DK45SC Starting problems

[jimglassford]

Thanks for the suggestions and speculations. My 2006 DK45 has the lever by the solenoid...I always wondered what it was for! I have a few things to try out. The past few times I've started the tractor, I've pumped the plunger on top of the fuel filter 8 or 10 times and the engine started on the first try (this may or may not be related, given how intermittent the issue has been in the past.
Finally, jimglassford, is your fuel tank below the engine, then? Mine is on top of the engine just forward of the firewall.

As others have pointed out, the engine stop mechanisms could be causing the issue but since you can use the priming system to help start the tractor, I would think you have a fuel issue outside of the fuel injection pump.

My tanks are under the platform and thus requires a lift pump to bring the fuel up to the engine. I believe I have solved my starting issue this week. I purchased my DK55 tractor used and the previous owner, a landscape supply yard, had a real bad diesel mechanic. My tractor showed the same symptoms as your DX45SC. Whether the tractor was cold or warm, I had to crank it a long time to get it to start. If I pumped the primer a number of times, it would start immediately. I had to pump the primer until I heard the fuel return to the fuel tank. This pointed to the fuel delivery system. I took the lift pump off of the tractor, disassembled the unit and wiped down the diaphragm, valves and internal body. I then checked all hoses for cracks at the ends where they fit over the metal nipples at the pump and filter. I replaced the adjustable hose clamps with actual spring fuel line clamps. I am not a big fan of adjustable hose clamps on small diameter hoses, they distort the hose as it clamps.

Over the past few days, I have tried starting the tractor when it is cold and when the tractor is warm, after shutting down and sitting for 20 to 30 minutes. It now starts each time. I believe the issue was that when the tractor was sitting, the fuel slowly drained out of the lift pump.

The DK45SC does have the fuel tank mounted in the bonnet. However, there is a fuel lift pump (item 19 in the diagram). I was trying to find a diagram of the fuel tank to see if the DK45SC fuel tank pulls fuel out of the top or bottom of the tank. Since you can pump the primer and then the tractor starts, you may have a fuel leak or an air leak that is removing the fuel from the fuel line. Cranking the engine for a while allows the lift pump to refill the system that feeds the fuel injection pump.

View attachment 673288

There is still the possibility of a shut off system issue. You have the integrated fuel shutoff solenoid and an external cable operated shutoff. Make sure the cable pull shut off is fully forward when you try to start the tractor. There is also the possibility that the integrated solenoid is getting hydraulically locked if oil is getting into the solenoid. However, your analysis of pumping the primer a number of times then the tractor starts still points to a fuel system leak emptying the fuel line.

 

[Kioti Paul]

As others have pointed out, the engine stop mechanisms could be causing the issue but since you can use the priming system to help start the tractor, I would think you have a fuel issue outside of the fuel injection pump.

My tanks are under the platform and thus requires a lift pump to bring the fuel up to the engine. I believe I have solved my starting issue this week. I purchased my DK55 tractor used and the previous owner, a landscape supply yard, had a real bad diesel mechanic. My tractor showed the same symptoms as your DX45SC. Whether the tractor was cold or warm, I had to crank it a long time to get it to start. If I pumped the primer a number of times, it would start immediately. I had to pump the primer until I heard the fuel return to the fuel tank. This pointed to the fuel delivery system. I took the lift pump off of the tractor, disassembled the unit and wiped down the diaphragm, valves and internal body. I then checked all hoses for cracks at the ends where they fit over the metal nipples at the pump and filter. I replaced the adjustable hose clamps with actual spring fuel line clamps. I am not a big fan of adjustable hose clamps on small diameter hoses, they distort the hose as it clamps.

Over the past few days, I have tried starting the tractor when it is cold and when the tractor is warm, after shutting down and sitting for 20 to 30 minutes. It now starts each time. I believe the issue was that when the tractor was sitting, the fuel slowly drained out of the lift pump.

The DK45SC does have the fuel tank mounted in the bonnet. However, there is a fuel lift pump (item 19 in the diagram). I was trying to find a diagram of the fuel tank to see if the DK45SC fuel tank pulls fuel out of the top or bottom of the tank. Since you can pump the primer and then the tractor starts, you may have a fuel leak or an air leak that is removing the fuel from the fuel line. Cranking the engine for a while allows the lift pump to refill the system that feeds the fuel injection pump.

View attachment 673288

There is still the possibility of a shut off system issue. You have the integrated fuel shutoff solenoid and an external cable operated shutoff. Make sure the cable pull shut off is fully forward when you try to start the tractor. There is also the possibility that the integrated solenoid is getting hydraulically locked if oil is getting into the solenoid. However, your analysis of pumping the primer a number of times then the tractor starts still points to a fuel system leak emptying the fuel line.

My DK45SC has the tank in the bonnet, the bottom of the tank is above the engine driven fuel pump (not sure I would describe it as a lift pump) The fuel tank outlet is at the bottom of the tank, and the fuel line runs downhill to the pump; Any leaks between the tank and the pump would have fuel leak out (not air leaking in). From the pump, the line does run uphill to the fuel filter, but even the top of the filter is below all but the bottom 1/4 of the tank. As long as you have at least 1/2 tank, I do not know how you could get an air bubble in my particular setup. Also, the 'plunger' that sits on top of (my) fuel filter is not a primer pump (per se); it is an air bleed.

 

[jimglassford]

My Also, the 'plunger' that sits on top of (my) fuel filter is not a primer pump (per se); it is an air bleed.

According to the parts diagrams, you should have the following assembly as a fuel filter. The spring loaded plunger on top is a primer to move fuel through the system. The air bleeder is on the side of the casting.

View attachment 673317

 

[LouNY]

On some primer pumps it was required that the pump handle be pushed down and turned a quarter turn to lock it down,
otherwise it could allow air to be sucked in.
One other thought if you have a screen in the outlet of the tank and it is getting restricted you could suck air into the system from any joint.

 

[rd_macgregor]

My fuel filter unit looks exactly like the one jimglassford posted. I think the pump on the top helps bleed air out when the air bleed gadget is open, but primes when it is closed. My fuel supply system is pretty much all lower than the fuel tank, so any leaks shouldn't let air into the system...I don't see a mess of fuel leakage anywhere, either. Can relays and solenoids misbehave intermittently? Since the tractor runs well once I get it started, I don't think fuel contamination or plugged filters will be the problem. A glitchy relay or solenoid could act like this, though. I hate the way Kioti seemed to relocated relays from year to year; it is hard to trace wires to the correct relay!
Bob

 

[rd_macgregor]

Also, I have never yet had the tractor start at the end of a long crank; it either starts right up, or not at all. It may take a few tries, with filter priming in between to get it to fire, but when it does start it is right away after the key is turned to engage the starter...I don't know if this is relevant, but that has been my experience...and, again, I don't know if the priming is relevant either, maybe the tractor just wants a certain number of tries before it is willing to go!

 

[LouNY]

If the fuel flow is restricted some where any place after the restriction can leak air in and not show a fuel leak.
The injection pump will pull a vacuum once running.

 

[Kioti Paul]

Also, I have never yet had the tractor start at the end of a long crank; it either starts right up, or not at all. It may take a few tries, with filter priming in between to get it to fire, but when it does start it is right away after the key is turned to engage the starter...I don't know if this is relevant, but that has been my experience...and, again, I don't know if the priming is relevant either, maybe the tractor just wants a certain number of tries before it is willing to go!

After the end of a "long crank" do you leave the ign switch on the "run" position; or do you turn the ign switch "off"?

Although I asked it before (post 15), and you have never answered, I am forced to ASSume you are turning it "off" between crankings, which will "reset" the "stop solenoid timing relay" / which leaves only the "solenoid timing relay", the "solenoid relay", or the "fuel solenoid" as being your culprit. Of those 3 things, the "solenoid relay" is BY FAR the most likely.

If you can confirm that you do turn the switch off between crankings (and if you want me to),,, I can (try) to explain how to narrow down which of those 3 are bad, using a test light, or a VOM

 

[rd_macgregor]

Kioti Paul, ordinarily I would turn the ign all the way off before starting another cranking round. However, after you suggested it, I tried it both ways and didn't see any difference.
In any case, tonight things went from bad to worse! Without any priming or anything, the tractor started right up, however when I started to drive off, the tractor faded and died. When I went to restart it, it fired right up then went full throttle (scary!!). Shutting off and removing the key made no difference, so I went out to use the rack lever next to the solenoid...the rack lever wouldn't budge! Finally, I managed to get a fuel line off and the engine starved.
Whatever the original starting problem may have been caused by, I think I definitely now have a "shop" issue way, way beyond my competence to tackle.
Thanks to all for the hypotheses and suggestions.

 

[jimglassford]

It sounds like you have the common Kioti Injection Pump Failure. DO a forum search before you take it in. The Kioti Dealer can only replace the pump and that is huge money.