fuel gauge

[tn trooper]

Hey guys, my fuel gauge in my 85 CJ7 isn't right. When I fill it up the gauge only goes to 3/4 of a tank. I replace the sending unit in the tank today, and when I filled it up the same thing again only 3/4 tank. Could it be the gauge itself it is the one that came in it what else could it be???????

 

[priceg]

Unplug the sender connector at the sender and ground it. Not sure what color the wire is. With the sender wire grounded, the gauge should sweep completely to full. If it does not, it is the gauge.

 

[54cj3b]

is the gauge in speedo cluster there know to stick ,
blow some can air in it to blow out any dirt or debrie
the spring the needle is attached may have got caught up on

 

[gert]

Yep the gauges run on low voltage and your fuel gauge runs on a variable ground so all that mud you have caked on everything does not help point being make sure you have a good ground at the sending unit a good connection to the sending unit and the same for the gauge ,and I like 54cj3b's answer to clean out your gauge