1125r Fuel Pump Fuse blows, even before the fuel pump should be priming.

[JohnL]

Hi. 2008 1125r. 1300miles only.

Not sure if this forum is still active, but this is my problem. I let the bike sit for 6-7 years and am trying to get it running again. I drained the fuel and replaced it. I got it running, then it started to blow fuses. I haven't yet checked for shorts. Is there a common area or issue that would cause this?

When I disconnect the pump harness (86A/B four pin connector), I am able to 12V jumper the red and black wires on the pump harness and pump fuel (the fuel pump spins/runs fine.....so that means the diode is ok, I suppose. I disconnected the fuel line from the injectors and can pump the fuel into a bucket).

All I have to do to pop a 15AMP fuel pump fuse is to connect the four pin connect (86A/B) and it immediately pops.... even with the ignition off. Sounds like a short to ground. So, I'll try to run the wires this weekend. Trying to avoid removal of the fuel pump.
Thanks in advance.
John

[Barrett]

Unless there's visible signs of vermin feasting on wiring looms or "rub-throughs" of the pump wiring harness....unlikely there's a positive feed wire short in the pump harness. The 1125 fuel pump is unique in that it's pulse-width modulated AND the ECM directs it to ground to cycle the pump motor on and off. When you jumped the fuel pump harness you were in essence providing unlimited 12V positive amperage to the pump motor forcing it to turn on. NO fuse to pop. Sounds reminiscent of either a small short-to-ground of the pump internal wiring loom or failed electric pump motor.

Check for continuity at the OR/GR wire as that is the electric pump motor 12V + feed.