. This type of change will create a non-linear result across the entire throttle range.

    If you do not absolutely understand what I just said here, inside out, forwards and backwards, then you are really messing with your bike in a catastrophic haphazard manner, and poor running will be your lot in life.

    I tell you with 100% certainty, that when properly maintained, clean, and with no vacuum leaks or mechanical conditions to the contrary, the Stelvio will idle perfectly every day and twice on Sunday.

    The PowerCommander IV and the Autotune setup that Todd sells here, (of which I have both and highly recommend it) makes the bike run unbelievably better in all conditions.

    If your bike is not idling correctly, the answer IS NOT in modifying ECU settings with GuzziDiag. It's in establishing exactly what is not operating correctly or what is not configured correctly. The fact that you have issues, tells me that you do not have it as cleaned and adjusted as you think you do.

    FWIW: My 2012 has run perfect for 8 years now because I routinely clean the stepper motor intake and setup everything else exactly to Moto Guzzi specifications.
     
    GT-Rx® and john zibell like this.
  12. gringo

    gringo Just got it firing!

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    I get it Scott, I appreciate you helping me I followed the procedures in your write up and it works for a while....
    If I can set up a Aircraft Engine Fuel Control I should be able to follow a few steps for this thing

    I am just frustrated by it going out of tune in a matter of a long ride. Even my 71 Fiat didn’t do that!
    It could be something as simple as a sensor wire having gotten pinched and giving bad readings, vacuum leak or maybe the TBs worn like a SU carb used to do, yep that’s how old I am, of course in those days you could tune them by ear.

    Don’t get the Diag hate it’s just a Analyzer tool just like PC.
     
  13. gringo

    gringo Just got it firing!

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  14. scottmastrocinque

    scottmastrocinque Scott Mastrocinque GT Famiglia

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    I understand. I’ve given you the answer to your question. You just don’t like it or believe it. I cannot help you with that so I’ll leave it by wishing you “Good Luck!”.

    Diag hate? No. Not at all.

    It is my experience that 99.8% of the people who get involved with that “tool”, actually have no idea whatsoever about what they are doing with it or the severity of the damage they cause. (FI is not simple. It’s the most highly complex aspect of a modern motorcycle. I have several detailed textbooks on the topic, hundreds of pages in length each!)

    Diag users as a whole do not keep accurate records of what they did, and they invariably end up having a bike that doesn’t run right, and then blame the bike, or Moto Guzzi, or Piaggio, etc. and then they eventually wind up here seeking support for their poor running motorcycle.

    Unfortunately, they never consider themselves as the proximate cause.

    Many of them “lobotomize” their ECU’s and destroy the FI mapping so badly, and then come here looking for a solution for the “Pandora’s Box” that they opened, or worse yet, they “brick” their ECU’s, begging anybody to help them because the Diag people won’t.

    That “tool” is a recipe for for disaster for most people. It is not an “analyzer” nor is it benign like an OBD-II scanner. It has the capability of causing massive damage in the hands of professional mechanics, let alone the amateur.

    In my opinion and experience, it’s like performing brain surgery on yourself just because you could get your hands on a scalple.
     
    Last edited: Jul 20, 2020
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  15. GT-Rx®

    GT-Rx® Administrator Staff Member GT di Razza Pura

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    See; https://www.guzzitech.com/forums/threads/guzzidiag-notice.16329/
    No hate, just that I have lived in Guzzi-focused injection since 2001, and I have worked very hard and spent an enormous amount of money to help develop products, that not only are commercially supported, but also have the science and dyno runs to back my efforts.
    There was a commercially supported software that was used by the dealers for almost 20 years, that I had available here on the site... that is now gone thanks to Diag.

    Would you use a home-brewed electronic software to set up an Aircraft Engine Fuel Control? Maybe I don't want the answer to that. ;)
     
  16. gringo

    gringo Just got it firing!

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    Fortunately most helicopters are still operating hydro mechanical fuel controls, think the old Alfa SPICA!!! Only a lot more reliable, a few have FADEC ( Full Authority Digital Engine Control)

    I don,t blame you for not liking Diag with all the work you put into it, I only downloaded it to reset the silly TPS. Being old school I like to be able to adjust things, that’s why I said I’m about ready to slap some carbs back on it, got a conversion kit available??
    I’m sure I’ll figure out what causes the thing to go out of tune all the time. This is only my second bike with FI (09 Stelvio) But even my Valkyrie with SIX carbs was less labor to keep purring.

    Italians should stick to design , mechanics and leave computer engineering to others, you can’t have Chianti at lunch and expect things to work after
     
  17. gringo

    gringo Just got it firing!

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    CD3824EB-14DC-4A86-8889-343FC7FFA351.jpeg

    This might explain it, I rather work on my old 66 Volvo Wagon than my wife’s Mini Countrynightmare!!
    Cheers everyone
     
  18. john zibell

    john zibell Moderator Staff Member GT di Razza Pura

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    Maybe you are adjusting too much. I've been running FI bikes since 1993 and had no where near the issues you are having.
     
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  19. gringo

    gringo Just got it firing!

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    It’s been at most a quarter turn to sync at 3000 and maybe open the air screw 1/16-1/8 and she runs fine for about 500 miles. I marked the adjuster screw and it doesn’t move. I did try the CO trim just to see if it would change things but I put it back to 0, don’t know much about it’s history maybe somebody put a different map in it or messed with the sacred screw or my valves change clearance Willy nilly, but I suspect some intermittent issue (O2 or temp sensor??) and those are always a hoot to track down, if the ECU is wonky you’d think it would always act up. It will have to wait until fall now. I do have some FCR flatslides sitting around tho !!
     
  20. GEEG

    GEEG Just got it firing! GT Contributor

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    I also own a 2017 1200 NTX. Do yourself a solid and get Todds exhaust system a good air filter and TODDS airbox ring. Take the charcoal filter and plumbing off. Get TODDS powercommander V with the autotune module. Follow TODDS setup instructions and you will have a perfect running STEVIO! Worth every penny you spend on it!
     

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