fuel gauge

[WE b GPN]

i did a search and found some one had almost the same problem but the thread wasnt a whole conversation as in it wasnt finished. my fuel gauge is on empty all the time no matter how much fuel is in it ,untill i turn the lights on then it goes to the 3o'clock position. when the gauge is on E if i unplug the sending unit from the tank nothing happens it stays there. so i think its a ground problem but where should i start lookin first? is there a usual spot for the bad ground? THX

BTW its a 86 xj v-6 (NO LAUGHING it runs great)

[WE b GPN]

bump

[Nevada City Sparky]

Same problem here. Bump again.

Gonna check it out tonight on mine which has been newly rebuilt. In my case, I'm suspicious of the headlight switch, which feeds the instrument cluster with switched ground. Tested the switch last night and I may have a short on that terminal.

Searching myself before I go forth and tear more apart.

[Matthew Currie]

Check the ground at the sender. It may be attached, but it can corrode and make poor contact. Also check the ground of the gauge cluster. If you can't find a convenient way to check that, just add another ground line. It won't hurt and it might help.

edit: I'm guessing that the gauge is seeking ground through the cluster lights. Just curious, does anything change if you dim the instrument lights?

[jrock]

This probably isn't very helpful, but I took my gauge cluster apart and sprayed the inside of the blue plastic housing with chrome paint to improve the gauge lighting, and I apparently sprayed some on the connector for the plug. When I turned on my lights, it cause my temp gauge to slowing creep toward max. Cleaning the connector fixed this. Not sure where I'm going with this, just wanted to share a similar experience. I would agree with Matthew Currie as I had problems with my turn signals that were caused by things seeking other grounds when their own had failed.

[Nevada City Sparky]

This probably isn't very helpful, but I took my gauge cluster apart and sprayed the inside of the blue plastic housing with chrome paint to improve the gauge lighting, and I apparently sprayed some on the connector for the plug. When I turned on my lights, it cause my temp gauge to slowing creep toward max. Cleaning the connector fixed this. Not sure where I'm going with this, just wanted to share a similar experience. I would agree with Matthew Currie as I had problems with my turn signals that were caused by things seeking other grounds when their own had failed.
I'm thinking that may be where my problem is. I'll check the ground from instrument cluster, since my gauge PEGS at 3 O'clock as soon as I start it up and when I hit the headlight it screws up the turn signals (indicator lights glow)

[ltkaknm]

I had similar problems recently and I found out that the plastic housing of the sending unit had detached from the rest of the fuel pump assembly. Oddly enough sometimes I would get wild readings as the connection was being made and then back to 3'o clock.

LTK