Fuel Gage Problems

Good afternoon all
So I am close to finishing up my 57 CJ5 project and I have everything working except the fuel gage? I have read a lot of the post and this seems a little different. Here is what I have:

When I turn on the ignition the fuel gage goes up but has a hard stop at about 1/8 of a tank no mater how much gas is in the tank.

I checked the ohms on the sending unit (new) and getting around 55 so I figured that should be close with the amount of gas in the tank.

I turned the ignition on and can move the float and the ohms change but the gage doesn’t change.

I checked the volts from the ignition wire to the jumper to the temp gage and it shows the same, that would tell me that the resister is bad an the fuel gage (new) needs to be replaced. The temp workers as it should as I had overheating issues and it registered as it should.

the reason I say this is different is when I ground the sending unit out it moves to the same spot quickly and than stops fast.

what am I missing or do I just need to go back and get a new fuel gage?

thanks again
Marty
1957 CJ5 with parts from 57 to 72.

 

What gauge are you using? Not all sending units and gauges operate using the same resistance.

 

This is a repo gage from Kaiser Willys. Here is what they say
Empty- 1/2 Tank- Full Tank-
73 ohms 23 ohms 10 ohms

 

There is a video on Youtube on how to check the sending unit.

Get some 16Ga wire. Run a ground wire from the battery to the sending unit ground. See what that does

 

Note on a card staying in. the Jeep when you fill the tank how much gas you put and the miles.
You refill the tank after 50 miles , you take note quantity\miles so you know approx when you have to refill next time looking at the odometer.
You keep a small can of gas in your Jeep in case ...
You forget the gauge.
So doing you will avoid to say to your wife, stopping on the side of the road : "darling, I believe that the tank is empty, let's walk a bit..."

 

So I tried the ground from the ground on the battery and same thing. Gage act strange if I ground the S wire it only goes to the same spot and stops. I hooked up a different gage and it worked going to fuel quick and back down slow.
Marty

 

If you can get the sending unit out of the tank. Build a box with one end open, the same height of your tank, put the sending unit in and move the arm up and down and see what the gauge does.

 

Thanks for the replies, I started pulling the gage cluster out last night and should be able to finish tonight. I think that Howard is correct that something wrong with the gage moving. I hope to find out tonight.

Steve, I had the sending unit out and it worked fine on an old gage cluster I pulled out.

Plan is to replace the old fuel gage out if I can’t figure out what is going on with the new one.

Marty

 

So tonight I took the whole cluster out of the Jeep. I took the cluster apart and hooked the fuel gage up independent of the cluster and I was able to get it to work. So I put the cluster back together and could not get it to work. Took apart again and gage worked when apart when I was putting back together I noticed the face of the speedometer was pushing down on the fuel gage and preventing it from registering. So when I started looking the cover glass and seal were not in correct. Once I rearranged and put back together it works great. Thanks as always for all of the help. One more thing off my list. LOL

thanks again
Marty
1957 CJ5 with parts from 57 to 72.