Reflashed US ECU on a UK Grom, lost my tachometer, can I fix?
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Reflashed US ECU on a UK Grom, lost my tachometer, can I fix?

This is a discussion on Reflashed US ECU on a UK Grom, lost my tachometer, can I fix? within the Grom Talk forums, part of the Honda Grom Forums category; Hi, I recently purchased a reflashed ECU from Cameron Jones Racing for my 2017 Honda MSX SF. My bike is a UK Honda MSX and ...

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Thread: Reflashed US ECU on a UK Grom, lost my tachometer, can I fix?

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    Reflashed US ECU on a UK Grom, lost my tachometer, can I fix?

    Hi,

    I recently purchased a reflashed ECU from Cameron Jones Racing for my 2017 Honda MSX SF. My bike is a UK Honda MSX and the new ECU was a US model.

    Since adding the new ECU, the bike definitely runs faster, so I’m happy with that. The only issue I’m having is that the tachometer no longer shows any Rebs at all. When I first turn the key it goes up and down as usual, but then when the engine is started it shows no revs.

    Does anybody know what the issue may be. Do I perhaps need to move one of the pins in the ECU plug because of a difference between the US/UK Grom. Which wire would I need to move, etc?

    Any help would be amazing, as if I can get the tachometer working this new ECU would be perfect!

    Thanks

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    That's an interesting issue to have after switching the ECU. Did you contact Cameron Jones himself to ask him?

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    Reflashed US ECU on a UK Grom, lost my tachometer, can I fix?

    Sounds like you need to repin, I bet your harness is the same as the Asian bikes (assuming no cold start valve on your bike?).

    When I installed the finbro ecu years back on my 2014 grom I had to swap the tach wire for it to work. (I think it was tach and CEL wires?)

    Dig thru the forums, the answer will be here either in schematics or someone experiencing it themselves.

    For me, when repinning, I just use T-pins for sewing to release the tabs. They work great for nearly any connector and also for back-probing for diagnosing issues. I can get a bunch of these pins in our local supermarkets for less than $5.
    Last edited by Yfz460; 06-10-2019 at 07:56 AM.
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    Here's the US SF ECU pin configuration.

    Reflashed US ECU on a UK Grom, lost my tachometer, can I fix?-zbo74pk.jpg

    If you can find the UK ECU diagram perhaps you could compare them to discover the difference.
    Last edited by tooter; 06-10-2019 at 08:43 AM.
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    Correct you need to repin for UK groms using USA ECU
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    Quote Originally Posted by tooter View Post
    Here's the US SF ECU pin configuration.

    Click image for larger version. 

Name:	ZBo74pK.jpg 
Views:	46 
Size:	2.44 MB 
ID:	80828

    If you can find the UK ECU diagram perhaps you could compare them to discover the difference.
    Thanks, I’ll see if i can find the equivalent UK diagram.

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    Quote Originally Posted by 50-50 View Post
    That's an interesting issue to have after switching the ECU. Did you contact Cameron Jones himself to ask him?
    Yes and he suggested perhaps the tacho wire is located differently on UK groms. I just want to try and work out which wire it is and where I’d need to relocate it.
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    Quote Originally Posted by tooter View Post
    Here's the US SF ECU pin configuration.

    Click image for larger version. 

Name:	ZBo74pK.jpg 
Views:	46 
Size:	2.44 MB 
ID:	80828

    If you can find the UK ECU diagram perhaps you could compare them to discover the difference.
    I have this diagram in my Haynes Manual and can see there are a couple of wire that mention EU/US model specific. From this does it look like perhaps I need to unpin A22 and repin to A33?
    Attached Thumbnails Attached Thumbnails Reflashed US ECU on a UK Grom, lost my tachometer, can I fix?-img_8855.jpg  
    Last edited by afroade; 06-13-2019 at 05:45 AM. Reason: Updated attachment

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    Just for example, we in the USA when using a Finbro ECU "which comes from Thailand" we have to move around some wires on our USA ECU plug

    for us we have to
    pull the orange gasket and holder a part to get to the pins
    remove pin 28 "Yell/Org" and insert it into pin 20 "empty slot"
    remove pin 33 "yell/Grn" and insert into pin 28, leaving pin 33 empty
    remove pin 22 "yell/blk" and insert into pin 19
    remove pin 18 "wht/blu" and insert into pin 22, leaving pin 18 empty

    for the ECU plug our pin numbers go
    Pin 1 is blu/back-pin 11 is Pur/Blu, that is the first row
    Pin 12 is Blu/yell-pin 22 is Yell/Blk, that is second row
    Pin 23 is wht/yell-pin 33 is yell/Grn, that is third row

    Good Luck and hope this helps
    Last edited by CiscoSanJose; 06-10-2019 at 10:27 AM.

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    Quote Originally Posted by CiscoSanJose View Post
    Just for example, we in the USA when using a Finbro ECU "which comes from Thailand" we have to move around some wires on our USA ECU plug

    for us we have to
    pull the orange gasket and holder a part to get to the pins
    remove pin 28 "Yell/Org" and insert it into pin 20 "empty slot"
    remove pin 33 "yell/Grn" and insert into pin 28, leaving pin 33 empty
    remove pin 22 "yell/blk" and insert into pin 19
    remove pin 18 "wht/blu" and insert into pin 22, leaving pin 18 empty

    for the ECU plug our pin numbers go
    Pin 1 is blu/back-pin 11 is Pur/Blu, that is the first row
    Pin 12 is Blu/yell-pin 22 is Yell/Blk, that is second row
    Pin 23 is wht/yell-pin 33 is yell/Grn, that is third row

    Good Luck and hope this helps
    Great thanks for this, I was going to ask how you work out what number the pins are on the plug, but I think this answers it.

    I’m hoping it’s just the single yellow/green wire I need to move from 22 to 33.

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