Yamaha WR250F ECU

[jaggers]

My fuel pump stopped fortunately near home rather than half way down a muddy track. I worked through the Yamaha manual trouble shooting list and the final line said replace the ECU. In addition, I bench tested the pump and it worked. The cost of the ECU is £471 from Yamaha. Strangely, there is no relay powering the pump, the pump’s 12V terminal is permanently high, and the 0V terminal is grounded by the ECU. On eBay I can get a GYTR completion ECU from the USA for about £100, however I might need a Tuner to map the ECU costing about £350, again from the States. I assume this is all grey market stuff. I think the ECU switches the pump on when the ignition is live, and stops the pump with the engine stop button. I assume the ECU does not modulate the pump depending on demand. I could wire the pump directly to the ignition circuit, bypassing the ECU, which would mean the pump will run after the engine has stopped until the ignition circuit dies which is about 60 seconds after the engine stops. I don’t think this would be a problem. I don’t want a manual switch because I am bound to forget it and leave it on. Does anyone have a better idea ?

[19col58]

Good luck with this, I was going to offer my thoughts but having looked at my 450 manual it's way above my pay grade! All I will say is don't be tempted to run the pump permanently.
Take the bike to a dealer who has the necessary diagnostic equipment. It may be cheaper in the long run.

Colin

[stevent]

Presuming this is a newer WR F (2016-)

I have the power tuner and it has a monitor mode.

“Monitor function allows user to monitor the data from various sensors on the bike as well as adjust idle timing, see engine running time, and self-diagnosis function.”

Do you want to borrow to see if helps diagnose?


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[jaggers]

Yes, my WR250F is a 2015 model with the exhaust coming out of the rear of the cylinder head. I hotwired the fuel pump bypassing the ECU and tried to start the engine. All indications were normal and the pump ran and you could hear it slowing down as the pressure built up. However, the engine turned over with the electric starter but it did not fire. So as advised, the next step is to use a power tuner to diagnose the ECU. Thanks Steven for your offer of using your tuner. Unfortunately, I can’t make club night this month because I could have bought the bike on the back of my truck. I’m off for a bit of sunshine next Tuesday, when I get back I would like to take up your kind offer.

[19col58]

I have a Power Tuner, Fmf pipe and other parts on Ebay right now. Currently bidding at £210, ends Sunday evening. I'll see if I can share it to you. If you're not interested in mine then Motowards in Rudgewick sell them for £232!

Colin

[jaggers]

Thanks Colin, I'll check that out. Ian J.

[jaggers]

Thanks to Moto-Ward , Rudwick, my bike has been fixed. Turns out that some connectors were eroded and not making contact. Andy wasn’t sure which one so he cleaned all of them. He said that he has seen this before on the WR250. I was convinced it was the ECU, costing loads, so was really relieved when the bill was £55. I highly recommend Moto-ward, very helpful and friendly people.

[stevent]

That’s good news! What a simple fix.


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