MX5800 dies when rocking pedal forward or reverse (SOLVED)

[Cycledude]

I don’t own a Kubota tractor but on my LS if your not sitting in the seat the transmission needs to be in neutral and parking brake applied in order to start the engine. Also if your not sitting on the seat the PTO won’t turn on unless transmission is In neutral and parking brake is applied. Maybe it works different on Kubota.

 

[Chewwy]

MX5800 starts fine. Can be standing next to it or sitting on seat to start it. As soon as you rock the pedal to go forward or reverse, the engine cuts out. It will also quit when you turn on the PTO. Always restarts just fine. We've thrown a seat sensor at it and the pedal sensor found up under the dash. Neither part solved problem.

What part should we throw at it next? Trying to avoid loading on trailer and having it sit at the dealer for a month.

Thanks much

Could be a fuel flow issue. Check the fuel filter. Had similar issue with my L3240, didn’t stall but was greatly under powered when trying to increase speed or climb a hill. Fuel filter had a waxy substance in it. Replaced fuel filter, problem solved

 

[JWR]

Could be a fuel flow issue. Check the fuel filter. Had similar issue with my L3240, didn’t stall but was greatly under powered when trying to increase speed or climb a hill. Fuel filter had a waxy substance in it. Replaced fuel filter, problem solved

No. There is no fuel related issue that would allow starting and running the engine and then it be forced to shut down when you attempt tractor motion or to run the PTO. Chewwy you had a very different problem.

 

[rScotty]

Thanks for the PTO sequence diagram. The thing is with this tractor we've always been able to simply start the tractor and then the PTO standing next to it. No parking brake needed. No flipping the seat forward. We run both a feed grinder and a hay bale elevator from the PTO. The tractor was purchased used and there is no sign anyone bypassed any safety features.

I hope it isn't the ECU because it ain't cheap. That's for sure.

I'm betting it is one of the switch adjustments. On our Kubota M59, there are times when I can start the engine with the seat reversed and the hand brake off....and times when it wont crank unless the hand brake is on and the seat "reset" as well.

It doesn't make sense to me....but somehow the way that the ECU views the switch positions seems to have changed over the years, and I'm not sure why.

Last time it happened - last summer - I went through all the safety switches and carefully set their free play and engagement clearance, then pulled all the fuses and cleaned their contacts.
That seems to have worked. Now it works the same as it did when new.
But I'll admit that I have no idea why.....

 

[Kubota Red]

Seat switch (and it's circuit) is the only one that will kill the tractor when the pedal is pressed or the pto is turned on. Try starting it, tilting the seat forward and engaging the pto (the switch is designed to allow the pto to run if the seat is tilted forward). I have never heard of an issue like you described being an ecu problem. Most likely the switch (bad, damaged, misadjusted, etc.) and second would be the wiring harness.

 

[Worksmart]

Seat switch (and it's circuit) is the only one that will kill the tractor when the pedal is pressed or the pto is turned on. Try starting it, tilting the seat forward and engaging the pto (the switch is designed to allow the pto to run if the seat is tilted forward). I have never heard of an issue like you described being an ecu problem. Most likely the switch (bad, damaged, misadjusted, etc.) and second would be the wiring harness.

Thanks for this. I did exactly as you suggested and tipped the seat forward and got the PTO to work without killing the engine.

After that I really started looking hard at the seat switch and wiring. Lo and behold I found the broken(orange) wire. It was very hard to find as it was tight up against the connector on the end of the wiring harness. Hidden just inside the ribbed loom protector and some tape. Surprised we didn't catch it when we changed the seat switch a few days ago.

Thanks to all who chimed in!!

 

[thclimer]

Glad to hear you found the issue, thanks for letting us know.

 

[Bansil]

Thank you for follow-up