1964 k10 gas guage problem

[cameyer]

I am new to this board and just recently purchased a 1964 k10 pickup as my first car. I am slowly going through it and getting everything working. When i first bought the truck i didn't know the gas gauge didn't work till i ran out of gas just 5 min away from the sellers house. I've been searching through this form and have followed everyone's advice on what to do to check it however have hit a wall and don't know where to go from here. so far the gas gauge only reads full with everything hooked up, I then disconnected the ground wire which i read should cause the gauge to read empty but the gauge still reads full, i think hooked the ground back up and disconnected the lead wire from the sending unit and the gauge still read full. the gauge is at empty when the truck is off but always reads full when running. someone please help me where do i go from here

[FetchMeAPepsi]

I had this happen with a gauge that a buddy of mine spun when I had it off. He spun it around a few times back and fourth and after that it wouldn't read right anytime it was hooked up. Always read full if the engine was on.
I ended up having to buy a new gauge. I tinkered with it forever before breaking down and shelling out for a new one but never got it reset.

9 times out of 10 it's a sending unit issue. 1 time out of 10 it's a buddy spinning the dial when you're elbow deep in an engine rebuild.

[cameyer]

thanks for the info! so do you think my gauge is busted? or should I start by checking out the sending unit?

[FetchMeAPepsi]

Checking the sending unit is free so I'd start there

[rockdogg2020]

Check the sending unit, easy to do. If you have a DMM use it to check the resistance. Or just move the float up and down to see if the gauge moves. Then go from there, it's a this or that process
Posted via Mobile Device

[rockdogg2020]

My gas gauge, nor my speed gauge worked when I first got my truck
Posted via Mobile Device

[DoubleL]

Originally Posted by rockdogg2020

My gas gauge, nor my speed gauge worked when I first got my truck
Posted via Mobile Device

LOL! I'm in the same boat. You better fill up often! Kinda hard to keep track with neither.

[rockdogg2020]

Lol, I kept 3 gallons on back of the truck and used a GPS for speed. But they work now. Had a broken speedo cable and bad sending unit. PO didn't even leave the sending wire had to order that too
Posted via Mobile Device

[64thunder]

mine is the same but even when i turn the truck off it reads full if i increase resistance on the circuit it drops might be your float thats causing it