Faulty ECU?

[Nagasaki]

Just need some opinions on this as I think my ECU is faulty.

The bike does run and work with all lights etc working and so on.

It's just the bike does not rev up to 2k rpm on cold start like it should. It was working intermittently but not any more.

I noticed that the clocks on this bike are not the correct one as they should be white not black. And the white speedo/clocks like on my stolen YBR Custom had a diagnostic light on the right side vs on the black one a right indicator light. Some non custom YBR's do have the same diag light on the black clocks but most just have the indicator light. And to confuse it even more there's a 3rd style of clocks. I suppose I could buy the 3rd style that does have a diag light too but id have to check the wires are the same.

I want to get the white version but they are expensive when they pop up.. The reason for this explanation is to cover what I was trying to do today.

So I thought I could just wire that diag wire to the right indicator light and use it as my diag light. There is a wire in the connector of the loom that does not connect to anything in the connector to the clocks and the wiring diagram confirms this is the wire that would go to that diag light if I had the right clocks for the bike.

But up on trying to get this working I found that I'm not getting a voltage on that wire when turning on the ignition. When the fuel pump primes the diag light is supposed to come on.

I say no voltage, there is but it's wrong. When I turn the ignition on I am getting -0.25 volts. Once the fuel pump stops priming the voltage is 0. When forcing an error by unplugging the fuel pump the voltage starts bouncing around between 0.2v and 1v

From that behaviour I am guessing the ECU is a little faulty. Do you think the same?

A replacement on eBay currently is £40 or more so I don't want to spend that money and have it not fix the issue with the diag light and the bike not reving up when cold. Especially while I am only getting SSP. (Back to work in about 2 weeks)

[NorthumBryan]

It may not be the ECU. If the wiring & light is not as the ECU would expect to 'see', it may be causing the issue. The standard wiring impedance (all the wiring, the resistance of the LED bulb, any switches & sensors etc) will be what the ECU expects when it runs through it's diagnostic programme. If the resistance of the circuit does not match the ECUs programming it may either see it as a fault or because it's out of specification not see it as a fault. It depends how it's coded and how basic it is?
My work colleague is having this issue with a BMW car. It's not fuelling properly, but it's an older model and the ECU isn't advanced enough to spot the fault. Whilst I fully appreciate pennies are tight at the moment, it would be worth getting it plugged into a Yamaha diagnostic tool (dealer/specialist) to give you the definative answer. It may work out cheaper in the long run. Best of luck with it though 

[MadisonMotorsportUK]

Are you sure that the wire you have concluded is the diag wire definitely is the diag wire? Maybe try connecting it to it's own bulb so you're not shorting two circuits together.

I doubt the ECU is at fault, they rarely fail and when they do it's usually down to user error.

[Nagasaki]

Are you sure that the wire you have concluded is the diag wire definitely is the diag wire? Maybe try connecting it to it's own bulb so you're not shorting two circuits together.

I doubt the ECU is at fault, they rarely fail and when they do it's usually down to user error.

100% sure.
I even found the "connector" behind the side panel. Attaching a bulb to it or a multi meter shows no voltage at that connector. Its just 1 wire with bullet style end on it.

I found a yam dealer in Peterborough. It was Webbs but not since October. Will give them a call and see if they can give some insight.

[NorthumBryan]