Oil & Fuel Fuel Gage Stuck on "F"

Acolar · May 21, 2009

Took delivery of my new 2009 model year 3520 w/CAB - fuel gage worked well as it began its decent to empty while mowing ponds. Went to the fuel station to fill up on diesel, gage went to full. Next afternoon spent another 4 hours mowing ponds and fuel gage did not move off "F".

I have search many threads on this topic but have not identified any posts with technically rich content that provided any diagnosis or root cause on recent feul gage issues.

Awaiting my CD parts/service manuals. Any suggestions would be appreciated.

Thanks

Tony

nmu98 · May 21, 2009

I am not sure any of us with the problem have a technical answer other than the 3x20 series with a cab stay on full for a long time and then when they move, they go down very fast. I was tilling last night and in 30 minutes went from a 1/2 tank to less than a 1/4.

You just get used to it.

Cidertom · May 21, 2009

On the 4300 I had, I could hit the float with the nozzle of a commercial pump. This would cause it to stick. I would have to fish around with a stiff wire to get it free again.

ToadHill · May 21, 2009

I think you got the new experimental model that they have been working on to meet the governments new CAFE standards.

Spudland_Dave · May 21, 2009

nmu98 said:
I am not sure any of us with the problem have a technical answer other than the 3x20 series with a cab stay on full for a long time and then when they move, they go down very fast. I was tilling last night and in 30 minutes went from a 1/2 tank to less than a 1/4.

You just get used to it.

Exactly correct...not a "Problem" per se, if you look at the shape & design of the tank you can see theres alot more volume at the top of the tank..

sunnyside360 · May 21, 2009

nmu98 said:
I am not sure any of us with the problem have a technical answer other than the 3x20 series with a cab stay on full for a long time and then when they move, they go down very fast. I was tilling last night and in 30 minutes went from a 1/2 tank to less than a 1/4.

You just get used to it.

Ditto!! Fuel gage on my 3720 cab tractor has behaved exactly as nmu98 described above since it was new.

mfreund · May 21, 2009

I would blame the ULS diesel fuel!! Try to find Ag diesel.

Acolar · May 22, 2009

Thanks guys - great points, I am tending to believe the shape/geometry of the tank and the position of the sending unit is the reason we are seeing this gage response. As some of you have pointed out the tank may have lots of fuel volume up high and lesser volume lower down in the tank where the sender is located. That maybe why after a complete fill the gage reads full for so long, then as the fuel level drops the sensor placement causes it to respond to what appears to be a more rapid fuel level drop. System is not very linear due to tank geometry and sensor placement.
I'll run it a little longer to see how its responds before I panic. It apears the neddle came off the full peg slightly yesterday.

As for Ag fuel here is a link to a JD ULSD summary I thought was interesting,

Does John Deere allow the use of Ultra-Low-Sulfur diesel fuel? : Ultra-Low-Sulfur diesel fuel in John Deere Engines.

15ppm is coming to Ag in 2010, currently at 500ppm sulfur content

I use Stanadyne "Lubricity" and "Performance Formula" in my older 7.3L Ford Diesel.

nmu98 · May 22, 2009

I was at a 1/4 tank last night and while the tractor was warming up I started filling the fuel tank with a 5 gallon container. One of the ventless ones, slooooow....

I could visably see the fuel guage move as the fuel slowly went in. It took about 3.5 to 4 gallons to take the guage from 1/4 to full. I only added 6 gallons, and I could just start to see the fuel level in the tank. I know I could have added 2-3 more gallong, if not more....

So I would guess that you will burn off about 5-6 gallons of fuel before the guage moves. Once it moves, from full to empty is 5 gallons.

Thats how mine works....You experience might vary