MX5000D safety circuit problem

[cabbott]

I have a MX5000D that has electrical problem with safety circuits. When I move the shift selector from neutral to forward or reverse the engine shuts off. Also the same with PTO selector is moved to engage. I currently have both safety circuits bypassed so I can utilize the tractor. My question is does anyone on this forum know were you can get a complete electrical schematic that covers all the safety component's? I have the WORKSHOP MANUAL for the MX5000 but the electrical schematic is incomplete for the safety circuits. Any help appreciated.

 

[North Idaho Wolfman]

I'll look at my copy of the WSM later today when I get home and see if I can help you with it.

 

[scdeerslayer]

Sounds like an issue with the seat switch.

 

[cabbott]

All micro switches for safety circuits have been checked and they are OK. I have bypassed/jumper out the shift selector and PTO circuits and tractor will run as normal. I think there is a timed relay in this circuit that is bad. I do not know were the relays are located or how the wiring is run to it. Any help on a electrical schematic that shows the complete safety circuits would help.
Thanks for Your reply.

 

[100 td]

In a standard kubota scenario, PTO and Shift/Neutral switch are paralleled with the seat switch or OPC relay (operator presence control), have you bypassed the seat switch? With the seat switch/OPC relay, the circuit logic is detecting that you have either the PTO engaged, or the transmission in gear, and no one is sitting on the seat at the same time, so it shuts down the engine.

 

[North Idaho Wolfman]

The MX5000 does not have a OPC or a seat switch controlling it, it only has the 2 safety switches for starting.
Have you checked the starter relay under the dash?

 

[100 td]

When I move the shift selector from neutral to forward or reverse the engine shuts off. Also the same with PTO selector is moved to engage.

He's saying the engine shuts down when selecting gear or PTO, he hasn't said it won't start, hence the notes about seat/OPC control of the stop solenoid.
If there is no electric stop solenoid on this tractor, and it's a stop pull rod he must have other hydraulic/mechanical problems stalling out his engine.

 

[North Idaho Wolfman]

Yes I messed up and my starter relay was off, I must have been reading something on another post.

Ok now you ready to scratch your head...
How can a diesel that does not have a stop solenoid, shut off moving anything besides the stop cable or lever?

It doesn't have a stop solenoid so the engine is 100% mechanically stopped.
It doesn't have a seat switch.
It doesn't have an OPC computer.

Aside from starting it, that tractor doesn't even care if it has a electrical system at all, it doesn't need it to run.

If the tractor is truly a MX5000DT and someone hasn't randomly added a stop solenoid, the only issue that makes any since would be;
#1 Something is moving engaging the stop lever or cable.
#2 Something is causing the fuel line to be pinched shut.
#3 The brakes are set and you're actually stalling the tractor
#4 The transmission or rear end has an issue and is stalling the engine.

Wiring diagram:

 

[100 td]

NIW, now you're on the same wavelength!
It certainly sounds strange that shift or PTO kills it, "unless" he actually means it won't start, but he seems fairly clear that it shuts down.
And of course your thought about an added shutdown solenoid is not out of the question.
And I'll have to toss you for one of the other four!
One other, is it possible that it's just getting enough fuel to start, but as soon as any load is added the fuel pump is not opening at all?

 

[North Idaho Wolfman]

NIW, now you're on the same wavelength!
It certainly sounds strange that shift or PTO kills it, "unless" he actually means it won't start, but he seems fairly clear that it shuts down.
And of course your thought about an added shutdown solenoid is not out of the question.
And I'll have to toss you for one of the other four!
One other, is it possible that it's just getting enough fuel to start, but as soon as any load is added the fuel pump is not opening at all?

Yep a air locked system could cause issues.

This is the part that has me baffled
" I currently have both safety circuits bypassed so I can utilize the tractor."

how does bypassing the 2 safety switches effect it's running????

 

[100 td]

This is the part that has me baffled
" I currently have both safety circuits bypassed so I can utilize the tractor."
how does bypassing the 2 safety switches effect it's running????

Well it's always possible that you hit the nail on the head earlier!

........and someone hasn't randomly added a stop solenoid

We'll have to wait and see if there is a better or different explanation coming from him.

 

[100 td]

So the PTO is activated by the clutch, and the forwards or reverse is activated by the clutch, so commonality mechanically to some extent, is it just starving under load or something else?

 

[cabbott]

Thanks for all comments. I will try and clarify all the above comments. The tractor runs fine with the PTO and F/R shift selector safety micro switches bypass, ie. shorted out. I disconnected the cables to micro switches and put jumpers in the connectors. This model tractor MX 5000D does have a OPC/Timer relay associated safety circuits. I just cannot find a electrical schematic that clearly identifies how the overall safety circuits are wired. I just wanted to find a schematic so I could trouble shoot the entire circuit before paying $80.00 for the OPC relay.

 

[North Idaho Wolfman]

cabbott,
Sorry for the confusion, It looks like there is probably a break in the serial #'s and there is a difference in newer and older units.

Older units were all mechanical shut off, did not have a stop solenoid, and did not have an OPC or a seat switch.
Newer units have both mechanical and electrical shut off, they do have a 5 Safety switches, 2 for PTO, 2 For gear, 1 for the seat.
Looks like WSM is 97897-12920

Now back to the problem, If shorting out the switches allows it to work then you should have a bad switch and not a bad OPC.
To confirm this use an ohm meter and with the switch not pressed check ohms (should be infinite), then with the switch pressed it should be 0, if any switch does not do that then you have a bad switch.
Go through one switch at a time and eliminate the bad switch.
My bet would be as 100 td said, it's got a bad seat switch.

 

[100 td]

...It looks like there is probably a break in the serial #'s and there is a difference in newer and older units.
Newer units have both mechanical and electrical shut off, they do have a 5 Safety switches, 2 for PTO, 2 For gear, 1 for the seat.

The Wolfman saves the day again. Yay!

 

[cabbott]

Thanks for the reply. Still looking for a complete wiring diagram of safety circuit. All micro switches in safety circuit or good when checked with ohm meter. The OPC relay has a timer associated with it and I would like to know just how it is wired so I can trouble shoot it.
Thanks Cabbott

 

[North Idaho Wolfman]

What WSM do you have?

 

[100 td]

Looks like WSM is 97897-12920

What WSM do you have?

Hey NIW,
Your listed WSM above is floating around the net and doesn't list/show all the safety's you have previously noted. I expect he has that one. Using your divine powers, perhaps there is another manual, or possibly a supplement for this model tractor with more features? Or maybe the one posted online has a section or sheet missing from it?

From tractordata - The Kubota MX5000 was marketed as an intermediate model between the L and M series line. (Perhaps because of this there is a gap in the manuals somewhere?)

 

[North Idaho Wolfman]

Ya know I never bothered to look at the P/N of my manual, I assumed it was a different manual than the one I listed, and the one I have is wrong.
The only thing I can think of is to get a MX5100 manual, which I don't have and see if that matches the his tractors setup.

Anyone have a MX5100 manual that they would be willing to scan the wiring diagram and send it to me?

 

[100 td]

All micro switches in safety circuit or good when checked with ohm meter.

Hi cabbott,
Do you currently have the seat switch bypassed? Is it a 2 wire or 4 wire seat switch?