DK45S - Stop Solenoid Pull Not Working

[billboe]

So, my DK45S won't start (cranks but no combustion). At 1st it was intermittent but now nothing. I believe I traced it to the stop solenoid pull not getting enough voltage. FYI, this tractor has a 2 pin fuel stop solenoid (1 pin is pull and 1 pin is hold; ground comes from the engine).

Here are my troubleshooting steps:

• starts right up if i remove the fuel stop solenoid
• if i put 12v on the pull pin it cycles rapidly in and out (not sure if this is normal or not, but i assume it is)
• if i put 12v on the hold (and manually push in the plunger) it holds nicely
• the stop solenoid connector shows 12v on the hold pin
• the stop solenoid connector shows only 1v or 2v on the pull for a short period (my understanding is that it should show 12v for 1 second; it could be my cheap multi-meter isn't able to measure the 12v for a short period, but, since my test showed the solenoid pull works with 12v, i don't think this is the case)

So, my question is what component supplies the 12v to the pull pin for 1 second?

I've tried replacing the 3 relays on the firewall, but, saw no change. In fact, I removed each one in turn and I could still measure the 1v on the pull pin of the solenoid, so, I don't believe they are involved.

I check all the fuses and all are good. It is interesting that the fuse legend shows fuses for an "Engine Stop Timer" and "Engine Stop Relay" but I have no idea where those components are located!?!? None of the relays in the fuse box appear to be related (see above fuse picture link).

I'm not sure what the FFT Controller (under the dash) does and I'm not sure how to test it.

There is one other relay or ??? on the lower part of the firewall near the fuel filter, but, I don't know what that one does either (and I believe I did the unplug test and I still saw the 1v on the pull pin, but, now my memory is failing!)...

Anyway, ANY help would be MOST welcome!!! Thanks!!!

 

[billboe]

BTW, I brought the stop solenoid into the local Kioti dealer. They thought one of the pins was ground (instead of 1 pull & 1 hold). They "tested" it and determined it was bad because the hold pin appeared to do nothing. Then the parts guys could only find a 3 pin solenoid...

I then called Michigan Iron and Equipment, Kioti Tractors, Kioti Implements, Kodiak Attachments, Befco, Hound Dog Attachments, Dk Series Tractors, Central Michigan and talked to Bob... He knew immediately about the 2 pin solenoid and helped me further in my diagnosis of not enough voltage coming to pull pin.

Anyway... Just thought I'd add that...

 

[ritcheyvs]

I agree with all your conclusions except: if removing the stop solenoid relay did not prevent the 1 volt pulse you observed, it wasn't really the stop solenoid relay. I think the most likely cause is a bad stop solenoid relay. But there is another possibility. There is a diode in the wiring harness to suppress the big spark that would occur when power is suddenly removed from the "pull" coil. If that diode has failed, it could create short that would steal the current from the SS and pull the voltage down from 12 to 1 volt. I can't tell you exactly where that diode is except it is in the wiring harness between the SS relay and the stop solenoid.

Supplemental: If you measured that 1-2 volt pulse at the SS connector with it disconnected from the SS (open circuit), it is very likely a shorted diode is the problem. To answer your specific question, a box called the Display Unit provides a ground (for 1 sec) to the coil of the stop solenoid pull relay when you turn the key switch on. The other side of that relay coil is powered by the Display Unit fuse. The power for the pull coil comes from the Engine Stop Solenoid fuse via the relay. Power for the hold coil comes directly from the key switch as long as the key is on (not off or accessory).

By the way, the only available DK45s/451 service manuals only cover the old (pre front-of-engine stop solenoid) version of the engine. You need to look at an EX manual for correct information on the newer engine (and stop solenoid arrangement). I suspect the fuse labels are confusing because they did not update the decal for the new engine. The FFT controller generates the tachometer signal from a pickup sensor on the engine.

 

[billboe]

Thanks VERY much for your reply!

I agree with all your conclusions except: if removing the stop solenoid relay did not prevent the 1 volt pulse you observed, it wasn't really the stop solenoid relay. I think the most likely cause is a bad stop solenoid relay. But there is another possibility. There is a diode in the wiring harness to suppress the big spark that would occur when power is suddenly removed from the "pull" coil. If that diode has failed, it could create short that would steal the current from the SS and pull the voltage down from 12 to 1 volt. I can't tell you exactly where that diode is except it is in the wiring harness between the SS relay and the stop solenoid.

Do you know which relay is the SS relay? And I guess I don't understand how any current would flow to the SS if I had unplugged the correct relay. Doesn't the current flow thru the SS relay?

Supplemental: If you measured that 1-2 volt pulse at the SS connector with it disconnected from the SS (open circuit), it is very likely a shorted diode is the problem. To answer your specific question, a box called the Display Unit provides a ground (for 1 sec) to the coil of the stop solenoid pull relay when you turn the key switch on. The other side of that relay coil is powered by the Display Unit fuse. The power for the pull coil comes from the Engine Stop Solenoid fuse via the relay. Power for the hold coil comes directly from the key switch as long as the key is on (not off or accessory).

Thanks for this even if my eyes are turning a bit glassy...

By the way, the only available DK45s/451 service manuals only cover the old (pre front-of-engine stop solenoid) version of the engine. You need to look at an EX manual for correct information on the newer engine (and stop solenoid arrangement). I suspect the fuse labels are confusing because they did not update the decal for the new engine. The FFT controller generates the tachometer signal from a pickup sensor on the engine.

Wow! I found an EX manual (free online if anyone is interested; as well as CK, DK, & LX) and it is MUCH better than the DK45S service manual that I have! According to this manual, the stop solenoid relay is the right most relay on the firewall (as you face the firewall). Do you think this is correct for the DK45S?


Thanks again for your detailed message!!!



p.s. i never received an email when you replied to the thread even tho i was "subscribed" with email notification. i just removed my subscription and re-subscribed to see if that helps...

 

[chuck172]

How bout the link for the DK service manual billboe.

 

[billboe]

hey chuck... i just PMed you...

 

[ritcheyvs]

Do you know which relay is the SS relay?

Relay ID can be confusing. Usually, there are three relays on the "firewall" for the starter solenoid, the glow plugs, and the stop solenoid. The glow relay should have a higher current rating for the contacts (like 60 amp). The start and stop relays are usually identical and you can't be sure which is which by their location because it's easy to swap connectors, which would reverse which relay does what. To sort them out, you can "feel" which relay clicks on (and then off) when the key is first turned or use a voltmeter on the connector. With the key ON, both coil pins on the start relay should read zero. On the stop relay, one coil pin should always read 12v with the key on (the display unit supplies a ground to the other coil pin for one sec).

And I guess I don't understand how any current would flow to the SS if I had unplugged the correct relay. Doesn't the current flow thru the SS relay?

That was my point. If you pulled the connector from the true SS relay there should be zero volts at the pull pin of the SS connector. So if you still see that 1-2 volt (1 sec) pulse the SS relay must still be connected

Thanks for this even if my eyes are turning a bit glassy...

When current flows through a coil, there will be a spark if that current is suddenly interrupted as the energy (which is stored in the magnetic field) has to dissipate somehow. That's basically how the old breaker-and-coil ignition systems worked. This sudden discharge is a bad thing that can burn the relay points and do other damage. To prevent this, a back-biased diode is connected across the coil. That diode will not conduct the 12v applied to the coil (because it's back-biased) but will conduct the discharge current (when power is removed) to let the coil discharge the stored field gracefully. That's fine unless that diode fails as a short (as yours may have done), effectively providing a short across the SS pull coil.

Wow! I found an EX manual (free online if anyone is interested; as well as CK, DK, & LX) and it is MUCH better than the DK45S service manual that I have! According to this manual, the stop solenoid relay is the right most relay on the firewall (as you face the firewall). Do you think this is correct for the DK45S?s...

Kioti changed engines on all their tractors between 2005 and 2008; different times for different models (I guess when the old engines ran out). The old engine used an external stop solenoid that operated the manual stop linkage. The new engines used a stop solenoid on the front of the engine that pushed directly on the IP rack inside the block. I hasten to add that this new SS configuration had a high IP failure rate (broken gear teeth) for the first few model years.

The only available DK45S/451 service manual shows the old engine. If Kioti hasn't updated this manual by now, they never will. Other than that, the 451 manual is correct for your tractor. But for the engine (and engine-related stuff) look at the EX manual. The newer manuals are much more complete and explain things better (the original DK manual is truely awful). But all manuals have numerous errors and omissions, I think. For example my DK45S has several grease fittings which are not shown in the manual.

By the way, I think the 45s and 55s may be Kioti's best tractors. They very strong, heavy, and lack all the silly emission stuff (and cost-saving changes) on the new ones

 

[chuck172]

hey chuck... i just PMed you...

Thanks Billboe, very nice of you.

 

[Jim in NB]

Hi Everyone! A bit late on this one but I had a lot of trouble with Stop Solenoid (Ignition Relay) on my tractor. Original realy had 20A and 30A contacts in it. The replacement relay from the dealer now has 30A and 40A contacts in them now. This relay is a standard 5 pin automotive type relay available at any automotive supply house. Going to a 30/40A relay seemed to have solved my problem. I also changed the relay on the right (facing rear of tractor from the front) which the manual calls the Engine Stop Relay to a 30/40 relay as well. Neither relays have failed since the change over.

My next project seems to be the middle relay (Preheat Relay) as with the cooler mornings this time year I dont seem to have working glow plugs. The engine turns over fine but it takes a lot of cranking for it to fire. In the past just letting the glow plug indicator light go thru the 10 or so second time cycle the engine fired right away. Any ideas?

 

[ritcheyvs]

... Any ideas?

Try squirting some WD40 or (even batter) electrical contract cleaner in the key hole. Then cycle the key several times. Not sure why this works but it worked for me.