Kubota D1402 engine missing

[Junkytreasure]

Hey all, new guy here. I was hoping to get some help. I have an old mustang skid loader with a D1402 in it. I’ve owned this for several years and up until now it has been a great machine. Recently it has started sputtering at mid throttle. (Which is where I like to run it most of the time) it idles great and smooths out at WOT. Although I suspect it’s still missing, it’s just running fast enough that I can’t really tell. It had a 100 psi difference between cylinder 2 and 3 at the beginning which led me to pull the head for inspection. I did not find a single thing out of place there so I replaced the head gasket and put it back together. Now all 3 cylinders have around 350 psi. (Previously 400,400,300) the new head gasket was noticeably thicker. I think that brought compression down a bit. I have also pulled the injectors and swapped cylinders, I’ve even swapped the injector pump around. I moved everything for number 1 to number 2 and vice versa. Replaced the lift pump, measured the injector pump cam lift, and ran the valves… it still seems to be missing on number 2. I cracked the injector on number 2 and it doesn’t make any difference to the engine at mid throttle. And if loaded it sputters until the load is relieved. This problem is not intermittent or time dependent. You can run it for hours or start from dead cold, it still sputters under load and misses at mid throttle.

I’m quite sick of looking at it. Does anyone have any ideas or thoughts on things I may have over looked? I’m certain I didn’t list some things I’ve tried. I not a pro by any means, but I’m not a total newb either, I’m just stumped.

Thanks for sticking it out if you made it to here!

 

[North Idaho Wolfman]

So you pulled the injection pump apart and swapped parts internally around?

I would do a compression test again if its been running for a bit.

Did you use a Kubota OEM head gasket or Aftermarket?

Did you happen to do a piston height test when you had it apart?

 

[Junkytreasure]

Yes, I pulled the entire pump apart and inspected everything. It all looked good. So I swapped 1 and 2 for troubleshooting. The problem stayed at number 2.

2nd compression test was done today. I’m pretty sure it was an aftermarket head gasket.

I didn’t do a height test but I did rotate it through a couple of times. All cylinders did come to the top of the deck but I did not check them with a gauge. All cylinders were fairly tight in the bore, I didn’t see any extreme wear or damage either.

 

[PaulL]

It sort of has to be injector related, surely? But if you've swapped injectors that should rule that out. Fuel rail blockage of some sort?

 

[North Idaho Wolfman]

It sort of has to be injector related, surely? But if you've swapped injectors that should rule that out. Fuel rail blockage of some sort?

There is no fuel rail on that model.

 

[North Idaho Wolfman]

Yes, I pulled the entire pump apart and inspected everything. It all looked good. So I swapped 1 and 2 for troubleshooting. The problem stayed at number 2.

2nd compression test was done today. I’m pretty sure it was an aftermarket head gasket.

I didn’t do a height test but I did rotate it through a couple of times. All cylinders did come to the top of the deck but I did not check them with a gauge. All cylinders were fairly tight in the bore, I didn’t see any extreme wear or damage either.

How did you adjust or test the injection pump?
And swapping parts on a pump is a really, really bad idea, as each part needs to be tuned to work together.
Are you sure you clocked the rack and delivery valves the same?

I personally would retest the compression, if it's in line, then send the pump and the injectors to be tested and rebuilt.

If it's low, yet all cylinders are the same or close, I would get an OEM head gasket.
install and recheck compression, then send the injectors and Injection pump to be tested and rebuilt.

 

[Junkytreasure]

How did you adjust or test the injection pump?
And swapping parts on a pump is a really, really bad idea, as each part needs to be tuned to work together.
Are you sure you clocked the rack and delivery valves the same?

I personally would retest the compression, if it's in line, then send the pump and the injectors to be tested and rebuilt.

If it's low, yet all cylinders are the same or close, I would get an OEM head gasket.
install and recheck compression, then send the injectors and Injection pump to be tested and rebuilt.

I moved all of the parts together. As in, all mating parts from one to the other. Everything was kept clean and separated for their respective cylinders. I’m quite certain they are on the rack correctly. They have a sort of timing mark on them. As far as testing the pump all I can really do is verify a good injector spray pattern into open air and adjust the pump to give a consistent exhaust gas temperature between the three cylinders.

 

[Junkytreasure]

I have some cleaning up to do with it tomorrow. I think I’ll pull it in the shop and tear down when I’m done with it this weekend and put another head gasket in it. I don’t like that I lost compression on 2 cylinders. The head gasket is a pretty easy swap on that engine.
I was really trying avoid the $1000 rebuild fee, which seems pretty ridiculous to me considering what’s inside them.

 

[North Idaho Wolfman]

I moved all of the parts together. As in, all mating parts from one to the other. Everything was kept clean and separated for their respective cylinders. I’m quite certain they are on the rack correctly. They have a sort of timing mark on them. As far as testing the pump all I can really do is verify a good injector spray pattern into open air and adjust the pump to give a consistent exhaust gas temperature between the three cylinders.

Well it does sound like you've got a handle on it all.
Have you checked glow plugs?
And when you pull the head measure the rise of all the pistons.

 

[lynnmor]

I have some cleaning up to do with it tomorrow. I think I’ll pull it in the shop and tear down when I’m done with it this weekend and put another head gasket in it. I don’t like that I lost compression on 2 cylinders. The head gasket is a pretty easy swap on that engine.
I was really trying avoid the $1000 rebuild fee, which seems pretty ridiculous to me considering what’s inside them.

I would freshen up the valves and seats to make sure that they are OK.

 

[Junkytreasure]

I would freshen up the valves and seats to make sure that they are OK.

Not a bad idea at all. I did give them the ol flashlight test when I had it off last time. I was kind of kicking myself for not going ahead and breaking the head down and actually looking at the valves and whatnot after the new head gasket didn’t fix it.