MX5000 completely dead...need help

[msinc]

Hello all, first post and I need some help figuring this thing out. Rather than post a long, drawn out story of what lead up to this tractor dying I will post the basics of what's going on first. I have found some other things that needed correcting, but I don't want to confuse anyone. Had it since new and never had any electrical problems before. I don't use this tractor every day, more like once or twice a week. In the last month or so it started stalling. Totally random and could happen anytime or run all day no problem. Sometimes it would just slow way down for a few seconds and rpm's would go right back up but sometimes it would cut off. Never, not once did it ever fail to immediately restart. The engine runs perfectly and the machine only has like 500 hours on it.
Because the tractor runs so good and would start so easy I really believe this is some simple stupid electrical problem and I looked at all the OPC safety switches. Seemed to all work fine and tested okay with a volt meter. Next day I went to use it and it would not crank. In fact, all that happened was the indicator lights in the dash would blink momentarily and go right out immediately.
The ignition switch just didn't feel right, it felt like it was full of gravel and not smooth so I replaced it with a new one. Now the dash lights no longer blink and the tractor does absolutely nothing. No sounds, no clicking, no lights no, nothing, with the exception of the key being moved that is it, zero. The battery is about 6 months old and measures 13.1 volts. I measure 13.1 volts at the ignition switch. What lies between the ignition switch and the starter solenoid that can cause this condition??? I bypassed the time delay relay for the OPC system when it was stalling and the tractor would start up and run, but still stall. I have again bypassed it but no change so I don't think that is the problem. No fuses are blow and the big 40 amp main is good.
Any help is greatly appreciated and thanks in advance for reading this.

 

[SidecarFlip]

Aftermarket switch or Kubota part?

 

[D2Cat]

Welcome to the forum. I'd start off with the simple stuff. Have the battery load tested. Voltage may be fine, but under a load...not so good. Make sure the battery cables are clean at the battery post clamps and no oxidation showing under the insulation there. At the opposite end of the ground cable, remove the bolt from the cable and clean the metal frame and the cable eye. Sound too simple, but make sure you have a good clean, tight connection at the starter.

When that is confirmed, I'd begin checking wires. Like you mentioned, it's probably something simple. Just need patience to find it.

 

[dvcochran]

I would work backwards from the source (battery). This is typical control troubleshooting when you don't have an idea where the problem may originate. The starting could be as easy as giving your battery posts and terminals a good cleaning. Check where the negative cable grounds to the frame and make sure it is clean. You can always try to jump straight from the battery to starter to see if the tractor turns over as a test.
It does sound to me like you have two different problems. Electrical problems are most often on or off, not always but most often. When you say the engine is stalling that sounds like a fuel related issue. I have learned this is quite common on Kubota's. I went through a similar issue with my M9 where it would run fine for a while then start stalling, then pick back up. After two attempts I found grass back in the fuel line where you could not see it going to the separator.
Assuming you find the starting/electrical problem and it is still stalling, save yourself some time and frustration and run new fuel line from the tank to separator, to filter, to lift pump, all the way to the injector pump. It is maybe a one hour job.

 

[msinc]

Aftermarket switch or Kubota part?

Yes sir, it is in fact a Kubota part and thank you for the reply.

 

[msinc]

Welcome to the forum. I'd start off with the simple stuff. Have the battery load tested. Voltage may be fine, but under a load...not so good. Make sure the battery cables are clean at the battery post clamps and no oxidation showing under the insulation there. At the opposite end of the ground cable, remove the bolt from the cable and clean the metal frame and the cable eye. Sound too simple, but make sure you have a good clean, tight connection at the starter.

When that is confirmed, I'd begin checking wires. Like you mentioned, it's probably something simple. Just need patience to find it.

I jump started another vehicle {don't have an actual load tester, but I'd say that will do it} and I verified ground connection with a VOM. I did in fact clean the ground connection too. I will begin with the wires in the am and post what I do or do not find. Thank you for the reply sir!!!

 

[msinc]

I would work backwards from the source (battery). This is typical control troubleshooting when you don't have an idea where the problem may originate. The starting could be as easy as giving your battery posts and terminals a good cleaning. Check where the negative cable grounds to the frame and make sure it is clean. You can always try to jump straight from the battery to starter to see if the tractor turns over as a test.
It does sound to me like you have two different problems. Electrical problems are most often on or off, not always but most often. When you say the engine is stalling that sounds like a fuel related issue. I have learned this is quite common on Kubota's. I went through a similar issue with my M9 where it would run fine for a while then start stalling, then pick back up. After two attempts I found grass back in the fuel line where you could not see it going to the separator.
Assuming you find the starting/electrical problem and it is still stalling, save yourself some time and frustration and run new fuel line from the tank to separator, to filter, to lift pump, all the way to the injector pump. It is maybe a one hour job.

I believe the electrical issue is more than just a bad of faulty connection, because there is no power to activate anything. If it was just a bad connection I would think the dash lights would light and/or the glow plug relay would at least click or the indicator light would glow or blink. Whatever it is is a wide open circuit...zero voltage change when the key is turned to any position. Thanks for the reply sir!!!!

 

[Adam G]

Ground circuits fail under load. They can test fine with a volt meter while not under load.
Wiggle the wires at your ignition switch while attempting to crank over engine. If the harness at the switch was all you touched when you replaced the switch, sounds like you might have a broken or bad connection at the switch.

 

[Mark_BX25D]

Ground circuits fail under load. They can test fine with a volt meter while not under load.

This.


This confuses a lot of people. You can measure plenty of joltage with a meter, but put a load on it and it goes away now.


That's why a test light is a good complement to a meter. A meter won't load a circuit, but a test light will. Sometimes not enough to show the problem, though. Depends on the circuit.

A poor connection, whether on the ground or the hot side, will show this behavior. This can be from a cracked or loose terminal or from corrosion.

 

[Russell King]

Research the safety switches and verify they are good/bypass/replace them after you get it cranking. One may be going bad and trying to shut the tractor down.

On the crank problem, did you try to jump power directly to the starter from the battery? Be safe since the engine should spin if it is working, doubt it could start but slightly possible.

 

[msinc]

Ground circuits fail under load. They can test fine with a volt meter while not under load.
Wiggle the wires at your ignition switch while attempting to crank over engine. If the harness at the switch was all you touched when you replaced the switch, sounds like you might have a broken or bad connection at the switch.

I understand the importance of a good ground. I also understand that a VOM can show continuity. but the device will still not work. It doesn't take much of a contact to show continuity and it does take a good contact to carry amps. This thing is completely dead, just as if the positive lead was disconnected from its terminal. I would think that if it had a poor connection somewhere the indicator lights in the dash would still light up or at least blink when the key was turned.
The new ignition switch comes with a new harness about 6 or 8 inches long with a quick disconnect "Molex" type connector. I did in fact double check that it was properly "connected".
As far as I can tell, from the ignition switch there is a relay called a "key stop" relay and also the time delay relay for the opc system. There is also a relay for the blinkers and flashers and one for the glow plugs. I have located and identified all but the key stop relay. It is my understanding that this one can cause the tractor not to start because when it fails the fuel shut off solenoid does not reset {seems like that would kill the battery if so}. I have never experienced this relay going bad and just don't know if it shuts down everything completely, like what's going on, or if the dash lights still come on and maybe on of the other relays might click too and nothing else happens or not.
Folks that have commented on the key stop going bad just say "the tractor stalls and/or wont start" but I have never heard any other details.
I haven't exactly been easy on this tractor and so in the morning I intend to get under it and check for some kind of possible damage to any wires. One reason I believe it's something stupid and simple is that two days before it died completely it ran the worst it ever did, literally stalling out every 5 seconds until I eventually limped it home. Then, as if by magic, it started up and ran perfect the entire next day. Then the blinking dash lights and now zero. Doesn't seem like a big wire broken or damaged would be able to get "better" for a day and then puke for the last time the next, but stranger things have happened, especially mechanical. Thanks again for the reply!!!!

 

[msinc]

Research the safety switches and verify they are good/bypass/replace them after you get it cranking. One may be going bad and trying to shut the tractor down.

On the crank problem, did you try to jump power directly to the starter from the battery? Be safe since the engine should spin if it is working, doubt it could start but slightly possible.

Yes sir, best I can tell there are four that I am aware of, the neutral start, the PTO, the seat and that time delay relay. All are capable of preventing the tractor from starting. All are bypassed at this time and it still is dead. Unless there is another one I am not aware of/didn't find.
Before any one goes off on 42 posts of safety, "my god you gotta hook them all back up right away before you kill yourself" lecture, rest assured I will connect them all when I figure this thing out. They are only bypassed temporarily for diagnostic purposes.
I have not tried to hot wire the start solenoid because I am pretty sure that system, by and of itself is working. I will give that a try in the am. Thanks for the reply, it is greatly appreciated!!!!

 

[nocash247]

I had a friend that had a similar problem. Almost exactly the same but he had lights, turn the key and absolutely nothing. After talking to a few people here landed in an ignition switch which it was not. He finally towed it to a dealer and they found a corroded battery cable, not connection the cable... Everything back to normal.
Next thought. Have you tested your new switch? I had an issue with my F150 the rear door showed open all the time, bad switch right 99% of the time? So I replaced it. Nope. Traced the harness and found an open. Fixed it and still the door showed open. Now I'm pissed off. Traced and tested from the control box back to the brand new switch to find out I had got a bad one right out of the box. Just because it's new doesn't mean it's good.

 

[msinc]

I had a friend that had a similar problem. Almost exactly the same but he had lights, turn the key and absolutely nothing. After talking to a few people here landed in an ignition switch which it was not. He finally towed it to a dealer and they found a corroded battery cable, not connection the cable... Everything back to normal.
Next thought. Have you tested your new switch? I had an issue with my F150 the rear door showed open all the time, bad switch right 99% of the time? So I replaced it. Nope. Traced the harness and found an open. Fixed it and still the door showed open. Now I'm pissed off. Traced and tested from the control box back to the brand new switch to find out I had got a bad one right out of the box. Just because it's new doesn't mean it's good.

I will carefully check both battery cables tomorrow. It has to be something stupid like that because this thing went from running perfect one day to cold stone dead over night. Strange that it has 13.1 volts at the ignition switch though. If I read from terminal to terminal I get 13.1v, same as at the switch. Seems like if it was a cable/connection that was bad enough to make the entire tractor dead I might show voltage, maybe even get a test light to glow dull, but I doubt I would have the full same voltage reading at the switch.
I will verify the new ignition switch too, yes, I have received parts that were bad right out of the box too. Thanks for the reply sir!!!!

 

[mattwithcats]

Locate the ground connections on the tractor.
Remove the wires, gently wire brush both the bolt, and the wires.
Reassemble...

Fighting a no reverse lights on my car, bad ground was the cause...

 

[BigG]

I had a GMC pickup that would start one day and not the next. It has completely dead. Cleaned the terminals and ground to no avail. Checked the battery it was old so I replaced it as it is my wife's truck and wanted no problems. That lasted about a week before it would not start. New alternator, no improvement. Finally replaced the ground wire and I have not had a problem since. I skinned the wire to find the inside full of corrosion. Looked good on the outside. The terminal end and the eyelet end were clean and good looking but the cable could not carry the load.

 

[dvcochran]

I believe the electrical issue is more than just a bad of faulty connection, because there is no power to activate anything. If it was just a bad connection I would think the dash lights would light and/or the glow plug relay would at least click or the indicator light would glow or blink. Whatever it is is a wide open circuit...zero voltage change when the key is turned to any position. Thanks for the reply sir!!!!

Voltage and current are bed partners for electricity to work. But just like many marriages they do not always get along. Voltage (apparent) can test fine with a meter and even light up a couple of low current lights. But when heavy demand like starting the engine is applied and the current cannot flow cannot flow due to a conductivity problem (bad connection) nothing will happen. Think of a pinched garden hose under pressure. The potential is there but it cannot go anywhere.
In some ways this is better than a partial connection when dealing with high currents like a starting system. A partial connection is when you see arcing and sparks flying everywhere which can really cause damage to physical components.

 

[dvcochran]

This.


This confuses a lot of people. You can measure plenty of joltage with a meter, but put a load on it and it goes away now.


That's why a test light is a good complement to a meter. A meter won't load a circuit, but a test light will. Sometimes not enough to show the problem, though. Depends on the circuit.

A poor connection, whether on the ground or the hot side, will show this behavior. This can be from a cracked or loose terminal or from corrosion.

Exactly right. This is why I still use an analog meter with an isolated DRO for very delicate measurements.

 

[Mark_BX25D]

Locate the ground connections on the tractor.
Remove the wires, gently wire brush

Gently, schmently!

Get rough with those cables and connections! That's how you find the marginal stuff!

If it's nearly broken, break it so you know it's broken! Then you can fix it and know it's fixed.

 

[Pau7220]

Gently, schmently!

Get rough with those cables and connections! That's how you find the marginal stuff!

If it's nearly broken, break it so you know it's broken! Then you can fix it and know it's fixed.

I was thinking the exact same thing! Don't forget the fusible link or slow blow fuse also... mine rotted internally from water intrusion.