Fuel Gauge question...again

aaluck · Oct 9, 2019

I have a L4400HST. The fuel gauge is stuck on full when ON and empty whenever OFF..

I pulled both wires off of the sensor and the tank stayed FULL. Touched the wires together and the gauge goes to EMPTY. Apart again...FULL, over and over. From what I can gather this means the problem is NOT with the sending unit.

That being said what is the problem and more importantly how do I fix it!!! (Sorry the question mark does not work on this keyboard).

lunasdude · Oct 9, 2019

aaluck said:
I have a L4400HST. The fuel gauge is stuck on full when ON and empty whenever OFF..

I pulled both wires off of the sensor and the tank stayed FULL. Touched the wires together and the gauge goes to EMPTY. Apart again...FULL, over and over. From what I can gather this means the problem is NOT with the sending unit.

That being said what is the problem and more importantly how do I fix it!!! (Sorry the question mark does not work on this keyboard).

Could be (if you're sure it's not the sending unit) the float.
OR could be a wiring issue such as a short etc.
I would start there, trace wires from the sending unit to the dash make sure no breaks etc.
Then I would check the float, then the sending unit again.

The first solution is free, the second $ the third $$.

Hope that helps!

North Idaho Wolfman · Oct 9, 2019

aaluck said:
I have a L4400HST. The fuel gauge is stuck on full when ON and empty whenever OFF..

I pulled both wires off of the sensor and the tank stayed FULL. Touched the wires together and the gauge goes to EMPTY. Apart again...FULL, over and over. From what I can gather this means the problem is NOT with the sending unit.

That being said what is the problem and more importantly how do I fix it!!! (Sorry the question mark does not work on this keyboard).

You've got it backwards, your results of touching the wires together and the gauge moving 100% means it's got a bad sending unit!

Mark 99 · Oct 10, 2019

I don't know if this applies to your situation but my 3901 had an issue and after parts, troubleshooting, and time I got to the bottom of it. The gauge would not come off the full mark until the tank was over half empty. I discovered the tank was engineered this way. The top of the tank is several inches above where the sending unit mounts so by design that's all that can happen. I believe it was an engineering trade off to be able to stuff a large enough fuel capacity in a very limited space. Pull sending unit attach wire put through range of motion and see if gauge follows.

aaluck · Oct 10, 2019

You are correct. I had it opposite of what it was and checked again last night. Open=empty, closed=full.

I ordered a generic Bosch sending unit on Amazon for $16.00 (used, like new) and will see if it works. If not, may bite the bullet and spend the $90.00 for the Kubota one

sdkidaho · Oct 24, 2019

This is definitely helpful. I'm glad there are others experiencing the same issues - not that I'm glad you're having trouble but that I can find some help.

aaluck · Jan 8, 2020

Quick update.

It turns out that I busted knuckles, contorted my arms and legs trying to reach everything for nothing. The gauge was actually "working". It appears that it must fall below almost 1/2 tank of fuel for the gauge to actually move. Not sure why, but that's how mine works.

dlsmith · Jan 8, 2020

Fuel gauges and politicians can be believed to be correct about the same amount of the time. Rarely if ever, and mostly be accident.

SidecarFlip · Jan 8, 2020

I really dislike fuel gauges in general. Last tractor I had, the gauge quit and I used a wood stick to check the level......

GeoHorn · Jan 9, 2020

SidecarFlip said:
I really dislike fuel gauges in general. Last tractor I had, the gauge quit and I used a wood stick to check the level......

We never trust fuel gauges in airplanes. Dipsticks are used when accuracy is necessary. (Fuel does not determine distance or work-accomplished. It only equates to time-in-service.)

Ive determined that in the average useage to which I put my tractor, compactor, RTV, etc., Im burning about X gals/hr. Its a simple matter to note the time on my watch or hour-meter to know about how much fuel is remaining. I keep a log of how/when I use my tractor and what I accomplished during that time. Makes interesting reading months down the road, and has been especially useful when trying to recall when I did such-and-such or performed certain maintenance.

Just a suggestion. Hope it helps.

Roadworthy · Jan 9, 2020

There is a float somewhere inside your fuel tank. It could be sticking rather than traveling smoothly down as the fuel level drops. I have no idea how accessible it is in your tractor but I think you'll find your problem there.

GreensvilleJay · Jan 9, 2020

I set the one in my diesel forklift to say 'empty' when really 1/4 full. If you've ever run a diesel out of fuel you KNOW why !

angelo c · Jan 9, 2020

GeoHorn said:
We never trust fuel gauges in airplanes. Dipsticks are used when accuracy is necessary. (Fuel does not determine distance or work-accomplished. It only equates to time-in-service.)

Ive determined that in the average useage to which I put my tractor, compactor, RTV, etc., Im burning about X gals/hr. Its a simple matter to note the time on my watch or hour-meter to know about how much fuel is remaining. I keep a log of how/when I use my tractor and what I accomplished during that time. Makes interesting reading months down the road, and has been especially useful when trying to recall when I did such-and-such or performed certain maintenance.

Just a suggestion. Hope it helps.

I got a few hours in a C182m with bags in the tanks...boy were they fun to watch on a long ride....only ever "coughed" when we were on T/O or over water....then the "wrinkles" would let the water loose.....fun.

GeoHorn · Jan 11, 2020

angelo c said:
I got a few hours in a C182m with bags in the tanks...boy were they fun to watch on a long ride....only ever "coughed" when we were on T/O or over water....then the "wrinkles" would let the water loose.....fun.

LOL. Yep, and anytime youre flying and notice that you are making fuel (increasing or stopped decreasing fuel indications) are a sign of a blocked fuel vent. (The bladder-tank is collapsing.) Mud daubers did that to me once in my Baron. Went-around one night to avoid deer on my grass runway and just as I pulled up the right engine quit!

The pump simply couldnt suck enough for the increased-power of the go-around.
(Sorry for the hi-jack.). (Thats an aeronautical term too!).

aaluck · Jan 13, 2020

Roadworthy said:
There is a float somewhere inside your fuel tank. It could be sticking rather than traveling smoothly down as the fuel level drops. I have no idea how accessible it is in your tractor but I think you'll find your problem there.

That's what I originally thought but I removed it completely and it is smooth and without any issues. After I reinstalled it I can push it down gently with a stick and it returns to the top of the fuel.

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Fuel Gauge question...again

aaluck

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lunasdude

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North Idaho Wolfman

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Mark 99

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sdkidaho

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