L4240 HST Stalling

[Dan Andrews]

L4240 HST kubota tractor stalling

 

[North Idaho Wolfman]

You're going to have to give more details!
Like when and how does it stall?
Does it die quick or does it bog down?
Does it stall when you hit the HST pedal?

 

[Dan Andrews]

You're going to have to give more details!
Like when and how does it stall?
Does it die quick or does it bog down?
Does it stall when you hit the HST pedal?

More information,
With or without any attachments on the tractor sometimes when I try to move either forward or reverse as I try to depress the HST peddle I can hear a click and the engine wants to stall, but if I quickly let up on the pedal the engine instantly recovers.

I have completely removed the seat switch and that didn't solve the problem.

I can accelerate the engine with the hand throttle without any problems, but as soon as I depress the pedal it wants to stall.

The tractor is a 2007 Grand L4240 cab, Hst and we only have 700 hours on it, also it is serviced regularly.

I have ruled out the fuel system, and seat switch, so believe it is something to do with the HST and electrics, but beyond that?

 

[D2Cat]

Sounds like your Auto Throttle Advance or the Stall Guard features not working correctly. Can't give any advise on checking it though.

 

[Russell King]

When you removed the seat switch, what did you do with the wiring?

I believe the tractor needs to “know” someone is sitting on the seat before it will allow the tractor to move. The seat switch indicates that to the tractor somehow on some tractors.

 

[North Idaho Wolfman]

Its sounding like you have a bad HST pedal sensor.
I need your Serial Number in order to figure out what generation of tractor yours is, as there was three generation of that model.
I can also help with the WSM (aka service manual) when I know which generation you have.

 

[Dan Andrews]

Thanks for all your replys,

Ok, some more info.
I have tryed disengageing the auto throttle, and stall Guard, that didn't make any difference.

I have found that the seat switch is a normally closes type, and when you sit on the seat it creates an open circuit, so by my removing it all together everything works even the PTO. But still the engine wants to stall when I depress the HST pedal.

Our Tractor is a 2007 Grand L4240 Cab, with HST transmission, the serial number is 32037
I am not sure what generation it is, but I know that after we bought our tractor they came out with an improved pedal, that gave it a bit lighter feel, so making it less fatiguing to operate, I did ask if our tractor could be upgraded to that pedal, and was told that it wasn't possible.

I appreciate all the help given.

Dan Andrews

 

[number two]

OPC(Operator Presence Control)?
The awesome Wolfman will know!
Good Luck!

 

[Dan Andrews]

OPC(Operator Presence Control)?
The awesome Wolfman will know!
Good Luck!

Thanks for that, I hope that he can figure it out.

Dan

 

[North Idaho Wolfman]

The L4240's in OZ have different serial numbers than in the US.
Your L4240 does not have a OPC (operator presence control) it had a ECU which does the job.
Your issue is most likely that the pedal control sensor is bad.
You'll need to talk with a local dealer to get the right part number.

 

[Dan Andrews]

The L4240's in OZ have different serial numbers than in the US.
Your L4240 does not have a OPC (operator presence control) it had a ECU which does the job.
Your issue is most likely that the pedal control sensor is bad.
You'll need to talk with a local dealer to get the right part number.

View attachment 118886

Thanks Wolfman,

Since the problem doesn't happen all the time, is there a way to test the pedal sensor?

Also I thought that I had eliminated the seat switch from the system, but have come to realise that, that was the seat tilt switch, and that there is also a seat switch as well.

I have unplugged both and will try and run the tractor later today to see if that changes anything.

I do appreciate all of your help, thanks.
Dan