Stumped....D902 issue

[lugbolt]

Kubota BX23S. D902 10 hours on the hour meter. Was running fine, guy says it was vibrating a little more than "normal", but he wrote it off as perhaps being used a little harder and lugging the engine more. Parked tractor inside the garage. Next morning, gets back on tractor and starts the engine. Engine is smoking, he loaded it up & brought it to me.

Engine indeed smokes. Fuel smoke only. Oil level was a little on the high side, maybe from the dead miss on #1 cylinder? Runs on #3 and #2 cylinder. #1 cylinder is a dead miss, which is also the source of the exhaust fuel smoke. Crack #1 injector while running, smoke disappears. Removed exhaust manifold, verified fuel smoke from #1 cylinder only (the REAR cylinder...since the engine is mounted in the tractor backwards). 560 psi on all 3 cylinders. Valve clearance within specification. Replaced #1 injector, no change. Removed injection pump, installed a known good pump (verified exact same part number via dealer) and again, no change. Removed intake manifold thinking maybe it's got a blockage, none found. Everything's as clean as a 10 hour engine should be.

Also removed all fuel with the thought that it had a completely full tank, maybe it had some water or other nastiness in it (did not find anything)....replaced with known good fresh fuel, no change whatsoever.

I'm stumped. Y'all got any suggestions?

 

[North Idaho Wolfman]

As odd as it may sound, run a wire through the injection line and make sure it's clear, low pressure from a blockage can cause it to not pop right.

Also, wouldn't be the first time I've heard of a bad injector, swap injector see if problem moves.

 

[lugbolt]

As odd as it may sound, run a wire through the injection line and make sure it's clear, low pressure from a blockage can cause it to not pop right.

Also, wouldn't be the first time I've heard of a bad injector, swap injector see if problem moves.

Replaced injector initially, then swapped them around and the problem stayed with #1 cylinder. Haven't tried the line yet but I did blow through it and it seemed to be clear. I'll run a wire through it...may be some paint inside or something.

 

[North Idaho Wolfman]

Replaced injector initially, then swapped them around and the problem stayed with #1 cylinder. Haven't tried the line yet but I did blow through it and it seemed to be clear. I'll run a wire through it...may be some paint inside or something.

It is a real odd one, just about everything you have done I would have.

Oh do a fountain test on the pump outputs, maybe a flat fuel cam?

 

[100 td]

If the valves are fully opening, (worth checking the inlet manifold for a restriction, haven't got a rat stuck in there hey?) and you also have 560 psi, surely it's gotta be a bit of crap or line like NIW suggested or a bad injector.
Got any measuring cylinders?
Spin the lines around and tie a cylinder onto each injector and do a measure, check spray while you have them turned. I can't see a flat fuel cam in 10 hours when it was running correctly before?

 

[07wingnut]

Any developments on this? It's one of the most intriguing problems yet reported on this board.

 

[lugbolt]

Any developments on this? It's one of the most intriguing problems yet reported on this board.

Not yet. Worked with tech support today and they've given me some more ideas to look into as far as timing, etc; but haven't had the chance to dig back into it yet.

 

[lugbolt]

Tech support suggested checking the injection timing. Did, and oddly, found it to be off (retarded). Removed shims to correct it and it got a LOT better, indicating that SOMETHING is going weird with the #1 cylinder. That's as far as I got; had a boat load of broken lawn mowers show up and of course everyone needs them the day before yesterday or the world will come to an end. Back to the BX tomorrow-hopefully. I think I'm going to pull the cylinder head and have a look at the valve seats and prechamber, with a hunch.

 

[lugbolt]

Pulled engine apart and found that the crankshaft is broken. Spoke with customer some more and he said that he ran engine out of fuel prior to it coming to me; and said he had been using starting fluid to start the engine because obviously it wouldn't start with air in the fuel system.

....A $3 can of starting fluid + ignorance is going to cost this guy about $6000.

 

[D2Cat]

But Lugbolt, I just used a spritz, and I sprayed it right into the intake so I'd know it was going in the engine....and it started every time when I used it!

(tongue in cheek!)

 

[whitetiger]

Too bad Kubota does not put fuel level gauges on their tractors to monitor how much is in the tank.

 

[North Idaho Wolfman]

All I can say is WOW!
What a sad end for a perfectly good engine!

 

[100 td]

Like everything, when used incorrectly, bad results. I think the advertising of the product is to blame for the damage by the masses that use the stuff.
Where's the pics lugbolt?

 

[OrangeRidge]

Pulled engine apart and found that the crankshaft is broken. Spoke with customer some more and he said that he ran engine out of fuel prior to it coming to me; and said he had been using starting fluid to start the engine because obviously it wouldn't start with air in the fuel system.

....A $3 can of starting fluid + ignorance is going to cost this guy about $6000.

Good grief ! It's better to give the engine a crank-over after 10 seconds of heater plug , and crank until it fires . The fuel pump will have the diesel to the injector pump by battery power only . A dry engine is no drama until stupidity strikes ............

 

[ya472]

Pulled engine apart and found that the crankshaft is broken. Spoke with customer some more and he said that he ran engine out of fuel prior to it coming to me; and said he had been using starting fluid to start the engine because obviously it wouldn't start with air in the fuel system.

....A $3 can of starting fluid + ignorance is going to cost this guy about $6000.

Crankshaft is broken, like severed? Isn't #1 cylinder on waterpump end, driving the HST? Wouldn't you notice a problem when adjusting valves? Just saw this and curious.

 

[Henro]

Crankshaft is broken, like severed? Isn't #1 cylinder on waterpump end, driving the HST? Wouldn't you notice a problem when adjusting valves? Just saw this and curious.

I am having trouble understanding this situation too.

Lugbolt, you mentioned the engine was running when evaluating it, after the issue appeared...is this feasible with a broken crankshaft?

Is there a chance that the use of starting fluid had nothing to do with the initial failure, which could be a broken crankshaft. Then if a broken crankshaft occurred first, it would just be an assumption that starting fluid caused the issue. Starting fluid may have caused nothing after the fact.

Just puzzled because I have heard many times about using starting fluid causing bent connecting rods...but never a broken crankshaft. Maybe broken pistons too...but a crankshaft?

 

[RCW]

Well, it was an issue in 2018. Hopefully resolved by now.

 

[Henro]

Well, it was an issue in 2018. Hopefully resolved by now.

Yikes!!!

I hate it when I’m sucked into these old threads that I think are current!

BX23S is still a current model I believe. So no hint there. But Lugbolt doesn’t work at a Kubota dealer anymore. That was a question in the back of my mind, but it did not register.

 

[fried1765]

Yikes!!!

I hate it when I’m sucked into these old threads that I think are current!

BX23S is still a current model I believe. So no hint there. But Lugbolt doesn’t work at a Kubota dealer anymore. That was a question in the back of my mind, but it did not register.

Yup.....
Only 5 days short of being 5 years, since recent response!

 

[North Idaho Wolfman]

FYI: It is very possible for an engine to keep running with a broken crank, most of the time it's a cross break and the crank is still locked together.
I've seen it on a couple old v8 engines.