**Fuel Injector Overfueling** - .: XT660.com

RickM · # 1 24-08-10, 16:14

Just had my first "major" issue with my 09 Ten and thought I'd better share it in case there is a common problem (my dealer has asked for photo's so he can inform Yamaha).

Whilst returning home from Birmingham last Thursday I ran out of petrol prematurely after only 59 miles on reserve instead of the usual 80-90 miles.
I normally ride at half to three quarters throttle hence 60-65mpg. As reserve is 6.3 litres, 59 miles equates to about only 42.5mpg!! Even allowing for thrashing the bike, the lowest I've had previously was approx 55mpg.
After a little top-up the bike wouldn't start but stunk badly of petrol.

Spent most of the weekend checking all the usual culprits to eliminate them. On the one occasion that I did manage to briefly start the engine a considerable amount of unburnt petrol was ejected from the silencers - not the usual misfiring situation I've experienced before with previous bikes!

Whilst checking the injector (I assumed it had stuck open somehow) I noticed signs of corrosion around the FI lead and frame.

The FI lead exits the wiring loom between the loom and the frame. As such the paint had rubbed off the frame and the red/black wire of the FI lead (to ECU) had chafed to the bare wire and so was shorting against the frame!! My first thought was "that's a clever bit assembly-NOT" (or words to that effect!)

Needless to say, bike runs fine now that I've patched it all up.

Being a courier I do alot of miles - over 51,000 since end of March 09 - but regardless of more than average wear and tear this struck me as a breakdown waiting to happen.

Might be worth Tenere owners checking their wiring loom just in case.......especially if they experience misfires/bad running with excessive amounts of unburnt fuel.

And put some foam between the loom and the frame

Hope this is of use.

Cheers,
Rick

PS. Do the X's & R's share a similar wiring loom???

Skunkmoto · # 2 24-08-10, 17:06

When I put a powercommander on I noticed the very same thing, and put a bit of foam tween the wires and frame.

Thought I'd posted something on this see here http://www.xt660.com/showthread.php?...highlight=loom

RickM · # 3 24-08-10, 20:22

Well b*gger me!

I obviously missed that one. Just shows how sensible you were!!

Kev · # 4 24-08-10, 23:25

Nice find that would explain the extra fuel.

The injector works off a Pulsed Width Modulated signal with the ECU controlling the earth side of the injector, if you earth that wire out the injectors duty cycle will up to a 100% depending on how good the wire was to ground.

RickM · # 5 25-08-10, 01:33

Thanks alot for confirming that Kev.
When I tried to explain the situation to my dealer (I was worried about the petrol in the oil and any subsequent warranty issues) the young mechanic got all text book like about switched earths unlikely to be from the ECU. I was starting to wonder if the FI lead was just a coincidence to my problem. 100% duty would explain the amount of petrol in the engine oil!!

I guess the FI lead is potentially just another addition to the list of known issues???

Anyways, the Tenere is still a great bike - at least it was at last years price!!

Kev · # 6 25-08-10, 02:07

Thanks for this info, it is one to watch out for, I am sure all the XTZ boys will check their looms as soon as possible, I know i would be checking mine if I owned a XTZ.

This have given me an idea to make a section in the XTZ mod index of K now Faults & Fixes to a XT660Z, now loacted at the end of the XTZ mod index. I will get all the other know faults & add it to the subject soon.

http://www.xt660.com/showthread.php?t=630

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