2010 DK40 SE Won't Start

[ritcheyvs]

I doubt the diode is the problem. If the diode was open-circuit it would just allow sparking at the relay contacts when they open. If it was shorted it would be hard to get the 10 volts you observed.

Question: did you measure that 10v one-second pulse with the stop solenoid (SS) connected or was that an open-circuit measurement at the disconnected connector?

If this was measured with the SS connected, I think that 10 volts at the pull coil should be sufficiency to energize the SS. So in that case, I suspect you have a bad stop solenoid. You can test this by applying 12v direct from the battery to the pull contact (for one second) to see if that energizes the SS.

If this 10v was measured with the connector disconnected (no load) it doesn't tell us much except the relay is getting the pulse from the display unit.

 

[k0ua]

I doubt the diode is the problem. If the diode was open-circuit it would just allow sparking at the relay contacts when they open. If it was shorted it would be hard to get the 10 volts you observed.

Question: did you measure that 10v one-second pulse with the stop solenoid (SS) connected or was that an open-circuit measurement at the disconnected connector?

If this was measured with the SS connected, I think that 10 volts at the pull coil should be sufficiency to energize the SS. So in that case, I suspect you have a bad stop solenoid. You can test this by applying 12v direct from the battery to the pull contact (for one second) to see if that energizes the SS.

If this 10v was measured with the connector disconnected (no load) it doesn't tell us much except the relay is getting the pulse from the display unit.

If the 10 volts was measured on the solenoids pull connection with the solenoid connected I suppose it would be possible that the pull coil relays contacts are burned and therefor high resistance and causing the voltage drop. You should be able to find the diode in the harness and pull it out of its connectors but like Scott said , diodes usually fail shorted or open. neither would really account for the 10 volts. If it was shorted it would blow that 25 amp fuse, if open you would not know it. As Scott said you should be able to jumper 12 volts from the battery for 1 second and see if the solenoid pull coil is working correctly. This would bypass the function of the relay that normally provides the voltage thru its contacts for this purpose. Of course you could go get another relay too and replace it.

 

[TimbourLarry]

With your collective assistance I believe the mystery is solved!. Yesterday, I unplugged the starter relay terminal and plugged it into the engine stop relay, turned the key on and the solenoid pulled back immediately and held. I have ordered a replacement and hopefully, will have no further problems with this issue as long as it was just a faulty relay and not due to another electrical problem. thanks again for all the expert advice, diagrams etc. TimbourLarry

 

[TimbourLarry]

Help!! I got the new relay, plugged in the terminal, turned on the key to may sure the solenoid pulled back which it did, installed the solenoid and the tractor again would not start! I removed the solenoid to check and it will no longer pull back-back to same old problem. Is something frying the relay? This is almost laughable as I bought the Kioti, so I could have a dependable tractor. My 3510 Mahindra doesn't like to start in cold weather. Any help will be appreciated.

 

[Coyote machine]

Are you saying you energized the solenoid before it was attached to the starter? You bought a new relay, just to clarify, which one?
So when you removed the solenoid, after having attached it to the starter it now won't energize, similar to before when you swapped out the original relays from your firewall?

 

[TimbourLarry]

Are you saying you energized the solenoid before it was attached to the starter? You bought a new relay, just to clarify, which one?
So when you removed the solenoid, after having attached it to the starter it now won't energize, similar to before when you swapped out the original relays from your firewall?

I bought a new starter relay plugged it up and then turned the key on to energize and test the sol if which pulled perfectly. I then mounted the stop solenoid on engine and then attempted to start the engine with no success. I the removed the solenoid and energized it again and this time it did not pull...back to the same old problem. I could be wrong but thought I heard a sizzle sound when I turned the key on after installing the solenoid. Thanks

 

[murphy1244]

Check those ground cables

 

[k0ua]

I bought a new starter relay plugged it up and then turned the key on to energize and test the sol if which pulled perfectly. I then mounted the stop solenoid on engine and then attempted to start the engine with no success. I the removed the solenoid and energized it again and this time it did not pull...back to the same old problem. I could be wrong but thought I heard a sizzle sound when I turned the key on after installing the solenoid. Thanks

I am wondering if it is possible that the pull coil of the solenoid might be shorted to the chassis of the solenoid. When you tested the solenoid did you have it just hanging out in the open air? and not touching the engine block? It the case of the solenoid is shorted to the pull coil, it would not have mattered if it was not touching the engine block. As there are 3 wires going to the stop solenoid in its connector, you have the pull wire, ground, and the hold wire. But lets hypothesize for a minute that the case of the solenoid IS shorted to the pull coil. it would then draw excessive current thru the stop relay's contacts when you then bolt the case of the solenoid back to the engine ground. possibly burning up the contacts. This is grasping at straws here, trying to fit a hypothesis into your description to what happened, and why the stop relay keeps failing. It would be easy enough to test, just take a voltmeter and measure between the case of the solenoid and engine ground when the 1 second pull voltage is energized. This seems very unlikely to me, but it is all I can think of at the moment. In any case you would seem to need another stop relay before you can move forward.

James K0UA

 

[ritcheyvs]

What James said. Get out the voltmeter again and test voltages at the SS terminals. You can also use the ohms scale to check for a short between the SS case and all three terminals (should read near infinite ohms) with the connector removed. Finally, there may be a problem with the diode failing to suppress arcing in the relay but I think it's very unlikely that one cycle of the relay would completely fry the points. There could also be an internal short between windings of the "pull" coil; this would cause the coil to draw higher current while reducing its ability to "pull" the solenoid.

On my (older) DK, there is a VERY distinct click when I turn the key to the "on" position and the stop solenoid operates; this may provide an audio clue if the SS is working or not.

When you swapped the starter relay to the SS relay connector, did that damage the start relay? If you stick the now failed (maybe) SS relay in the start relay connector does the starter still crank? Have you rechecked the fuses since this most recent failure; if you truly have a shorted SS it's likely you blew a fuse. Have you considered running +12v direct from the battery to the "pull" terminal (for one second) to see if that operates the "pull" coil? I generally recommend diagnosis over parts swapping but if you want to swap a pert, the SS is the next likely candidate.

 

[Coyote machine]

You guys got to this before I could reply to the answer to my inquires; oh well :confused3:
I agree, since the SS was energized before attaching it to the pump, and it worked, and then he attached it to the pump and when turning the key heard the sizzle my relay sound and NO action by the SS, there has to be a short which is causing the relay(s) to 'let out the smoke'.
If it were me, I'd replace the SS, and the relay at one time, because if he just replaces the relay and the SS is intermittent or internally shorted he's going to keep replacing relays until there are no more.
Agreed, this is not to suggest parts swapping for proper diagnostics, however, he can make a diagnosis of the SS before replacing it, to be sure it is the culprit. And check grounds and fuses too to make sure nothing has been missed prior to buying any further parts.

Report back your findings on the SS being shorted, please.

 

[TimbourLarry]

Thanks for all your responses and I'll try to answer the outstanding questions. Just to be sure that we are all on the same page the relay I replaced is the starter relay 30. in the picture James sent on page 4 which is on the far left or the 3rd relay to the left of the display unit. The stop relay in the picture is next to the display unit. I also have 2 stop solenoids (SS) as I got a new one when I incorrectly diagnosed the problem as the SS when the tractor would not start and I've tested both and neither work now but I haven't yet plugged the starter relay wires into the stop relay to see if that still works, but the engine cranks fine just not start. since I know longer have a Kioti dealer in the area I ordered the relay over the internet and I'm wondering if you guys know if a Mahindra, Kubota, JD would have a similar 5 prong relay that would work. I hope I've answered your questions and thanks again.

 

[k0ua]

Thanks for all your responses and I'll try to answer the outstanding questions. Just to be sure that we are all on the same page the relay I replaced is the starter relay 30. in the picture James sent on page 4 which is on the far left or the 3rd relay to the left of the display unit. The stop relay in the picture is next to the display unit. I also have 2 stop solenoids (SS) as I got a new one when I incorrectly diagnosed the problem as the SS when the tractor would not start and I've tested both and neither work now but I haven't yet plugged the starter relay wires into the stop relay to see if that still works, but the engine cranks fine just not start. since I know longer have a Kioti dealer in the area I ordered the relay over the internet and I'm wondering if you guys know if a Mahindra, Kubota, JD would have a similar 5 prong relay that would work. I hope I've answered your questions and thanks again.

I am confused by your reply here. Why are you replacing the start relay (30 in the photo) when you know the engine will crank? That relay must be functioning or the engine will not crank. But since it does crank, it is good!. You need to try replacing the stop solenoid pull coil relay, or test it by substituting the start relay wiring onto that relay to see if the engine will crank. This would test the functionality of that relay. If it is good we need to look elsewhere for our problem.. lets go over again how the stop solenoid and the relay that drives it works. The chain of events begin with the 1 second Ground pulse that comes out of the Display unit on connection point 33. This is connected to the low side of the stop relays coil.. again the connection point is labeled 33 on the schematic. The high side of the coil is on the positive ignition key connection. So the coil energizes, the contacts pull up for the one second (thru the 25 amp fuse)and this energizes the big high current of the pull coil inside the actual stop solenoid on the front of the injection pump. Now that the pull coil is pulled back for that one second, the hold coil that is energized by the ignition key will take over keeping the stop solenoid pulled back thru its low current "hold" coil.. This is fed thru the 10 amp fuse labeled "alternator/engine stop". There is also a diode shown near the stop solenoid on the schematic, its purpose is to suppress the "back EMF" that is generated when the coil de-energizes. If that diode was shorted It should blow that 25 amp fuse, or at least burn up the contacts of the stop relay and still blow the fuse.
So your mission is to determine does the 1 second ground pulse come out of the display unit? and pull the coil of the stop relay( third one from the left) Does it contacts pull up and supply the 1 second of high current thru the 25 amp fuse to the pull coil of the stop solenoid?, and is the hold coil energized from the ignition switch?. Lets go over what you said you know for facts: You state the engine will crank, there the start relay and all related circuitry is good. You state the engine will start and run if the stop solenoid is pulled back, but obviously the stop solenoid is not being pulled back for some reason. We need to find that reason.

James K0UA

 

[Coyote machine]

Don't confuse your issues further by swapping parts to the Kioti from another tractor. Follow what James outlined above, and let's get you rolling.:thumbsup:

 

[TimbourLarry]

James, eureka that was it!! I had mistakenly read a post about the 3rd relay from the right side and replaced the starter relay which was ok instead of the stop relay which turned out to be defective-rookie mistake. At any rate I changed the stop relay mounted the SS turned the key and heard the SS click and then the beautiful purr of the engine ...finally. Thanks for your patience and if I could I would send everyone an apple pie. Many thanks again!!

 

[k0ua]

James, eureka that was it!! I had mistakenly read a post about the 3rd relay from the right side and replaced the starter relay which was ok instead of the stop relay which turned out to be defective-rookie mistake. At any rate I changed the stop relay mounted the SS turned the key and heard the SS click and then the beautiful purr of the engine ...finally. Thanks for your patience and if I could I would send everyone an apple pie. Many thanks again!!

Hey we got ya fixed! Good deal!

 

[Coyote machine]

James, eureka that was it!! I had mistakenly read a post about the 3rd relay from the right side and replaced the starter relay which was ok instead of the stop relay which turned out to be defective-rookie mistake. At any rate I changed the stop relay mounted the SS turned the key and heard the SS click and then the beautiful purr of the engine ...finally. Thanks for your patience and if I could I would send everyone an apple pie. Many thanks again!!

Oh boy, an apple pie! Careful what you wish for. What's your address, I'll send you the pie mailing list!:licking:

Glad you got it fixed. Nice job James. Way to stay focused on the tractor at hand and the specifics of the issue.

 

[TimbourLarry]

You guys are great!

 

[seacap04]

Yeah, they are. We all learn a lot by reading the posts.