Fuel gauge issue
 

A while back I replaced the sender, and all was working well. Other day, the battery died. After jumping, the fuel gauge read 1/4 tank (it was over 3/4).

Shut it off, on the next restart, the gauge read empty and has stayed there.

I unhooked the wire to the sender, gauge went past full (way past).
Unhooked tan wire at fuse box, same thing.

Checked voltage at the box where the tan wire goes, 7.8. Test light lights, but dim. Is this supposed to be less than 12?

Ran a new wire from fuse box to sender, and the same thing happened, so I think that wire is ok.

All fuses seem ok (does anyone know which fuse controls this? I can't read anything on the old box.

So what is the next test?

thanx

Re: Fuel gauge issue
 

Pulled the sender. If I move it up and down, the gauge moves.

Sender appears undamaged, float looks undamaged, not full of gas. I looks like it is installed correctly.

But when I put it back in the tank, the gauge still goes to empty.

Re: Fuel gauge issue
 

Took sender out and grounded it. hooked up a wire from post to the sender wire, moved float, and it appeared to work correctly.

Put sender in bath full of water, float worked.

Cool bubbles came up. Shook float, heard liquid inside. Hmm, looks like a cracked float. I think I got my culprit.

Bummer.

Thanx for all the help. No, that's not sarcasm. This place is great, and all this happened in a few minutes, did not expect an answer that fast. But it was
kinda like bouncing stuff off of friends anyway :)

Re: Fuel gauge issue
 

Anyone know where to find just the float? I can't seem to locate it.

thanx

Re: Fuel gauge issue
 

I don't want you stuck here just talking to yourself! I see in the LMC catalog they have the float. What is your float made of?

Re: Fuel gauge issue
 

I went thru this when I first bought my truck in 2006.
I bought the float from LMC and installed it in the original sender. My gauge still read empty.
Ened up the LMC float woulf float when I tested in water, but sank in gas. LMC float was heavier than stock float.
I ended up finding and soldering the pinhole in the original float, and it has worked since.

Re: Fuel gauge issue
 

I do that a lot :) It's brass.

I found this float and ordered it.

https://www.classicparts.com/1947-72...ctinfo/23-575/

6.00 = 10.00 shipping. Steep, but I could not find it locally and it' cheaper than the sender.

@oldgold. I hope I'm luckier than you. I had thought about repairing it, has a long very tiny crack and I thought I would change the weight and make it read incorrectly. If the new one does not work, that is what I will try next.

Re: Fuel gauge issue
 

I don't think soldering it would change the buoyancy of it significantly, even if you used a lot of solder. But getting a new high quality metal one is even better and that's not a bad price delivered. I'm going to bookmark that link in case I need one in the future.

Re: Fuel gauge issue
 

I have two questions.

Did the float still float even when you heard some gas sloshing in it? The float is not going to sink from 3/4 tank to 1/4 tank unless it is full of gas and then I think it would hit bottom.

Second, have you tested the resistor? Pull the resistor from the back of the fuel gauge and test it. It should read in the area of 85-90 ohms. If it is anything less, such as 25 ohms, your resistor is bad. It is one of the more common reasons why a fuel gauge will not go past 1/4 full regardless of full level.

Re: Fuel gauge issue
 

The tank was reading empty. When I removed the float and moved it up and down, the gauge went from empty and back. The sender is only 6 months or so old, I think it progressively filled up enough to make it sink.

I had it sitting on a towel that go wet from gas when I unhooked the fuel line, so I'm hoping enough leaked out to make it float in the tub. The bubbles told me that it was filling with water, but very slowly.

So I won't know for sure until I get the new one. Hoping this fixes it.

Re: Fuel gauge issue
 

New one fixed it.

thanx for input.