L3560 Fuel gauge stays on full

[BBFarmer]

As the title suggests, The fuel gauge in my L3560 seems to be staying on full.

I say "seems" because I drove her to my shop (almost 9 miles from our farm) for a service a few weeks ago. She ate about a quarter of a tank. Hit up the gas station right next to the shop before heading home and filled her to the brim (which i never do). Usually, once it hits E, i'll put 10 gallons in her and it will come up to full......however "full" that actually is I do not know. I think its a 14 gallon tank either way.

Anyways, drove home, parked her- still on full.

Couple of weeks ago ended up helping the neighbor push some limbs for about 20 or 30 minutes, finished up- still on full

Last week, cut about 3 or 4 acres around our blueberries....maybe 45 mins or so- still on full

Then yesterday, had my youngin knock the top off our back 40 one last time. He text me (I have him check fluids and fuel before he uses anything on the farm) "Dad, tractors good and full of fuel." Then I said, "dammit". lol

So I reckon, somethings up.

The gauge sweeps when the key is cycled, however it goes right to full. Almost too full.....as in, open circuited kind of full lol.

If, and big IF, this was in the automotive world, this would be nothing more than a basic variable resistor. And generally speaking, if a signal wire goes open, the ciruit would read high (a high ohms reading, 100,, 200ohms etc...), resulting in a low reading on the gauge. Or if the ground side goes open (although it too is opening the signal circuit) this is commonly interpreted through instrument cluster circuitry as a low ohm reading, resulting in the gauge reading full. Or possibly in this case, swinging the needle its maximum range just above full.

So short story long, am i right in thinking - low ohms= full tank, high ohms= empty tank.

I did hit some pretty violent bumps coming home and maybe could've damaged the float.

But being the gauge still sweeps when the key is cycled (unless that's just basic logic for the cluster) ALMOST rules out power or ground issues.

Also, seeing that the top of the sending unit is about 1.5 inches from the bottom of the cab, i'm scared to ask what the r&r is. Tank comes out or cab comes up? I'm ready for either lol.

Any tips, tricks, or suggestions from my fellow kubota brethren is greatly appreciated.

Brandon

 

[Bmyers]

My L3560 is the same. I can run it for several weekends and it stays on full, then quickly starts moving towards empty (learned that when I first got the tractor).

So, I have just gotten in the habit of filling my tractor up after each use. It keeps the tractor ready to go, helps reduce the space that will allow for condensation.

 

[North Idaho Wolfman]

Sounds like the sending unit has stuck in full, can happen if it has rust on the linkage then filled where it wedges in the rust.
Other option is a grounding issue to the sending unit.
The gauge moving up and down is normal even with a stuck sending unit or missing ground.
If you can get to the sending unit use a wire to ground the body of the unit and see if gauge moves, if it does bad ground.
Then ground the sensor wire, if the gauge moves then bad sending unit.

 

[BBFarmer]

My L3560 is the same. I can run it for several weekends and it stays on full, then quickly starts moving towards empty (learned that when I first got the tractor).

So, I have just gotten in the habit of filling my tractor up after each use. It keeps the tractor ready to go, helps reduce the space that will allow for condensation.

Yes sir, I get what you're saying.

I've had this one since March. Did notice initially, unlike my 3301, it does favor the full side for most of the tank, then falls quickly....kinda like an old chevrolet.

I figured this was probably due to the saddle tank design the grand L's carry.

However, my initial indication of a problem was it took me a quarter tank to get from farm to shop, but remained on full for the ride back from shop to farm.

And although this was the first time for her to get filled at the pump ( of which i filled to the brim), I would've thought it would've came down by now....but maybe not.

If you can get to the sending unit

How does one do this? I downloaded the wsm but have not found an r&r procedure yet.

They do have a side picture of it with the steps and what not removed for testing the circuit. Guess i'll just have to see what they've removed when I get home tonight.

Thank you so much for y'alls responses.

 

[Firstgear]

My reads what I would consider normal. About right all the time. My tractor was purchased new in April ‘23.

 

[Fastball714]

I have a L4060 and fill it up to the top of the neck. It takes a while to use enough fuel to get gauge to move off full. I think yours is normal.
Why don't you top off the fuel to see how much it takes?

 

[GreensvilleJay]

Your thinking of how the gauge and sensor work ( auto and tractor) is in error.
Yes, both use a low value variable resistor as the sensor which is connected to the 'low' side of the gauge.

=12---> VR-->gauge------>sensor----> ground
This has been the way 'forever' almost.

When tank is empty, sensor is high resistance, small current, meter shoes 'low'
When tank is full, sensor is low resistance, high current, meter shows 'full'.
Most sensors are 200-300 ohms, nonlinear and while the range of resistance is say 0-300 ohms, actual high to low range will be say 50-250 ohms.
Presumably it was done this configuration so theat when the sensor wire got grounded to the vehicle's frame 'sparks don't fly', meter says 'full' or 'over full', easy to diagnose and repair.

quiktest. If you ground the sensor wire at the tank, and the gauge read 'full', you have a sensor problem.
If the gauge always reads 'lowish', check the float cork. if it's real cork, it's 'put on weight'.

 

[BBFarmer]

My apologies fellas. I should have followed up on this. Definitely jumped the gun a bit.

I did end up filling her back to the brim in which she only held 4.5 gallons or so.

Between me losing track of how long she'd been sitting, and also my oldest filling her up at the neighbors after a day of helping him, it looks like everything is fine.

I wasn't running her till the low indicator and I was just always used to dumping 2 jugs in her and it coming up to full.....been short changin the ole girl this whole time....im an idiot.

I do however, greatly appreciate y'alls responses.

Your thinking of how the gauge and sensor work ( auto and tractor) is in error.

I think during my brain damaging incoherent rambling I probably only created confusion lol.

Basically, full gauge low ohms low gauge high ohms is what i was trying to spit out.

if a signal wire goes open, the ciruit would read high (a high ohms reading, 100,, 200ohms etc...), resulting in a low reading on the gauge. Or low ohm reading, resulting in the gauge reading full. Or possibly in this case, swinging the needle its maximum range just above full.

So short story long, am i right in thinking - low ohms= full tank, high ohms= empty tank.

My thinking is correct although my wording may not be.

With that said, with much respect, i do know who im talking to among the others here. And that, in most cases, yall's expeirence more than doubles my measley 25 years. I am from the era of always respecting my elders.