Honda Grom banner

1 - 13 of 13 Posts

·
Registered
Joined
·
37 Posts
Discussion Starter #1
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
 

·
Registered
Joined
·
133 Posts
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.
 

·
Registered
Joined
·
37 Posts
Discussion Starter #7
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.
 

·
Registered
Joined
·
37 Posts
Discussion Starter #8 (Edited)
Here's the US SF ECU pin configuration.

View attachment 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?
 

Attachments

·
Registered
Joined
·
8,366 Posts
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
 

·
Registered
Joined
·
37 Posts
Discussion Starter #10
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.
 

·
Registered
Joined
·
736 Posts
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?).
EU ecus have the cold start just like the US ones.
I asked DHM about a reflash and he said he had sold a few to the UK apparently without issue.

I wonder if the problem is not an OG / SF reflash issue, maybe you have one for OG when it should be for SF or something like that. I'd double check with Cameron.
 

·
Registered
Joined
·
37 Posts
Discussion Starter #13
Just thought I'd send a quick update on this one...

So I unplugged the battery, unplugged the ecu and managed to get the cover off the front of the plug.

With a small needle and a bit of fiddling, I was then able release the yellow/green wire from pin 22.

I then moved this to the empty pin 33.

I reconnected the ecu and the battery, started the bike up and hey presto! My tachometer is now working!

So to sum up... from the wiring diagram below it looks like on US bikes the tacho wire uses pin 33, as US bikes have something different occupying pin 22, EU bikes however have the tacho in pin 22 and have an empty slot at pin 33.

Hope this helps anyone in the same situation!
 

Attachments

1 - 13 of 13 Posts
Top