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Ecu Reflash

Discussion in 'Technical / Mechanical Discussion' started by IzNoO, Aug 19, 2014.

  1. IzNoO

    IzNoO Member

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  3. IzNoO

    IzNoO Member

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  4. JamesK

    JamesK Super Member

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  5. blackizzz

    blackizzz Super Member

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    I'd look at the FI/diagnostic tool and how that connects, and mimic that, otherwise I'd say that the ports on the bottom right are the ones you're looking for, however, do you have a program capable of accepting the hardware? My guess is no... Which means that it'll be almost impossible!


    Sent from my IPhone
  6. IzNoO

    IzNoO Member

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    same ecu here...
  7. Mysterious Rider

    Mysterious Rider Moderator Staff Member

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  8. blackizzz

    blackizzz Super Member

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    Look at the video, you have your answer there, you need to buy a converter box or something like that (the black thingy left of the computer)
  9. Billy K

    Billy K Super Member

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    Chances are the converter is some sort of serial-USB box. I have no idea what type of connection the ECU uses. could be I2C if you are lucky but I doubt it.
  10. Killachipmunk

    Killachipmunk Moderator Staff Member

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    Way over my head there...
    I know that various people have tried, but as far as I know all of them said the stock ECU is no good, Yamaha never gave out the software to anyone or something. That's as far as I know on the matter.
    Top of this page is someone it's worth looking at, he did a lot of work on this ECU but looks like he reckoned it was secured:
    http://www.yamahar125.com/threads/rev-limiter.3791/page-5
  11. Billy K

    Billy K Super Member

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    I was doing a bit of searching as well. I'm not even sure that there is much logic inside the ECU. As far as I can tell it's mostly SOC logic controllers. So probably only pull a few variables from ROM chips, or something similar.

    If someone wants to send me a spare ECU, I'll let you know lol
  12. Killachipmunk

    Killachipmunk Moderator Staff Member

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    Wouldn't be surprised... It's a very simple control loop. As far as I know the bike does fuelling based on a very simple open loop: Throttle, Revs, Temperature and Airflow variables. There's no closed loop lambda sensor and no check/adjustments on the exhaust side of things
  13. Billy K

    Billy K Super Member

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    Does it even check temp for fuelling? I thought it was just for "Turn fans on now" haha
  14. Killachipmunk

    Killachipmunk Moderator Staff Member

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    I think there's an air temperature sensor in the intake tract somewhere. I'd check but I don't have the bike anymore! Will just have to trust my own memory haha.
    I wonder as well if the 2014 model is any more advanced...?
  15. blackizzz

    blackizzz Super Member

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    There is an ambient air temperature sensor at the throttle body :)
    Killachipmunk likes this.
  16. Al B

    Al B Well-Known Member

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    The workshop manual says the Yamaha FI programmer plugs into the 'self diagnosis connector' in the yellow/blue wire that connects to the dash. So there's more on that line that just a voltage to blink the fault light. It probably uses a serial signal for the programmer to ECU comms. If the ECU streams data out, so the programmer can see what's happening with sensors etc whilst the engine is running, then it should be feasible to connect the serial line to something like Hyperterminal or Portmon on a PC and watch the bits arrive. It might need some tinkering with baud rates, parity etc to get the settings right but when you hit the sweet spot some pattern of data should become apparent.

    This http://www.strangely.org/emerald/format.html is how someone did it with an aftermarket car ECU. I used the info to make up a software 'dummy ECU' to feed made up data into the programming software and work out what the remaining data channels were. Now I can record the serial stream into the data logger and analyse what's going on.

    To see how to reprogram the ECU you'd need to get hold of the FI programmer, then you could tap into the comms and see what messages go back and forth when the various functions are selected.


    If you could manage to work out the ignition advance mapping then that would pave the way for using aftermarket ECU's. Fully programmable systems cost about the same as the power commander etc fuel fudgers.
  17. Billy K

    Billy K Super Member

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    You could just pass the signal through a microcontroller like an arduino and adjust the baud rate on the fly. Getting information out should be simple, getting usable information out, isn't.
  18. vinasource

    vinasource Member

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  19. Nox_templin

    Nox_templin

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    It's possible that the YZF R125 may use the same setup as other Yamaha in which the Yellow/Blue wire is a K-Line communication line ,in which case there are several OBD and ecm flash/hack systems that may be able to interact with the system
    NorthCust likes this.
  20. misiozol

    misiozol Member

    those days is pointless to spend any money on flashing cable as custom ecu that gives lots of more is in range 100-150e

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