Kobelco sk210-lc8 pouring black smoke

KevinArmentrout · May 4, 2016

Hello everyone.

I'm hoping some of the expertise on this forum can help me. I am having issues with my kobelco sk210 lc-8 POURING black smoke when it's under load. Only under load. I can rev it high and it's fine, but as soon as I lift the boom or perform any function with the controls it pours black smoke. Here's what we have done so far to troubleshoot:

A little history: We had it at a friends house and it was running fine. We had a blizzard with about 2 foot of snow. Long story short, after the snow melted, we went to move it. about 20 feet and it died. After a fuel pump replacement and filters, we came to find out the entire Lower fuel filter housing was completely packed full of mud. So after all that was cleaned up it was running great...probably put 50 more hours on it....Then we moved it to a new job and noticed it was slowly losing power and more black smoke, so we stopped running it. Replaced the filters again and then took the fuel tank off and scraped a significant amount of smelly mud and random parts that didn't belong in the tank. Didn't help.

First thing that came to our minds was not enough air and too much fuel.....

* First we checked for dirty air filters. Ran the machine without them for a quick test. Not the problem. However from sitting a mouse had built a nest in there... and to my luck when I had my head down in the engine, ol jake the snake decided to come out. I about did a back flip off the counter weight lol.
* We disconnected innercooler lines, etc.. to make sure no restriction was in the lines.
* Rebuilt the turbo. Noticed a little oil leaking past the seals, and turbine had too much play for our liking. So nice rebuilt turbo.
* Took the little heater off on top of the engine and that was fine.
* cracked each injector line to see if they affected the engine. All injectors seemed to perform as they should.
* Blew out all of the fuel lines after disconnecting all of them.

The only thing left that we can think of is the injection pump, so we took that off, then we called B&D diesel and they said to put it back on and it didn't sound like the pump. It sounded like loss of fuel????????? And try to bypass all of the lines by hooking up a jug of diesel fuel and a line straight to the injection pump.... Thunderstorms limited our work yesterday so were going to try that this week.

The engine is a CNH or IVECO... There is a CNH tab right on top of the motor..
Anyone have any ideas? And no we havn't purchased a service manual yet..... it's coming though.:Banghead

KevinArmentrout · May 5, 2016

KevinArmentrout said:
Hello everyone.

I'm hoping some of the expertise on this forum can help me. I am having issues with my kobelco sk210 lc-8 POURING black smoke when it's under load. Only under load. I can rev it high and it's fine, but as soon as I lift the boom or perform any function with the controls it pours black smoke. Here's what we have done so far to troubleshoot:

A little history: We had it at a friends house and it was running fine. We had a blizzard with about 2 foot of snow. Long story short, after the snow melted, we went to move it. about 20 feet and it died. After a fuel pump replacement and filters, we came to find out the entire Lower fuel filter housing was completely packed full of mud. So after all that was cleaned up it was running great...probably put 50 more hours on it....Then we moved it to a new job and noticed it was slowly losing power and more black smoke, so we stopped running it. Replaced the filters again and then took the fuel tank off and scraped a significant amount of smelly mud and random parts that didn't belong in the tank. Didn't help.

First thing that came to our minds was not enough air and too much fuel.....

* First we checked for dirty air filters. Ran the machine without them for a quick test. Not the problem. However from sitting a mouse had built a nest in there... and to my luck when I had my head down in the engine, ol jake the snake decided to come out. I about did a back flip off the counter weight lol.
* We disconnected innercooler lines, etc.. to make sure no restriction was in the lines.
* Rebuilt the turbo. Noticed a little oil leaking past the seals, and turbine had too much play for our liking. So nice rebuilt turbo.
* Took the little heater off on top of the engine and that was fine.
* cracked each injector line to see if they affected the engine. All injectors seemed to perform as they should.
* Blew out all of the fuel lines after disconnecting all of them.

The only thing left that we can think of is the injection pump, so we took that off, then we called B&D diesel and they said to put it back on and it didn't sound like the pump. It sounded like loss of fuel????????? And try to bypass all of the lines by hooking up a jug of diesel fuel and a line straight to the injection pump.... Thunderstorms limited our work yesterday so were going to try that this week.

The engine is a CNH or IVECO... There is a CNH tab right on top of the motor..
Anyone have any ideas? And no we havn't purchased a service manual yet..... it's coming though.:Banghead

Update: we bypassed the fuel and hooked a jug of diesel to the injection pump. Same problem. Also it happens at idle and at full rpms but only when you activate the hydraulics fully. If you lift the boom gradually it doesn't do it as much. Any thoughts?

87silvert · May 6, 2016

Fuel being that contaminated sounds really bad, but I would think it would skip, white smoke, or misfire if that was the problem. You took care of the intake side of things, how about the exhaust?

KevinArmentrout · May 6, 2016

Yeah. It was pretty bad. But the good thing is the filtration on that machine. The bottom larger filter goes straight up to the fuel pump and then from the fuel pump back down to the second and third filter, then back to the injection pump. The smaller filters didn't have anything in them or the housings. So it looks like the large filter took one for the team. Yesterday we replaced the smaller filters just to weed that out.

Exhaust: We took the muffler off. We separated it from the turbo where that silver band clamp disconnects. Turbines spin freely.

It's odd. You can turn the throttle up and leave it there. Engine doesn't miss a beat. As soon as you pull back on the lever to raise the boom, black smoke fills the air and the rpm's drop down. If you pull back gradually though, it's not as bad.

Another thing that I don't quite understand is it does it at idle(under load) and at full throttle (under load). My assumption was it would be able to deliver enough fuel at idle under load more so than full throttle.

So the only thing I can think it would be is the injection pump or the injectors.... We also checked the air flow from the intake yesterday again. It puts out more air than my leaf blower!

KevinArmentrout · May 6, 2016

Thanks for your response btw! I was wondering if anyone was still on here lol

Delmer · May 6, 2016

Not enough air and too much fuel isn't as common as you'd think on a diesel, they run with such an excess of air usually. For the injection pump to be causing this the timing would have to have advanced a lot (unlikely?). The injectors could be leaking, you wouldn't think they'd all fail identically though?

All that leaves is that there is more load on the engine than there should be, how's the hydraulic system look? And does it act the same way hot and cold?

KevinArmentrout · May 6, 2016

Yeah I'm grasping for straws on this one. I wouldn't think the injectors would be bad. I would think there would be a miss or something, but maybe not. We haven't looked at anything yet on the hydraulic system. I think we will have to find a book before we start exploring that too much. I am under the same thinking though..... maybe some kind of hydraulic circuit or something.. Also no codes on the display except for incorrect hours on meter.... or something like that..

It performs the same way hot or cold btw

KevinArmentrout · May 10, 2016

Well, pulled the no. 1 injector out. Fairly dirty. Were just going to pull the rest and clean them and take some bore brushes and clean the cylinders.. If that doesn't fix the issue, the injection pump is the next step.

Delmer · May 10, 2016

If you're taking the injectors out, have them pop tested by an injection pump shop. Cleaning them won't do much, if anything. Same for the cylinders, cleaning just doesn't matter.

Have you sent in a hydraulic oil sample? or checked the filter for debris? it would stink to rebuild the injection pump and then find out the machine is junk because the hydraulic system is messed up. Some other things to test under load, boost pressure, fuel pressure going into injection pump, exhaust back pressure...

KevinArmentrout · May 10, 2016

Delmer said:
If you're taking the injectors out, have them pop tested by an injection pump shop. Cleaning them won't do much, if anything. Same for the cylinders, cleaning just doesn't matter.

Have you sent in a hydraulic oil sample? or checked the filter for debris? it would stink to rebuild the injection pump and then find out the machine is junk because the hydraulic system is messed up. Some other things to test under load, boost pressure, fuel pressure going into injection pump, exhaust back pressure...

10-4. Thanks Delmer. The injection shop told us to bring him the injectors and the pump, so yeah I'm assuming they are going to test them, but we were going to clean them and put them back to test, but if cleaning them doesn't really matter then, we can just take them up to the shop to have them pop tested. Wish I had the equipment to test them myself, but oh well.

I'm kind of new with the hydraulics. How does the hydraulics affect the engine blowing smoke? I've rebuilt cylinders and valve bodies, but never had to delve into hydraulic circuits and such and how it affects the engine.... We have not sent a sample anywhere yet or checked the filters. We were thinking strictly an engine issue...

Delmer · May 10, 2016

I'd bring the injectors in first, a lot easier and it doesn't look like you're in a remote location.

This is an odd problem, even so, I'm surprised at the lack of responses? A diesel lugging down and blowing black smoke just doesn't make too much sense. If the fuel is there then it should be making the power, UNLESS the fuel is too early because the timing is advanced (I don't know if that's even possible to fail that way?) or because the injectors are leaking under load. I don't know what kind of injection system this is, inline pump? common rail? The trouble you had with junk in the fuel makes you think it's fuel related, but it was 50 hours ago and you had two more filters in line to catch the original junk.

The hydraulic system malfunctioning is kind of a last resort, "what else could it possibly be" idea. If a pump isn't being controlled right, or possibly is leaking?, then it could use more power than it's designed to and cause the engine to lug and blow smoke.

Another thing to check is the intercooler and lines for leaks, that could cause black smoke and low power.

https://www.heavyequipmentforums.com/showthread.php?59109-CAT-320c-Hydraulics-stalling-engine This thread is one way hydraulics can stall the engine, his pump isn't turning off when the cylinder hits the end, and stalling the engine. Different than yours but you get the idea.

KevinArmentrout · May 11, 2016

Hey Delmer,

We pulled all the injectors yesterday. Took an old fuel rail and cut one of the fittings off, welded it to a slide hammer adapter and made a nice little tool to pull the rest of the injectors. They were dirty, but the spray pattern was correct on them. Were still going to take them to get pop tested. Runnin out of ideas buddy.. Last but not least... the injection pump. We were thinking about running an electric fuel pump to the inlet on the injection pump, but it's hard to rig a line up with the inlet being so big. We broke one of those fuel fittings with the retainer rings off. So now we have to track one of those down. As for the hydraulics, I would assume(ass-u-me) that being computerized, solenoids, etc... ECM would throw a code or something....The engine being mostly all mechanical I can understand why It would not.

I don't know if these would be legit tests or not but we were thinking:

1) we could pressure test the pump somehow
2) hook up a boost gague
3) take the injectors and pump to get tested.....
4) Lastly, light a match, and throw into tank..

P.S. I can't believe the lack of responses either. I thought maybe I was just PM'ing you back and forth and nobody else could see them lol!

Oh almost forgot... This is a common rail system. Very easy to pull apart the injectors and clean them.. The injection pump is a bosch.

Delmer · May 11, 2016

Only thing I know for sure is that you and I are over our heads...

You would think that a computer would throw a code in a situation like this, but if the right/wrong? sensor is acting up the computer won't know the difference. I've never heard of a mechanical common rail engine, out of my league

I will guess that the common rail system adds a few more possible explanations to the engine doing this without hydraulic malfunction.

lantraxco · May 11, 2016

Serial number? The early ones had Hino, later Tier 3 EPA units look like Cummins but definitely not common rail.

mikebramel · May 11, 2016

Does the problem go away when you change computer modes. Heavy, STD, light, etc

Colorado Digger · May 11, 2016

I had the same problem on my sk350 -8. It was the turbo.

Shimmy1 · May 12, 2016

You've removed air filters, checked piping, new turbo. Sounds like it's not air. I would stop messing with the fuel system, black smoke is lack of air, excess fuel, improper timing, or overload. If you haven't checked the piping between air filter and turbo, you need to do that. Also, between air filter and outside air. If that all checks out good, and you're certain you have pump timing correct, only thing left is the hydraulics. I don't know Kobelco, but I'd be willing to bet there is some sort of pump control failed, or a bypass valve that is malfunctioning to overload the engine.

Wilson892 · May 12, 2016

Just a thought but there isn't an aspirator box on the intake piping before the filter. Mine was plugged with mud and debris from power washing and then being run before it had time to dry out and bridged over with mud.

For what it's worth, John

KevinArmentrout · May 13, 2016

Hey CD,

Yeah that was actually the second thing we checked. First we took out the filters. Then we rebuilt the turbo cause we noticed some oil leakage. rebuild kit and about 20 minutes she was back together whistlin Dixie!

thanks for the reply!

KevinArmentrout · May 13, 2016

Hey Wilson,

I didn't see one but that is a great thought. I will check today...

Kobelco sk210-lc8 pouring black smoke

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