D750 smoking

[Bill 2]

I have a Bobcat mini excavator with a D750 in it. Originally motor was super hard starting and smoked when i got it running and had no power. I did a compression test on the one cylinder that I could get the tool on and it was low. Doing a compression test on all the other two cylinders is impossible due to the angle while they're in the machine.
I sent the cylinder head out to be rebuilt, (came back with no major concerns) put on new piston rings, installed new injectors and reassembled it. It's still very hard starting and while cranking, billows out a ton of dark grey smoke until it finally catches and then smoke diminishes from the exhaust but doesn't completely disappear. I have some blow by, not a lot, but still more than I think it should have. The machine now actually has power. I still hear a little chattering so I think the valves need to be adjusted a little more.
Does this sound like a fuel issue because of the hard starting? or does this sound like something else? Suggestions welcome and appreciated. Thanks

 

[cthomas]

Did you replace the glow plugs and verify they are working? Also if the valves need adjustment, do that before guessing at other issues. Did the cylinder walls still have cross-hatching and piston appear to be smooth and round?

 

[Bill 2]

Did you replace the glow plugs and verify they are working? Also if the valves need adjustment, do that before guessing at other issues. Did the cylinder walls still have cross-hatching and piston appear to be smooth and round?

Haven't checked the glow plugs - since it's been so hot I didn't think they would make a difference. The pistons and cylinders were fine. I'll adjust the valves and see if that helps. Thanks

 

[North Idaho Wolfman]

Need to have the injectors rebuilt or replaced.
Oregon fuel injection: https://www.google.com/url?sa=t&sou...wQFnoECDkQAQ&usg=AOvVaw3CEa4iGk34juSqkXNyZYai

Also the engine uses the glow plugs all the time to start, cold or warm.

Might even need to rebuild or replace the injection pump.
But save that for last!

 

[Bill 2]

Need to have the injectors rebuilt or replaced.
Oregon fuel injection: https://www.google.com/url?sa=t&sou...wQFnoECDkQAQ&usg=AOvVaw3CEa4iGk34juSqkXNyZYai

Also the engine uses the glow plugs all the time to start, cold or warm.

Might even need to rebuild or replace the injection pump.
But save that for last!

Didn't know that - thank you.

 

[BillL47]

Need to have the injectors rebuilt or replaced.
Oregon fuel injection: https://www.google.com/url?sa=t&sou...wQFnoECDkQAQ&usg=AOvVaw3CEa4iGk34juSqkXNyZYai

Also the engine uses the glow plugs all the time to start, cold or warm.

Might even need to rebuild or replace the injection pump.
But save that for last!

+1 Poor atomization, timing, low pop pressure of nozzles can cause "white" smoke. It actually is unburned fuel, and if combined with a little black smoke, it looks gray. Make sure your fuel pressure into the inbection pump is not too low (good filter), and if the nozzles alone don't get the job done, then consider the pump for servicing. While the scroll injection pumps are pretty bullet proof poor quality fuel(foul) or water can destroy the internals.

Since diesel power is determined by the injection per stroke, if the filter is restricted/plugged, or injection housing pressure is low the injection pumps will not fill and result in low power.

You will get it fixed!!

 

[cthomas]

Are the new injectors from Kubota or Bobcat? As I have had issues with auto part store injectors. Granted this was in a Silverado, but, diesel engine is a diesel engine.