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How do I find a faulty ground?

So your saying that I am still looking for a possible break in the harness somewhere??

I do have a 2002 Touring service manual and there is a black ground wire for the sending unit in the tank. The tank itself does not need to be grounded. Can't imagine a 2002 Solftail is that much different

I would take a look at the fuel gauge wiring in the schematics. See if there is a ground wire amoung the wires in the wiring harness. In the late model schematics, black is used for grounds. Follow any black wires that you see in the fuel gauge or speedo and see if they go to the frame grounding studs. If there is a ground wire in the harness, you know that there must be a break in that wire.

If you can scan that one service manual page and upload it, I may be able to point you directly to the right area.
 
If you can scan that one service manual page and upload it, I may be able to point you directly to the right area.

I wasn't sure how to separate the PDF. The pages for my bike start on page 6-32. Let me know if these are the ones your referring to. These are 12 pages relating to the harness and other electrical components
 

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On the very 1st page at the top you will see the "fuel gauge" and "fuel level sending unit".
You will also see connector 117A / 117B. Note that pin 4 of connector 117 is a black wire. That's the ground wire. Follow that wire down and to the right and you will see that it terminates at GRD2 (stud Ground #2).

The fact there is a dedicated ground wire that runs between the tank sending unit and GRD2 tells you the fuel tank should not need to be grounded for the gauge to work.

What is strange is you have two problems. Performance issues along with gauge not working. Note that GRD1 supports the ignition system and GND2 supports the fuel gauge. It's not clear yet why that tank jumper would fix the running performance issues, but...

Start with fixing the fuel sending unit issue 1st. Either connector 117 is not making good contact, GRD2 has paint or something keeping it from making good contact, or the little black pigtail wire from 117A to the sending unit (and sending unit to float level) is broken. It probably is not the wire which goes from 117B to GRD2..(could be but would be remote)
 
On the very 1st page at the top you will see the "fuel gauge" and "fuel level sending unit".
You will also see connector 117A / 117B. Note that pin 4 of connector 117 is a black wire. That's the ground wire. Follow that wire down and to the right and you will see that it terminates at GRD2 (stud Ground #2).
I'm not sure if were on the same page. The very first page is for carbureted models. Mine is an EFI and the wiring is slightly different. My model starts on page 6-32. Im heading out to pull the tank and see what I can come up with.
 
Oops your EFI. OK

It will be easier to use page numbers on the PDF document (pp-1 to pp-21). Looking at page 18 of 21 (of the PDF document), the fuel gauge is connector 117A. The fuel pump/fuel level connector is 86A. Both have a black wire which is ground. Note that within the tank the fuel pump motor is also frame grounded for static spark suppression. That ground is not intended to carry any current. It just ties the tank to ground for static discharge.


Now look at the top of page 17 (of 21) and you will see BOTH 117B and 86B. Pin 4 of 117B and Pin 3 of 86B are both black wires. They are also Both ground wires. Follow both wires. They are tied together and then go to GRD3 (stud ground 3).

Therefore your problem is most likely one of the following.
1) Stud ground #3 is not making a good connection to frame ground. (paint,no star washer etc)
2) Connector 117 or 86 is not making good contact with its mate.
3) One of the pigtails coming off either tank device is broken. (117A or 86A to device)
 
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