Fuel Guage

[jimraker]

I'm asking you smart guys for a tip on my fuel guage. It reads FULL from the minute I turn the car on. But it is not full (luckily I learned this only a few blocks from home....ooops). My question is: Is this something a garage tinkering fellow like myself can repair or does this need a shop? And where is it? I have a Fiat manual but no mention of this part. If there are instructions already posted on this forum, please point me in the right direction.

Thanks, Jim
1983 pininfarina in Maine

[rlux4]

Jim, the first thing that comes to mind is the sender, second is the float. You'll see the two wires going to them on the top of your fuel tank. Pull the assembly out and check the float for free movement. If it moves OK, check to see if the gauge is reacting. If it's not, sounds like the sender, which acts as a potentiometer.
Good luck.
Ron

[pope]

What happens on the fuel sender is, there are fine wires near the top that are wrapped in a continuous loop. There is a metal feeler that rides these wires and resistance changes depending on where it is thus changing the fuel gauge needle. This wire breaks after repeated use, and new ones cost under $40. Like Ron said, its on the top of the fuel tank in the trunk.

Good Luck

[mbouse]

the very first thing is to check the fuses, then the connections at the fuel sender, third, the connections at the gauge. Always assume no power first, other mechanical issues second. always assume a bad ground first when looking to electrical issues, and a blown/dirty/ or loose fuse second.

because the sender is a moving, mechanical object that will wear over time, it is a replacement item at some point in the vehicle's life. most vendors sell replacements at a reasonable cost.



i have a used fuel sender from my '80 that i replaced needlessly, if you are on a budget. $5 plus shipping.

[rlux4]

Mike, I think we didn't go the fuse route was because of the gauge getting power (goes up to full). If that's what it's doing, I assumed it was energized, just not getting the correct signal. Please don't tell me I could actually be wrong!
Ron

[jimraker]

Thanks for the answers! I agree its not likely power for the reasons mentioned and also I replaced every fuse "for good measure" a few weeks ago. I guess its time for me to learn how to access the fuel tank.... btw... can anyone suggest a book that actually shows what's what and where everything is on the car?

Jim

[mbouse]

if you are referring to a service manual or shop repair manual, i would suggest two:

Brooklands

and

IAP's Workshop Manual

[rlux4]

Jim, getting to the fuel tank is a snap. If you have the original carpet in the trunk, take it up. If you have the original 2 piece platform over the spare tire, take it up. The tire will be on the right side, the gas tank is on the left. You will see the two wires going to a removeable plate on the top of the tank. Take the nuts off the top of the plate, and carefully pry the plate up. Attached to the plate is the float assembly. Pull it out of the tank and you'll see the coil that pope talked about. Check it for obvious cracks, and if it looks OK, raise and lower the float while watching the fuel gauge to see if it is reacting. If your float has free movement, I'd check the potentiometer coil (coil of wire attached to the float) and the wire connections. When you get into it, you'll find that it's a pretty easy job.
Any questions when you're in it, bring em on.
Ron

[pope]

Hey, with the price of gas, why would you want it to read less than full! Now you'll have to fill it up every once in a while. I'd rather have a gauge that read full all the time.

[So Cal Mark]

before you go to the trouble of removing the sending unit, just disconnect the wires to it. Make sure they don't touch ground and turn the key on. If the gauge still reads full, the trouble is in the gauge or wiring to the sending unit

[mbouse]

thanks mark. that was what i intended with my suggestions. eliminate all the obvious variables first.