Fuel gauge not working properly

[sbct]

Hi folks,

I have an XJ2025h with only 40 hours on it. Fuel gauge is staying just above empty even though I filled the tank almost full with 5 gallons of diesel fuel. Anyone have any ideas of what the problem may be? Gauge acts like it is working and goes up a little when you turn the key on so its getting some sort of input from the sending unit. Gauge just reads like there is 0.5 gallons of fuel left in the tank when there is actually about 5.5 gallons in there. Gauge was working fine before my most recent fill up. Only thing I did different was I refilled the tank while the tractor was running.

Anyone have any ideas what the problem may be? I would think if the sending unit went out the gauge would read zero instead of just the low reading its giving me?

Thanks in advance for your help and input.

 

[bruceatlam]

I actually don't have any idea since I don't know how your tank is set up, but in my case, I had erratic fuel gage behavior. My level sensor is a float inside the tank that pivots around a center point and raises and lowers in the tank as it pivots. The float is mounted to an extended arm with a few bends in it. The float is mounted to one end of the arm and the center pivot is the other end; the center pivoting end is mounted to the outside top of the tank with several screws. In my case, the float was binding on the inside surface of the tank as it raised and lowered. I pulled the assembly out of the tank and made a few tweaks in the arm to move it away from the side of the tank and all has been well since I performed that minor surgery.

 

[sbct]

Thanks for the ideas. As soon as it stops raining I will go out there and check it out and see if my setup is similar.

 

[beowulf]

I had my fuel gauge stop working once and discovered mice had chewed through the wire running from the in-the-tank gauge to the dash indicator. I patched the wire, put a bag of mothballs nearby and never had a problem again. But you are getting some kind of reading at times so that may not be the problem - unless a well worn or chewed on wire is just intermittently connecting. Anyway, look for simple explanations first, and that to me would be to check the wires.

 

[sbct]

Last night before I went to bed I prayed to the tractor gods to fix my fuel gauge. Guess what? This morning I fired her up and the fuel gauge is working perfectly. I turned it off and on several times throughout the day and it worked perfect every time. No idea why the fuel gauge decided to take two weeks of vacation but thankfully she is back.

Absolutely only thing I can think of and this is kind of a stretch but I think I have a bad battery connection somewhere. Every once in a while I will go turn the key and I will loose all power like the battery is dead and the load from the starter zaps all the juice turning the gauges and lights off. I usually just pop the hood and wiggle the battery cables and the lights come back on and she then fires right up like nothing ever happened. I wonder if the fluctuating power/voltage was playing games with my gauge? Just a guess...

 

[RNeumann]

The sending unit adjusts resistance as the level changes. Occasionally they will get a bad "spot" and won't read correctly. It will either give false readings all the time, only while it is at a given level or won't read at all.


One of my vehicles goes from full to just above half in about 2 gallons. It then stays there until the fuel drops another gallon or so and returns to normal operation. Started doing that about 10 years ago.....one day I'll fix it.

Yes the bad connections can/will cause interesting issues. Especially if it's a ground.

 

[PJSprog]

There have been some issues in the past with poor ground connections due to paint. You might check that.

Intermittent problems are the worst.

 

[PILOON]

"Intermittent problems are the worst. "

For sure, we told clients to bring it back when it stops or breaks.

Other than that you need a VERY detailed description of circumstances that lead up to the condition.
In aviation things like a faulty magneto or shot diode in an alternator could cause errors or even malfunction in navigation instruments.
Conversely a radio transmission at certain frequencies could result in wild RPM readings on a tachometer.

I can just imagine the nightmare testing today's new aircraft with all their 'fly by wire' systems.
Everything has to be tested against everything in every configuration and all over again if any change or mod is made.

It is all called EMI and RFI.

 

[George2615]

Check your ground cable from the battery where it connects to the metal. A bolt fastens the terminal end to ground just below the battery and it needs to be clean. I removed my bolt, wire brushed then added anti seize to the threads, and scraped the paint off the mating surface when I first got my tractor. I did not have any problems beforehand but did on previous tractors in the same area. I also cleaned the battery + terminal on the starter and applied some grease to prevent corrosion.

 

[sbct]

Check your ground cable from the battery where it connects to the metal. A bolt fastens the terminal end to ground just below the battery and it needs to be clean. I removed my bolt, wire brushed then added anti seize to the threads, and scraped the paint off the mating surface when I first got my tractor. I did not have any problems beforehand but did on previous tractors in the same area. I also cleaned the battery + terminal on the starter and applied some grease to prevent corrosion.

Symptoms make me think you are 100% correct. I'll get out there today or tomorrow and do exactly that.