Kubota SVL90-2 no power under load and producing black smoke under load.

[Tags]

Looking for some help on this…So we have a Kubota SVL90-2 with about 2300 hours on it that we have owned since new and has had all the scheduled maintenance performed on it . Showing no codes, plugged it in to check for codes and there are none. Machine runs fine until it is under a load (trying to load the bucket, carrying heavy load on the forks, trying to drive up a steep incline, etc) when its under by a load it produces black smoke, not thick, but enough that it has turned the exhaust pipe and the back of the machine black. We have replaced the air cleaners, changed the fuel filters, and found no blockages in the air intake, we have also checked the turbo, no excessive oil or loose. Anyone come across this before? Any help would be appreciated.

 

[bobatack]

maybe check the piping between turbo and engine intake for leaks/holes or maybe it even came apart somewhere

 

[thepumpguysc]

Run it without the air cleaner and air box or take the filter out and leave it open and try it.

 

[Tags]

Run it without the air cleaner and air box or take the filter out and leave it open and try it.

We did that too. Didn’t make a difference.

 

[thepumpguysc]

I suggest plumbing in a boost gauge to check turbo boost..
What altitude are you at.??
Any chance THAT is having any effect on your engine.??

 

[Tags]

Thing has been fine until a couple of days ago. Will have to try a boost gauge next.

 

[KSSS]

sounds like turbo to me

 

[Tags]

Thanks for all the replies. Just to be clear, it is fine black dry soot coming out of the exhaust, not oily or wet at all.

 

[thepumpguysc]

Seeing it’s a common rail fuel system.. the computer would regulate the fuel.. unless something went wrong in the pump but u would have to access the diagnostic port..??

 

[Tags]

Yes. We have the ability to plug in to read codes and we are getting none. Really strange that it’s not showing any issues.

 

[ozarkag]

Monitor boost while under load. Either plug in with diag tool or plumb in Guage

 

[Tags]

Sooooooooo. We had a bad injector. Disassembled, removed all injectors and had them tested. One was bad. Replaced, reassembled, programmed new injector. Same issue.

I can not believe how much needs to be disassembled to get to the injectors. Plenty of fuel and pressure according to the diag computer.

 

[ozarkag]

I can not believe how much needs to be disassembled to get to the injectors. Plenty of fuel and pressure according to the diag computer.

Yeah, and people wonder why so expensive.

Did you check boost readings? Should be able to gain approx 10 psi at full throttle and under load. Loading the engine with the hydraulics should be enough. A rather common problem is the intake manifold breaking where the exhaust mounts to the aluminum intake manifold.

 

[Tags]

Thank you for that.

 

[Tags]

Yeah, and people wonder why so expensive.

Did you check boost readings? Should be able to gain approx 10 psi at full throttle and under load. Loading the engine with the hydraulics should be enough. A rather common problem is the intake manifold breaking where the exhaust mounts to the aluminum intake manifold.

So plugged in a checked boost. Fine when cold, as soon as it warmed up a little fell flat on its face as it has been. Got down to looking at the intake. Cracked, just as you said, and a large chunk that was cracked as well. The chunk was loose and we pulled it out wasn’t found like the pic. Thanks to everyone for the help sorting this out, I really appreciate it!

 

[ozarkag]

Thanks for coming back and posting that. Does look familiar. We have tried to come up with a better mount for the DPF/ muffler but hardly anywhere to bolt to. Did have one deleted one come thru where we simply removed the DPF entirely and installed a light muffler.