Hello to all: Been awhile so I hope all is well with you guys. I've run outa gas twice now. The shop I use has installed 3 new gauges & all of them failed. Two from KaiserWillys and one was an aftermarket. The head mechanic told me I'll never get a true reading anyway unless I was stopped & on relatively level ground cuz my gas tank has no baffling. Probably is truth to that or is there?.  Now i'm curious, cuz when Full it reads way over the F mark. It showed about half-full when I ran out. I wonder if the needle or perhaps the gauge itself could be tweaked (needle moved back or gauge re-calibrated in some way or the float?). Or r 3A's notorious for this? Could it b a wiring problem. I know some of u have been there too, so I would definitely like to hear what u guys think I should do next. Ty  Ty

I agree that a sender in a '3A tank will never be terribly accurate, and it also might be a little jumpy since fuel will slosh around, (I think there is at least one baffle in there) but I think there is no reason that you can't get a reasonably decent working sender/gauge combo.

The original CJ3A fuel gauges were, I believe, a balanced coil design which I think are quite sensitive to source voltage. I'm thinking that new gauges are also of the balanced coil design. Does your replacement gauge voltage needs match what you're running in your Jeep now? (6V or 12V?) I wonder if that's the root of the problem; mismatched voltage needs for the gauge and sender.

Here's what I would do: take out your sender and gauge, and set it all up on a bench with a power supply, or lacking that, use a bunch of double A batteries in series to mimic what your Jeep runs now. Connect the power to your gauge and wire the sender output to the gauge, and be sure to also ground the "case" of the sender to the negative of the battery pack as well. When the sender is hanging down, the gauge should read "E" within reason, and when you push the sender arm up, the gauge should go up to "F".

(If the gauge doesn't move at all, suspect something is not connected right.)

If you get 1/2 full when the sender is hanging all the way down, either the voltage rating of the gauge is not appropriate, or the resistance of the sender is wrong. Change the voltage to see if you can get it to go to "E" with the sender hanging down. (this is where having a bench top adjustable power supply would be helpful). Let us know what voltage your Jeep and gauge are....

No tweaking of the gauge,float, or sending unit has worked. It still won't read correctly. It's all 12V. The shop is now talking about just getting a new tank (poly, they suggest) with matching gauge,sending unit alrdy installed. I only c Omix having that but I've heard negative comments on Omix products. Any other suggestions?

My gauge I purchased from KW had an issue and when I called them I was told to run a second ground. Not sure what you have but does your in dash gauge have 3 poles or just 2? The one I purchased form KW had 3 and until I added the second ground it was a bit squirrelly.

A stick never fails...