Fuel pump runs by turning tire???

[black_xb12r]

Have a very weird situation putting a crashed buell back togather...

Turn key on and the pump primes for the normal 3 seconds.

Now of you turn the back wheel even 1/4 inch the pump Will start pumping again...

I've never experienced anything like this... how does it even know that the wheel is turning? Has to be going through the transmission from the speed sensor somehow?

Any insight would be very helpful at this point!

Thanks
KC

 

[34nineteen]

Is it in gear when you do this?

If it is, then this is normal and part of the procedure for setting static timing on some models.

I will be doing the same thing tomorrow.

 

[black_xb12r]

No it is not in gear and the neutral light is on... I also get a bit of clicking once in a while when rotating the wheel it's coming from something by the injectors/intake but the only thing there to click is the injectors... I wouldn't think it could be trying to fire an injector without running but anything is possible...

Motor is a brand new rebuild not even fired yet was testing stuff going together and noticed the wheel thing when pushing it in the garage... I even went as far as jacking it up with the rear wheel off the ground and spinning the wheel by hand and sure enough it trips the pump on... I don't remember this on any of my previous xb's

 

[black_xb12r]

Fuel pump issue is sorted out...

Hasn't back through all wiring and found the problem... the pump was indeed firing off the rear wheel turning...

I hit a deer last May with my xb1250r with lightning tail which I've had for years. It was totaled for the most part so I found a used 12s on craigslist for $1500 with a bad tranny... my big bore motor survives the crash minus the front cylinder head from the front motor mount... so swapped motors into the 12s frame and used the wire harness that was in it.

However the previous owner completely screwed up the harness... some jack*ss swapped the 2 3 wire plugs by the front pulley for the cam sensor/ignition pickup with the 3 wire plugs from the speed sensor... normally the black plug goes to black and gray goes to gray...

Not the case in my situation... while not a big deal to just swap the plugs it took ALOT of troubleshooting to find that...

Thanks to anyone that read this and tried to come up with a solution!

Also I will have lots and lots of left over parts from my parts bike coming up for sale once I get everything wrapped up

Thanks
KC

 

[Cooter]

Glad you found it! That's a tough one....

 

[Chicknstripn]

Seems like a lot of guys are dealing with issues that stem from some jackhole not knowing what the hell they're doing with a bike. Glad you knew enough to check your wiring and didn't jump straight into fuel and ignition map swaps!!
Good work and thanks for posting back with your resolve.

 

[34nineteen]

Yes, that would have been a bear to diagnose.

So, the speed sensor was plugged into the cam sensor pickup? So the ecm was detecting pulses from the speed sensor and was triggering the pump.

Sometimes there are not enough facepalms!

 

[black_xb12r]

Yup speed sensor plugged into the cam sensor plug on the harness side...

Kinda amazed that the speed sensor generated the correct voltage to trip the pump through the ecm...

And chickenstrip I had that thought about maps cause I flashed the 1200 em with the map from my old 1250ecm as the mounting tabs broke off on the crash so I though something went wrong in the flash but I knew enough to check the firmware and everything and they were both the same as they were both 04 ecms but if wiring checked out I was headed in that direction to load back stock maps to see if it changed anything...

And I did facepalm myself when I figured it out and at least it wasn't totally my fault on this one!