Fuel sender
 

Just checking in with those that have more experience that me.
My fuel gauge doesnt seem all that reliable. I bought a new fuel sending unit from brothers and installed it. My fuel gauge shows about 3/4 full when really full and when. Its at 1/4 left I can only get 10 gallons into the tank.

I assume it's a bad fuel sending unit? Or anything else I should check first?
I may just live with the issue for a while but wanted to check with the experienced folks first.

Its a bone stock 72 GMC Jimmy.

Re: Fuel sender
 

I could be wrong but i think some sending units have the wrong ohms (newer trucks were different than 67-72s) so the gauge never reads right. Try searching "fuel sender ohm" for some fun reading.

This might be real helpful: https://67-72chevytrucks.com/vboard/...d.php?t=640615

I bought my sender from classicheartbeat - haven't used it yet, but i trust them more than brothers.

good luck!

Re: Fuel sender
 

So i may have a 0-50ohm variable resistor in my fuel sender instead of a 0-90ohms resistor?

That would suck, but at least i know.

There is no one who has built a voltage to current mirror circuit to adjust the currents to similar levels as a 0-90ohm resistance circuit?
That seems like it would be relatively easy to do and its just a couple of transistors.

Its been 35 years since i last calculated an voltage following current mirror so if someone has a working circuit i would be happy to borrow it... anyone?