Fuel gauge calibration

[Cougsfan]

if your under warranty - get those fuel sending units/floats replaced. My 2015, 3520H fuel sending unit went bad - heavy corrosion on the dang thing, clogging filters lines and the like

I did replace my sending unit under warranty. Didn't see a trace of corrosion on the old sending unit (seems weird something in a tank full of diesel would have a corrosion problem), mine just stopped working. Unfortunately the new one only works intermittently, but has the added feature of being much less accurate than the old one when it does choose to work Not the biggest problem in the world, but when I bought the tractor, the concept of having a fuel gauge did seemed to be a pretty upscale feature compared to what I was used to. So much for living in the 21st century

 

[Slowpoke Slim]

Lol.

I can understand that Cougs. At least on our tractors, you can look down in the tank with your eyeball, without having to climb up on the tractor. Small consolation I know, but it's something anyway.

 

[Hombre]

I did replace my sending unit under warranty. Didn't see a trace of corrosion on the old sending unit (seems weird something in a tank full of diesel would have a corrosion problem), mine just stopped working. Unfortunately the new one only works intermittently, but has the added feature of being much less accurate than the old one when it does choose to work Not the biggest problem in the world, but when I bought the tractor, the concept of having a fuel gauge did seemed to be a pretty upscale feature compared to what I was used to. So much for living in the 21st century

Gauge itself maybe????

 

[Hayloft]

Hmmmmm
Haven't inspected my sending unit yet but guess I am not too surprised to hear about the rust showing up. Saturation level for diesel (and hydraulic oil) has to be at least a couple hundred ppm and enough to encourage some rusting. A long time ago, an old guy who was even older than me shared this wise caution : Rust never sleeps.
I'm still looking at after-market sending units that might work in ole Nellie. Some of them are more rust-resistant than orhers. Anyway, just some thoughts.
Regards all

 

[Cougsfan]

Gauge itself maybe????

Maybe, but I doubt it. I suspect either loose connections somewhere in addition to the new sending unit being faulty. The system is pretty simple, The sending unity just changes the resistance, therefore the current flow sent to the gauge. The gauge is sort of like an ammeter. When it stops working completely (goes to past full or to empty) it has either lost its current supply or its ground (mine has been known to fail both ways, reading past full or reading empty) . I have tried adding a separate ground to no avail. The inaccuracy, on the other hand, probably has to do with the change of resistance is not consistent with the level in the tank, or possibly is not even repeatable to itself at different times (lousy potentiometer on the sending unit). All of the problems could all be just be a lousy quality sending unit (that is my best guess). If I was worried about it more I could hook up meters and check it out closer, but I am not that ambitious today as none of that is all that easy to do. In the mean time I will just fill the tank more frequently.