My K1100 has/had an extra wire running from the front injector up under the tank somewhere. This has now broken off and nothing now works. Has anybody any idea on what it might have been connected to? I'd like to remove it completely as it is obviously a bodge.

I'm going to guess it was a 12v feed to the injectors.  The Motronic fires the injectors by grounding them.

I think I'm with .75. The 12v feed should be a green/red wire.

The previous owner may have added the wire to correct a problem with the ECU, the ECU connector or the injector harness that was preventing the injectors from getting power.

Rockman wrote:My K1100 has/had an extra wire running from the front injector up under the tank somewhere. This has now broken off and nothing now works.

Does nothing now works mean there are no lights, no starter and no fuel pump activation?

Laitch wrote:

Rockman wrote:My K1100 has/had an extra wire running from the front injector up under the tank somewhere. This has now broken off and nothing now works.

Does nothing now works mean there are no lights, no starter and no fuel pump activation?

No fuel pump activiation. Lights etc are removed at the moment. I wonder if I have a blown fuse as well - I'll have to check this.

Previous owner has on knowledge of it, but has a complete wiring harness that he is sending me. As it is coming apart for refurbishment I think I'll fit the new harness during reassembly and will probably cure the problem in the process.

wow, another k phil ?

do you need help ? im not far off ..

but it does sound like you have blown a fuse  or a bad kill switch issue

charlie99 wrote:wow, another k phil ?

do you need help ? im not far off ..

but it does sound like you have blown a fuse  or a bad kill switch issue

Slowly slowly with this one Charlie.

Well, I found part of the problem. Rick had put an Anderson plug in the leads from the battery. This had literally fallen apart (the plastic parts of it) and I no longer had a connection. I repaired this so and the starter etc now works, but not the fuel pump.

Does the 12v feed for the injectors go via the temperature sender or something so it will cut off when the bike overheats? Maybe the fuel pump is similarly controlled. Dont know yet.

normally the ecu sends the relay trigger for the fuel supply , from memory on ignition on the fuel pump should sound for a second or so 

side stand issue perhaps ?

Side stand switch was bypassed so may pay to check the scotchloc at the plug under the right side cover

I could hear the fuel pump for a second or 2 but this all changed when the extra wire broke so I think the problem lies there.
Anyway, doesnt matter now as I have started disconnecting wiring so that I can remove the frame for repainting. I think most problems will resolve themselves when I start reassembly.

Or get worse...

Dai wrote:Or get worse...

I was looking for an emoji involving a box of matches but couldnt find one.

Well there is a slight possibility I am an idiot. Today I noticed the earth wires from the injectors were not connected to the fuel rail mounting screw as they should be.

???? That's not on any of my bikes.

The injectors aren't directly earthed but have power directly to them and an earth pulse from the ECU to fire them. That earth may serve the ECU but I cant find anything in my circuits to confirm that.

Heres a pic - looks factory, is part of the injector wiring and was earthed on the fuel rail screw shown. No other place it could go from what I can see. Any suggestions?

Probably I'll just reconnect everything, put the tank back on and see what happens.

It is very definitely an earth and should be there but as to whether it is actually for the ECU I cant say. It usually is on a 10mm bolt directly to the head behind the fuel rail where the fairing mount also bolts.
Just had a good look it goes where the red arrow points.

Yes, that's definitely a ground.  The original post had me thinking you were talking about a wire coming from an injector connector.  I was thinking that it was something that a previous owner had added to work around a different problem.  Your photo shows a wire coming out of the harness, not an injector.

Back to square one.

RicK G wrote:It is very definitely an earth and should be there but as to whether it is actually for the ECU I cant say. It usually is on a 10mm bolt directly to the head behind the fuel rail where the fairing mount also bolts.
Just had a good look it goes where the red arrow points.

Yes I figured that. Since it goes into the engine wiring it may be that the fuel pump doesnt go without it so back to plan C and reconnect everything and see what happens.