[retromopar]

hello all,
I have been trying to sort out issues with my gauges and at a lost what to do. Both my fuel and temp gauge were dead. I traced the problem to the voltage limiter, and replaced it with a solid state one, now I have constant 5 volts. My replacement temp gauge is now working, but the new fuel gauge is pegged at full. I pulled the wire off the sender by no change, I then disconnected the sender, (purple) lead from the gauge and nothing happened. I then grounded the purple terminal to the frame and still it reads full. I don't know what else other than a bad gauge it can be. Any Ideas? The gauge came used off E-bay.

[Adrian Worman]

If the gauge needle jumps straight to full when the sender wire is put to a ground then the gauge should be good. The sender just provides more or less ground resistance as it moves up & down so when the tank is full & the sender float is pushed to the top of the tank it gives a 'total ground'.

So, if the gauge moved up quite smartly when it's got a good ground then you could assume it's working fine.
If it's reading full even when no power is put to it then it's screwed .
That leaves a problem elsewhere, so check the sender isn't stuck, check the wire from the sender back to the gauge thoroughly, could be a trapped or frayed wire somewhere?

Be warned though, if you ground out the gauge for long you'll fry it.

[fbernard]

If you disconnect all wires from the gauge except the power source (voltage regulator), it shouldn't react (or barely move a little bit off from the bottom) when you turn the key to 'On'.
If it does, it's shorted internally.
It may be just a wire touching the frame inside the gauge, it's a simple galvanometer.
I'm not sure it's serviceable though.

[cv70chall]

Is the grounding strap on the tank for the sender?

[retromopar]

Stupid me!
One of the mounting posts on the gauge was touching the dash housing. I insulated the cut outs and remounted the gauge. That brought the gauge to 1/4 full. I removed the sender and moved it through its range, it reads full, half or almost empty. Too many dead spots so I ordered a replacement. Thanks for all the quick responses, slowly getting the electrical gremlins sorted out.

[cv70chall]

Glad you got it sorted!