(Fixed info) D1105T rough running, smoking under heavy load

[NickP178]

Hello All,
New here, but been lurking for a while trying to figure out a couple of problems with my D1105T. Decided to join and hopefully add a little information to the mix.
A little background: I have a New Holland CM272 rear-engine commercial tractor with a Kubota D1105T engine swap (Professionally rebuilt engine out of a Jacobsen golf course Reel Mower) which serves as my business parking lot snow removal beast.
It has run beautifully for the past four seasons, but showed a slight miss at lower RPM's when I started it this fall to get it ready for the winter. Seemed to run and perform OK for the first few storms, but fell on its face under heavy load with the snowblower operating (blowing black and white smoke, running rough, stalling and hard to restart.)
Pulled the intake hose off and found the cold side turbo impeller loose (nut on turbo cartridge had loosened). Pulled the center assembly and found a small piece of debris in the hot side housing that had impacted the turbine wheel. Looked like a small piece of intake valve seat, So I pulled the head off to check the valve seats and found absolutely nothing wrong. (Assuming at this point that this was damaged valve seat debris from the original failure that was lodged in the hot side casting leading up to the rebuild: Reel mower was driven into a water hazard at the golf course, hydro-locked with broken connecting rods and more).
Replaced the turbo with a new OEM Mitsubishi TD025 and new top end gaskets. Seemed to run pretty well and had good power until under load blowing snow. I noticed that when it ran rough and stalled out, that when I primed the injection pump afterwards there was air coming out of the line from the IP to the return line at the injectors.
Long story short, I pulled the injectors and had a local Diesel shop test them. They all pop tested OK at first, but when they disassembled them to clean them, they noticed that one injector had a sticking pintle valve when trying to remove it from the injector body. Intermittent sticking open of the pintle was allowing combustion gas to backfeed into the injection pump.
Rebuilt all three injectors and problem is solved.
Hope this helps somebody with any weird issues they might be encountering.

Regards,
Nick

 

[North Idaho Wolfman]

As I was reading I was thinking injector issue, Glad to hear you got it figured out and running right!

 

[Nicksacco]

Hope this helps somebody with any weird issues they might be encountering.

Regards,
Nick

Nice write up Thank you

 

[fried1765]

Hello All,
New here, but been lurking for a while trying to figure out a couple of problems with my D1105T. Decided to join and hopefully add a little information to the mix.
A little background: I have a New Holland CM272 rear-engine commercial tractor with a Kubota D1105T engine swap (Professionally rebuilt engine out of a Jacobsen golf course Reel Mower) which serves as my business parking lot snow removal beast.
It has run beautifully for the past four seasons, but showed a slight miss at lower RPM's when I started it this fall to get it ready for the winter. Seemed to run and perform OK for the first few storms, but fell on its face under heavy load with the snowblower operating (blowing black and white smoke, running rough, stalling and hard to restart.)
Pulled the intake hose off and found the cold side turbo impeller loose (nut on turbo cartridge had loosened). Pulled the center assembly and found a small piece of debris in the hot side housing that had impacted the turbine wheel. Looked like a small piece of intake valve seat, So I pulled the head off to check the valve seats and found absolutely nothing wrong. (Assuming at this point that this was damaged valve seat debris from the original failure that was lodged in the hot side casting leading up to the rebuild: Reel mower was driven into a water hazard at the golf course, hydro-locked with broken connecting rods and more).
Replaced the turbo with a new OEM Mitsubishi TD025 and new top end gaskets. Seemed to run pretty well and had good power until under load blowing snow. I noticed that when it ran rough and stalled out, that when I primed the injection pump afterwards there was air coming out of the line from the IP to the return line at the injectors.
Long story short, I pulled the injectors and had a local Diesel shop test them. They all pop tested OK at first, but when they disassembled them to clean them, they noticed that one injector had a sticking pintle valve when trying to remove it from the injector body. Intermittent sticking open of the pintle was allowing combustion gas to backfeed into the injection pump.
Rebuilt all three injectors and problem is solved.
Hope this helps somebody with any weird issues they might be encountering.

Regards,
Nick

Thank you for your contribution Nick!

 

[Vigo]

Thanks for posting that. Gotta admit i never really stopped to wonder what would happen if a leaking injector allowed combustion pressure to backfeed towards the pump. I know combustion pressure is way less than injection pressure but I dont have my head all the way around what happens in the injector line after the poppet is supposed to close..

I imagine the pump element is riding back down in its little cylinder and the pressure between the injector and the pump drops a whole bunch. If the injector were leaking it would allow combustion pressure to push partially burned gases into the line. That would make the next injection event crappy because since some of what was in the line was gaseuous, it would compress a whole bunch before making enough pressure to open the injector, and then what ended up being injected would be part fuel and part unburnable endgases, AND it would be way late on timing so that cylinder would run like shit, barely better than a dead miss, and lots of abnormal smoke.. Yep, that all checks out.. just never thought it through before. Now i feel like a marginally better mechanic. Thanks for putting that case study in front of us!