996 Tacho Not Working

Discussion in 'Newbies Hangout' started by Dallypro, Jun 14, 2025.

  1. All that info, without paying a fiver?
     
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  2. This is great news. It took some research to come up with a solution. Thankfully, it was a cheap solution. I had all the bits to build it in my stash of connectors and components. If I get chance I will post the schematics for the device and get it made a sticky. As these bikes get older the electronics will start playing up. If you see a cheap ECU or dash on eBay then buy it and squirrel it away for a rainy day.

    Glad to have helped out. Pay it forward.
     
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  3. I think myself extremely fortunate and will certainly do my best to aid anyone where I can.

    It's been quite the crash course, and without the support of this forum (and special mention to ChrisW), I am confident that my Tacho would have never worked again!
     
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  4. @El Toro is there a way to extract this and make it a sticky in the technical section.

    The circuit was developed to address an issue on an IAW16 ECU but it may work on other ECUs that use a square wave on the Tachometer signal.

    The idea is that the square wave signal is boosted to 12v.

    Components needed
    1 x N27000 Mosfet
    2 x 1 KOhm resistor
    Copper backed circuit board to solder components onto
    4 x lengths of wire
    The only wire from the ecu that needs cutting is from Pin 24 on the ECU to the tacho

    IAW16 Tacho mod.jpg
     
    #204 chrisw, Jan 18, 2026
    Last edited: Jan 18, 2026
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  5. I think it's very kind of you to supply details Chris - I can think of several other professions where they would sit on this in secrecy and cash in at the appropriate time.
     
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  6. I second this 100%
     
  7. I agree, this should be a permanent guide on the technical section. However I did read recently that P8 ECU tacho's are not compatible with IAW 16's???
     
  8. Well you could click on front page then premium subscription? Just a suggestion?
     
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  9. I have just subscribed
     
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  10. I have to just say that was an impressive bit of work by chrisw. Very well done on the fix. :upyeah:
     
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  11. It's well worth the £5
     
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  12. 10/10 for homework chrisw I have saved that.
     
  13. Evening all

    I thought I would just finish up by showing the final result on the bike (see pics)

    Apologies to ChrisW in advance. He is going to notice that neither of his have made it onto the bike. This is purely because I'm a ham fisted moron and broke them both.

    So.....I bought the bits and made a third one exactly as he has described.

    To fix to the bike, I disconnected the ECU plug and stripped back the loom covering. I then cut the green/grey and the brown wires

    The gizmo was then soldered in, and then everything was bound up onto the loom so it's tidy (ish). The earth is the ECU fixing.

    Tacho is 100% working and we are away.

    Thank you once again to everyone on the forum, and absolute Kudos to ChrisW and his electronics knowledge!

    If anyone comes across this post and needs one, and can't get hold of ChrisW, let me know as I have enough stuff to make about a million of them.

    IMG-20260130-WA0005.jpeg

    PXL_20260130_203257034.jpg

    PXL_20260130_203844522.jpg
     
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