Adjusting Fuel Gauge

The fuel gauge works fine except that it reads wrong. Recently it was at the E , but when I went top fill it with non-ethanol gas before taking him to the mountains, it only took 5 gals. I’ve noticed this before that it drops from full fairly quick and goes below empty for ever. Is it possible to bend the float arm to adjust this?

 

I'd suppose so.

Not an expert here, but first I'd check every electrical connection in the circuit to eliminate any possible resistance and ensure true gauge values. Including grounds. Might also check that the instrument cluster voltage regulator is calibrated correctly.

 

Mine had tabs that limited travel of the float arm in either direction.

 

You will have to bend the wire the float is on. Adjust float height when empty and full, which means pull sending unit.

 

Yes.

Pull the sender and measure the depth of the tank. Adjust the float arm so that you reach the stop on the sender and the depth you want at the same time. The sender should ohm-out when empty at the spec gioven in your FSM. Adjust the top stop so the arm is all the way up and not touching the bottom of the tank.

Shake the float to make sure it's not partially flooded.

Note this is not a precision instrument. Likely you can make it better by adjusting. You can also test that you get a full-half-empty reading at the proper position of the float.

 

i have the same issue. I call it the "60 mile tank". It would sit at full for 60 miles or so, then drop like a rock until it hit "E", then it would only take about 6 or 7 gals to fill. So i adjusted the bend in the float and tabs. So now it still sits at full for miles, but i have a more accurate indication when it gets to "E". Gives me about a 2 gal reserve. I always write down my mileage at fillup as a backup. What i did for adjusting was to get the tank down to a couple of gallons, then bend the float arm to where i wanted it to read on the gauge. I would make an adjustment, then hold it flat in it's position, and re-adjust it to where I wanted.....no need to screw it down each time. Make sure you keep the grounding wire attached.

 

My main things is the E being closer. I replaced the float back in 2015 because it was liquid logged and it looked like bending was an option. But I was curious if others had done that or if there was another method. So as run this tank down, I’ll get it close then drain it totally and measure exactly 2 gallons, put it in and then adjust the float. Thanks for input.

 

x2

 

Yes but I could use a high quality bandaid. So I’m guessing get a reading at full then run to empty and read?

 

Or just siphon it. Even less time.

 

It will still boil down to adjusting the float arm if you want to adjust for "E". I'm sure these units are adjusted for "in the ballpark" from the factory. All you'll be doing is fine tuning it for your vehicle. No harm, no foul......

 

I know from my personal experience that adjusting the float arm does work for setting the "empty" point on the gauge. Just as the OP stated...mine was/is the same way. That's how my current system works. I've done the resistance readings, and I've also made sure that the gauges(2) and senders(3) were compatible. So...although I don't get any needle movement until I've gone 60-70 miles, I at least have my gauge calibrated so when it hits "E", I know I have roughly 2 gals left. I know how much fuel I have when I start.....I want to know how much I have close to empty. Remember, we're working with primitive instruments here....LOL.

 

They worked okay in 1955. Perhaps I'd use the word "simple."

If the range can only be accurate at one extreme, and the electrical aspects are correct, my guess is that a generic float arm is not the right length for the Jeep tank.

In other words the radius of the quadrant it describes does not match the height of the tank. I would try to correct the "length" of the arm to allow its full swing, not just bending it to coincide with "empty."

 

If I recall the trick to bending the float arm is the opposite of the direction you want to go.
Up is down and down is up....or something similar.