DK40HST Won't Start.

[kco]

James, thanks for the clear trouble-shooting explanation. I have printed a copy and put it in my DK service manual for future reference(that I hopefully won't need!).

I am watching this thread because I was having intermittent start problems with my DK35SE HST. But I think I got lucky. I sprayed a bunch of contact cleaner in the key switch weeks ago and the problem has not reappeared.

Nick, good luck with your repairs. At least now that the problem is permanent it should be easier for the dealer to diagnose it.

 

[k0ua]

James, thanks for the clear trouble-shooting explanation. I have printed a copy and put it in my DK service manual for future reference(that I hopefully won't need!).

I am watching this thread because I was having intermittent start problems with my DK35SE HST. But I think I got lucky. I sprayed a bunch of contact cleaner in the key switch weeks ago and the problem has not reappeared.

Nick, good luck with your repairs. At least now that the problem is permanent it should be easier for the dealer to diagnose it.

Yes, as you know, the key switch has been a source of problems in these models, particularly when exposed to rain. I had a problem with mine and sprayed some fluid film in it about 2 years ago and have had no problem with it since.. Many have taken it apart and cleaned them up, and lubed them. But the simple spraying seems to have solved my problems with the key switch.

 

[ritcheyvs]

I am backing out of this discussion, in part because I don't have a real DK40SE schematic (been assuming similarity to EX,which could be wrong), in part because OP decided to take it to his dealer, and in part because there is little new diagnostic information (such as measurements proposed in http://www.tractorbynet.com/forums/kioti-owning-operating/325421-dk40hst-wont-start-7.html#post3986687)

But I will add that , even after swapping batteries, the measured battery voltage is WAY LOW. We don't know if this is with the engine running or stopped but it's low either way. I think the OP said his meter reads almost 15 v on his truck battery when the engine is running so the meter is probably OK. Also, I think he said the tractor battery functions OK in the truck (does the truck have glow plugs?). He never said if he charged or tested the battery like Erik suggested. At this point I suspect his alternator isn't functioning and/or his glow plugs don't shut off which discharges the battery. I suspect some element in the start logic (cruise unit maybe?) is voltage sensitive so it cuts out below some threshold voltage (10v?). When the battery was allowed to recover overnight the voltage climbed just above this threshold, at least until recently. But after the tractor is run, the battery voltage is low from starting and glow plug operation. But we don't know any of these things. If it were me, I'd start by verifying the alternator is working (13.5-15 v output when running). As Xfaxman points out, there is NOTHING normal about am 11.7 volt reading at the battery (not to mention 9.75).

For James, it always cranks and starts (so far) when he jumps it at the starter solenoid or the start relay connector, so the immediate problem seems to be the start logic but the root cause may be low battery voltage.

 

[Coyote machine]

Wow and Wow, is all I can say that this issue is still a mystery.:confused2::shocked:
Nick, I wouldn't feel bad that you don't currently possess the skills to fix this intermittent problem. It takes years sometimes and lots of specialized training and hands on experience for most trade technicians to be good at troubleshooting and fixing intermittent problems. James K0ua makes it seem easy; and you've been fortunate to have some of the best of the TBN board members on the case with your issue, but it persists and compounds the problem AND the solution since only you are there with the beast.
When all else fails sometimes having a fresh pair of eyes and hands, meters, etc. can make a difference.
What I know is you have done a good job of trying to get us the answers to the questions we have posed, but again having a dealer shop where the tech can use the right schematic for your specific electrical system and copious parts sitting on the shelf or some other tractor on the dealer's lot can make it easy, sometimes, definately not always, to make progress you just may not be able to achieve.
We will all be anxiously awaiting the final outcome of this electrical puzzle/nightmare because we all clamor for knowledge of solutions to problems such as your tractor, IMHO.

Personally I think it has to be taken back to square one and to use logic, proper troubleshooting methodology and known to be good diagnostic tools/meters to insure accurate reading through which an attack plan can be rendered, then approach the problem with a fresh mind until it's solved. Somewhere along the line we've missed some crucial detail that as yet alludes us, partly because of what's been mentioned about trying to troubleshoot a difficult problem from cyberspace. We really need an active video link between the collective brain power of team Kioti and your tractor, so we could be your eyes and ears on this. Maybe a live feed through your ISP? Until then, we're mostly out of other options.:confused3:

 

[k0ua]

Wow and Wow, is all I can say that this issue is still a mystery.:confused2::shocked:
Nick, I wouldn't feel bad that you don't currently possess the skills to fix this intermittent problem. It takes years sometimes and lots of specialized training and hands on experience for most trade technicians to be good at troubleshooting and fixing intermittent problems. James K0ua makes it seem easy; and you've been fortunate to have some of the best of the TBN board members on the case with your issue, but it persists and compounds the problem AND the solution since only you are there with the beast.
When all else fails sometimes having a fresh pair of eyes and hands, meters, etc. can make a difference.
What I know is you have done a good job of trying to get us the answers to the questions we have posed, but again having a dealer shop where the tech can use the right schematic for your specific electrical system and copious parts sitting on the shelf or some other tractor on the dealer's lot can make it easy, sometimes, definately not always, to make progress you just may not be able to achieve.
We will all be anxiously awaiting the final outcome of this electrical puzzle/nightmare because we all clamor for knowledge of solutions to problems such as your tractor, IMHO.

Personally I think it has to be taken back to square one and to use logic, proper troubleshooting methodology and known to be good diagnostic tools/meters to insure accurate reading through which an attack plan can be rendered, then approach the problem with a fresh mind until it's solved. Somewhere along the line we've missed some crucial detail that as yet alludes us, partly because of what's been mentioned about trying to troubleshoot a difficult problem from cyberspace. We really need an active video link between the collective brain power of team Kioti and your tractor, so we could be your eyes and ears on this. Maybe a live feed through your ISP? Until then, we're mostly out of other options.:confused3:

Agreed, we (as a collective group) have done about all we can do through this medium. As a group we have fixed many of these problems here, but some can be a tough nut to crack.

If I may delve off into telling "war stories" for just a moment, I signed on to a new job back when I was about 21 at a different Television repair shop. I was already experienced, but learning is an ongoing thing. Anyway, when given the tour of the new shop, the owner/chief tech. pointed to the "tough dog" set over in a corner which he and every other tech had taken a look at for several months. The owner of the set had become disgusted and bought a new TV and traded in this fairly new set to get rid of the problem. The problem was that this set did a vertical roll about once every 5 minutes. Vertical sync, was a bit unstable, but would lock in except it would roll about once every 5 minutes and was therefore pretty annoying.

I worked on the set off and on for about 2 months when I did not have anything else to do. I did a lot of waveform tracing with an oscilloscope in the vertical synchronization circuit. What I eventually found was a small disc ceramic capacitor that when I removed it and tested it on a curve tracer reacted more like a diode (a semiconductor device) than a capacitor.

It had a pronounced semiconductor "knee" which no capacitor should ever have. Somehow this had formed naturally inside the body of the capacitor. Anyway I replaced this component and the vertical sync was as tight as a tick, and it never rolled again.

I know this has nothing to do with your tractor, but I use it to illustrate that some problems can be "tough dogs" and are very difficult to find and repair. Sometimes a new set of eyes and hands, can find things that even generally better tech's may overlook.

 

[chuck172]

Boy I like how you think James.

 

[k0ua]

Boy I like how you think James.

Thank you.

 

[TJP89]

I have to agree that it's time for a dealer, I think you are still under warranty if it's only 2 yrs/100hrs. The only thing I can think is the low voltage on the battery (draw somewhere) keeps tripping the start logic in the cruise module, causing your problem. That tractor needs to be gone over with a fine tooth comb.

 

[k0ua]

I have to agree that it's time for a dealer, I think you are still under warranty if it's only 2 yrs/100hrs. The only thing I can think is the low voltage on the battery (draw somewhere) keeps tripping the start logic in the cruise module, causing your problem. That tractor needs to be gone over with a fine tooth comb.

I would love to have an hour with it. Not saying I could fix it, but It would do my heart good to try.

 

[TJP89]

I would love to have an hour with it. Not saying I could fix it, but It would do my heart good to try.

Same here, something about experiencing the issue in person.

 

[murphy1244]

I would love to have an hour with it. Not saying I could fix it, but It would do my heart good to try.

But hopefully not on your machine right?

 

[k0ua]

But hopefully not on your machine right?

No, I meant an hour with his machine with the problem.. Heck no I don't need trouble in mine!:shocked:

 

[murphy1244]

No, I meant an hour with his machine with the problem.. Heck no I don't need trouble in mine!:shocked:

I know what you meant, just funnin ya.

 

[Nick61]

I thank all of you for your input with my problem. One stroke of good news is that my dealer was bought out by another dealer on Jan, 1. This new dealer is only an hour away instead of the two and a half from the original dealer. They are waiting for me to bring it in. I am having a hard time because I am using the tractor almost every day and I don't want to be without it for who knows how long. Especially since this new dealer hasn't been a Kioti dealer until now. Do dealers give loaner tractors? I sure hope so. My wife wants a new one since this has been a off and on problem for almost the whole time I have owned it. Anyone interested can fly out to California and help with the problem. Our weather is great right now!

Nick

 

[kco]

As long as it is starting OK for now I would simply wait for a time when I would not be using it for several days. You could rig up a simple push button to start it in the meantime. It might be best to wait a bit anyway, so the new dealer has a chance to get up to speed with the tractors and has some inventory on site. Then you could schedule a time convenient for you both and when the dealer is sure he can devote time to it.

It must be frustrating to have had this problem from the start. But it is just difficult to trace and not a serious defect.

 

[TJP89]

...Anyone interested can fly out to California and help with the problem. Our weather is great right now!

Nick

Dang, I was just out in CA, around LA. The weather out there certainly beats the 20s with wind in MI.

 

[Nick61]

Hi all! I finally got around to take my DK40HSE in for the no crank over issue. I got a call yesterday from the dealer and they found the problem. It is a diode on the ignition side of the circuit. Makes sense why when the tractor was hot it wouldn't crank over and when it was cold it would start. They said they ordered one. Heck order me two, this has been a nightmare. I have 170 hours on the tractor. I bet 30 are in idle! I hope all that tried to help me on this gets to see the end result.

Thanks Again,
Nick

 

[Nick61]

bump it to the top.

 

[k0ua]

Glad you reported back Nick. I would guess either the diode in series with the start relay coil or the suppression diode in parallel with the start relay coil.

 

[kco]

Hi all! I finally got around to take my DK40HSE in for the no crank over issue. I got a call yesterday from the dealer and they found the problem. It is a diode on the ignition side of the circuit. Makes sense why when the tractor was hot it wouldn't crank over and when it was cold it would start. They said they ordered one. Heck order me two, this has been a nightmare. I have 170 hours on the tractor. I bet 30 are in idle! I hope all that tried to help me on this gets to see the end result.

Thanks Again,
Nick

Yes, thanks for letting us know Nick. I was going to answer your notification of the solution but wanted to study the circuit diagram to see if I could come up with an intelligent question. Of course, no such luck. Until now, when K0ua's comment gave a clue as to where to look. That got me to look up a "suppression diode" and the circuit diagram in K0ua's post #16 of this thread makes a bit more sense.

So, I have some questions. Which diode failed? Where is it located? Are both diodes internal to the start relay or are they separate components?

In looking at circuit diagrams, I notice the HST ROPS tractors have the series and parallel diodes whereas the Cab model just has the parallel diode. I wonder why that is so? No wonder I don't understand these diagrams!

Edit: One more question--does your comment about starting when cold mean the problem diode just failed when the temperature increased?