Kobelco sk210-lc8 pouring black smoke

[KevinArmentrout]

UPDATE!!

No good news unfortunately. But we did eliminate a couple more things. I hate to say it but I'm really leaning towards hydraulics but still not sure.

Ok. We took the injectors in to have them tested. injectors were tested called for 260bar. 5 of the injectors tested at 230bar and one of them didn't hold for anything. So he said we have one bad injector which was no. 1 cylinder. We cleaned the cylinders really well and reinstalled the injectors. We will have to order one. But there was a little less smoke than before. The cylinders were nasty. I don't think replacing that injector will solve the problem though. Strange the engine is not missing. That thing runs like a champ! I don't know why if that injector is bad....

So after getting everything back together, we dug a scoop of dirt and started going through the functions. Every single function bogged engine down by half. It didn't have enough power to bring the stick in with a full load of dirt. We had to lift up on the boom to get it in. So we shut her down and pulled the lids off the hydro tanks. Inspected the suction filters, etc.. They were fine. Now I'm thinking some type of pressure relief in the main pump maybe? Even spinning the tracks brings engine down. I looked in the manual which was overwhelming on the hydraulic section. Still continue to read, but if anyone has any suggestions, I'm open.
I was reading on another forum about adjusting the PRV (I'm assuming pressure relief??) all the way in to test if it was the relief. I believe the adjustment for mine is one turn out.

BTW, I was asked if it does this in every mode. Yes it does. Also there are no codes displaying.

 

[Delmer]

Strange the engine is not missing. That thing runs like a champ! I don't know why if that injector is bad.....

My understanding is the fuel rail pressure varies with load, so under heavy load the pressure is overloading that injector dumping fuel into that cylinder and possibly causing loss of power from early ignition. Get that injector replaced, and then see what it does.

This isn't a 12 valve cummins, Jethro. You might have to call in a pro, swapping out components gets expensive if you don't know what you're doing.

 

[KevinArmentrout]

My understanding is the fuel rail pressure varies with load, so under heavy load the pressure is overloading that injector dumping fuel into that cylinder and possibly causing loss of power from early ignition. Get that injector replaced, and then see what it does.

This isn't a 12 valve cummins, Jethro. You might have to call in a pro, swapping out components gets expensive if you don't know what you're doing.

LMAO! right you are on that one! Yeah best I could find that injector for was $149
B&D diesel said we could just replace the nozzle for $80

Think I'd rather go with a complete new one.... I'll have to order one today. There aren't too many places that I can find these online. I would think this would be fairly common part. I wish this was a 12 Valve cummins!

 

[CatToy]

I had the same problem on my Link Belt 330, did a lot of the same things you did (even dumped all the hydraulic oil and replaced all filters) but under heavy load still blew black smoke. Finally found a shop that had a IDSS computer that would connect to the Isuzu engine and they found the EGR valve would cycle completely open and stick. I am not an engine mechanic and did not understand the connection to my problem but after they replaced it, no more smoke.

 

[lantraxco]

I had the same problem on my Link Belt 330, did a lot of the same things you did (even dumped all the hydraulic oil and replaced all filters) but under heavy load still blew black smoke. Finally found a shop that had a IDSS computer that would connect to the Isuzu engine and they found the EGR valve would cycle completely open and stick. I am not an engine mechanic and did not understand the connection to my problem but after they replaced it, no more smoke.

I would guess with the EGR stuck open it was dumping exhaust into the intake stream, reducing the amount of oxygen available for combustion... and since it sort of becomes a closed loop, the worse the exhaust gets, the worse the intake gets, etc...

 

[KevinArmentrout]

Hey Lantraxco,

Yeah I read on another forum or possibly a post somewhere on this forum about the EGR. Funny thing on this machine is I can't find one! I'm still looking through the service manual, but I'm glad you brought that up. I had forgotten to check for that in the manual. I figured it would be on the intake??? But didn't see it.

 

[KevinArmentrout]

Hey Shimmy,

Yeah I'm thinking overload too. I am going to replace the injector that tested bad, then I guess going through the hydraulic test procedures. I read in the manual some diagnosing steps with the console screen I can go through. It had no power yesterday, and it basically bogs the motor in half. I am thinking relief valve or something like that as well. I'm just not sure how to test yet..

 

[KevinArmentrout]

Ran through the diagnostics yesterday. The errors that were popping after the test was done was saying pump1 and pump2 proportioning valves need to be adjusted or replaced. It's hard to believe both would go out. Ordering the injector from messicks today. Diesel shop wanted $410 without core and $260 with core. I called Messicks and got the injector for $107!!! Should be here Saturday. Will keep yall posted

 

[lantraxco]

Sometimes the computer shows errors based on faulty information, you may find a sensor is off but not out of range so the computer thinks the PV's are not working correctly.

 

[Former Wrench]

Not being familiar with this machine I will go with the rule of thumb; Black smoke, either too much fuel or too little air.

 

[KevinArmentrout]

just an update. We replaced the faulty injector. Made no difference whatsoever. Last thing to try is the injection pump. I was looking through the manual, but have not found anything about the timing procedures for this machine. When they test this injection pump and/or pull it apart, won't they put it at top dead center. I guess then the question is how do I time both components? Similar to a gas engine? No. 1 piston reaches the top?

the reason I ask this is because the injection pump is just held by the taper of the shaft. There is a keyway or "Woodruff" slot with no key. I'm assuming this timing has to be dead nutz right? If anyone could provide the procedure that would be great! Thanks

 

[John Shipp]

Hello mate,

In the absence of more qualified mechanics, I will say the lack of "key" sounds a little odd.
We once fixed a similar problem where in the final act of stripping the engine in order to remove the pump (to send it for service same as you) we found that the nut holding it to the taper had come loose allowing the gear to slide about. Somehow it had jumped one tooth out of timing, too. So simply lined all marks back up ( was a geared timing set, not chain), tightened it up properly, and gave it a test run- our problem was solved. Lucky fix for us...

So how is your timing gear held in correct place, if no key? Are the keyways still lined up? Can you see all timing marks?

All the best.

 

[KevinArmentrout]

Hi John, Good to hear from ya.

The whole "Jumping" timing thing seems very legit considering the setup of this injection pump. What is odd is the tapered shaft on the pump has a woodruff key slot but didn't have a key when we took the pump off. The only thing that holds the position in place is the tapered shaft and a big nut on the end. The shaft does not move very easy. I would have thought when we were tightening the nut back on the shaft it would have spun since the only thing holding the gear in place was friction. But it didn't move..... while we had it off anyway.... that's also why I wanted the timing procedure for this machine so we can make sure everything is in time; from the pump to the engine. The injection pump would have to be at "TDC" as well as the engine is my thought. Just unsure how to accomplish this on this machine. any thoughts?

 

[John Shipp]

In the absence of any kind of timing marks, sometimes it's the webbing of the block casting or something vague...

Did both the parts that are tapered have a keyway, and was it aligned?

 

[John Shipp]

One thing I was "drilled" into doing by my old dad, was when stripping down the front end of an engine, to line everything up to top dead centre before starting and check out the current timing position and mark it fresh if necessary, before undoing anything. Even to the point of locking or fixing parts in place somehow, on occasion. Then at least you have these points of reference for starting rebuild. If you put a serviced pump back on in the same position, you can then alter the timing if necessary from these marks, but usually it runs fine from these marks. You can put the engine through several revolutions are the start of necessary (before strip down) to understand the timing positions.

There are various ways of finding top dead centre, did you try yet? For marking we use dots of white paint, or centre punch paired dots, or a sharp line filed across some edge where it makes sense.

All the best. John

 

[John Shipp]

For specific instructions on kobelco timing, the only person I have come across who seems to have access to this info is Adam Fairchild, H F Hydraulics. You can google this if you want.
Have your serial number handy if you do contact him!

 

[Martin03]

sk250 hydraulics loading engine

Kevin Armentrout, did you ever figure out what was wrong with your machine? I have a sk250 with the same problem. Thanks in advance.

 

[Vetech63]

My SK 250 had a turbo waste gate that was vacuum operated. It was blowing heavy black smoke when under heavy loads. The waste gate on the turbo was froze up. Just a thought

 

[sstocker31]

Such a shame to read through 3 pages of post / ideas and then not have an answer to what the problem was.....

 

[Martin03]

sk250

I'm pretty sure it is not the waste gate. The turbo was just rebuilt by the guy I got it from and the waste gate actuator apparatus looks new. It was hard to move by hand but the actuator arm did move so the gate is not stuck.