PC200LC-6 Bogging Down

Tyler Mannino · Oct 5, 2022

Komatsu PC200LC-6
C10940
2001
21300
102

My machine has started acting up this week , the first 10 minutes or so of the morning the machine will run fine functioning properly but when it gets heated up it is as if the engine is bogging down, it has black smoke pouring out of the exhaust while digging and dumping out the bucket, if you arm out and hold it the machine will kill itself and then crank right back up. I replaced the turbo today thinking the black smoke was a lack of boost/air and the turbo on it was caked in oil on the intake side. No change, about two years ago H&E replaced what the mechanic said was a proportional valve underneath the hydraulic pump. The numbers written on it are 010774. I unplugged on of the wires on this valve and it got significantly worse could barely lift up the boom. Could it be going out again? It was replaced about 1.5 years ago, thing was 700$, any way to test it ? https://www.youtube.com/shorts/-UuJVi_-81E (Short video of machine running)

Thanks for any advise.

Tim Modine · Oct 6, 2022

You need the service manual and a good technician with a flow meter to ck the pump or pumps. I had a similar problem where my pumps weren't de stroking causing an engine overload situation, you have to make sure theres no fuel issues also, (youve already eliminated turbo factor), and after an extensive search for the right person by asking questions and spending countless hrs on the ph awaiting call backs. I got lucky and found the right service guy. I replaced the EPPR valve on my excavator because thats what my dealer said after their so called testing. No change, the tech that came out (from another state $$$, Dependable Hydraulics in Connecticut) after about 3.5 hrs found my pilot press way to high and made some adjustments to the front and rear pump regulators. He also pulled out my EPPR valve and found that the 2 poppets/ ck valves were installed incorrectly causing my pilot pressure to be to high and corrected it. It works like new, smooth, no stalling when dead heading cylinders especially boom and stick functions, travels straight . My advice is to find someone that knows Hyd.pumps with a flow meter and service manual for your serial # . I've got a Kawasaki pump which the tech that came out rebuilds them, so he was very familiar with it. There's a member on here Old Timer who's a genius from Canada (Ehh) who diagnosed my problem early in my post and was spot on maybe he'll chime in.
Good luck

Tyler Mannino · Oct 6, 2022

I’m pretty positive it’s not fuel related, injection pump was off in the past year and it was fine, multiple sets of new fuel filters , lift pump was replaced when pump came off. I’ll track down a manual I guess

Tim Modine said:
You need the service manual and a good technician with a flow meter to ck the pump or pumps. I had a similar problem where my pumps weren't de stroking causing an engine overload situation, you have to make sure theres no fuel issues also, (youve already eliminated turbo factor), and after an extensive search for the right person by asking questions and spending countless hrs on the ph awaiting call backs. I got lucky and found the right service guy. I replaced the EPPR valve on my excavator because thats what my dealer said after their so called testing. No change, the tech that came out (from another state $$$, Dependable Hydraulics in Connecticut) after about 3.5 hrs found my pilot press way to high and made some adjustments to the front and rear pump regulators. He also pulled out my EPPR valve and found that the 2 poppets/ ck valves were installed incorrectly causing my pilot pressure to be to high and corrected it. It works like new, smooth, no stalling when dead heading cylinders especially boom and stick functions, travels straight . My advice is to find someone that knows Hyd.pumps with a flow meter and service manual for your serial # . I've got a Kawasaki pump which the tech that came out rebuilds them, so he was very familiar with it. There's a member on here Old Timer who's a genius from Canada (Ehh) who diagnosed my problem early in my post and was spot on maybe he'll chime in.
Good luck

Tim Modine · Oct 6, 2022

Tyler Mannino said:
I’m pretty positive it’s not fuel related, injection pump was off in the past year and it was fine, multiple sets of new fuel filters , lift pump was replaced when pump came off. I’ll track down a manual I guess

Its the only way to eliminate pump issues. Can't do it without the service manual and flow meter. I watched the video does it still smoke like that after changing the turbo? Air filters Good? Gotta run thru the list, i exhausted every possibility even down to the banjo screen and changing every single rubber fuel hose lol. Drove me nuts

Tyler Mannino · Oct 6, 2022

Yes, it runs slightly better I want to believe but that may just be me being hopeful I didn’t waste 700$ lol. The old turbo was caked internally in oil so I guess it’s fine I replaced kit anyways.

Tim Modine said:
Its the only way to eliminate pump issues. Can't do it without the service manual and flow meter. I watched the video does it still smoke like that after changing the turbo?

fastline · Oct 6, 2022

Black smoke is almost always a lack of air. You need to comb the entire intake for possible issues. Swap filters, etc. Aside that, determine if your turbo is variable geometry. If so, that seems the likely suspect. I believe most of these are modulated with oil pressure so that needs looked at. This is not hydraulics related.

Tyler Mannino · Oct 6, 2022

I replaced the turbo tho. Took main air filter out and only have the inner on it same thing. Only leave the pipe from the intake and the small blue hose between the turbo and the metal intake on the top of the engine

fastline said:
Black smoke is almost always a lack of air. You need to comb the entire intake for possible issues. Swap filters, etc. Aside that, determine if your turbo is variable geometry. If so, that seems the likely suspect. I believe most of these are modulated with oil pressure so that needs looked at. This is not hydraulics related.

fastline · Oct 6, 2022

Tyler Mannino said:
I replaced the turbo tho. Took main air filter out and only have the inner on it same thing. Only leave the pipe from the intake and the small blue hose between the turbo and the metal intake on the top of the engine

Read what I said. Do you know what a variable geometry turbo is? If not, learn about them, then your machine.

Tyler Mannino · Oct 6, 2022

fastline said:
Read what I said. Do you know what a variable geometry turbo is? If not, learn about them, then your machine.

Only what i could read on the internet. Is that determined by if it has a waste gate or electric actuator

fastline · Oct 6, 2022

Tyler Mannino said:
Only what i could read on the internet. Is that determined by if it has a waste gate or electric actuator

It should be be pretty simple to figure out if you have a VG turbo. Look at your books, online specs, etc. I can't answer the question. There is a Komatsu pro around here that would know, but you can probably just look up your part number for the turbo and learn about that.

John C. · Oct 7, 2022

Have you checked for fault codes on the monitor panel. Do you know how to get into that part of the menu?

Does the engine in this machine have multiple valve covers or a single long one? Does that 21,300 number you provided represent the hours on the machine?

Tyler Mannino · Oct 7, 2022

Has multiple covers for each set of valves. No the machine has 10,800~or so hours My cab does not have a monitor in it just two gauges for heat and fuel manual throttle

John C. said:
Have you checked for fault codes on the monitor panel. Do you know how to get into that part of the menu?

Does the engine in this machine have multiple valve covers or a single long one? Does that 21,300 number you provided represent the hours on the machine?

John C. · Oct 7, 2022

Those hydraulic pumps don't usually last more than 6,000 to 8,000 hours. It's time to repair or replace the hydraulic pump. Is your machine factory or has someone pulled all the electronics out of the cab?

Tyler Mannino · Oct 7, 2022

John C. said:
Those hydraulic pumps don't usually last more than 6,000 to 8,000 hours. It's time to repair or replace the hydraulic pump. Is your machine factory or has someone pulled all the electronics out of the cab?

Factory grey market machine. I could test the pump with gauges I guess ?

Tyler Mannino · Oct 7, 2022

I’d find it hard to believe it’s the pump tho? It will dig and lift itself up , you can spin the machine withthe boom and All.

John C. said:
Those hydraulic pumps don't usually last more than 6,000 to 8,000 hours. It's time to repair or replace the hydraulic pump. Is your machine factory or has someone pulled all the electronics out of the cab?

Tim Modine · Oct 7, 2022

I believe in systematically eliminating possibilities starting with the easy stuff filters hoses etc. Its a process and you'll get there. Get the engine ruled out first then move to hydraulics. If its still smoking after the new turbo it could most likely be an engine issue. Start there, I'm no mechanic, diagnosing is labor intensive. Stick with it. I went thru my entire machine and it wound up needing the regulators on the hyd pump adjusted, mine didn't smoke like that when i dead headed the cylinders though. The hyd pump tested fine for flow before the repair to eliminate pump replacement other than my pilot pump press being to high which was from 2 ck valves on a new eppr valve i had installed by someone else who swore he put them in right. Took me about a year to get it fixed. I called all over the country trying to get answers. No local shops wanted to take the time to diagnose. Either they didn't have the knowledge to do or wanted the liability if they touched it.

Tim Modine · Oct 7, 2022

Do you have to feather the controls while digging to keep it from stalling?

Tyler Mannino · Oct 7, 2022

Tim Modine said:
Do you have to feather the controls while digging to keep it from stalling?

I’ll make a longer video of it running. It’s got a 48” bucket on it I can dig and heap the bucket(smokes the entire time) and when you’re bringing it closer to you and booming out the cut itll wnt to die so you let off and the rpm’s come back up

Tim Modine · Oct 7, 2022

sounds identical to the way mine was running. it would bogg down bad especially on rear hot days mainly when i used the stick and boom functions. As those two circuits on my excavator use both the front and rear hydraulic pump. Mine didn't smoke like yours did, but if i didn't feather the controls it would stall. I've got 8300 hrs on it and i change my hydraulic fluid and filters every spring no matter the hrs since the last change. Is your fuel cap vented? Hydraulic tank vent? a few other things to check just to eliminate.

Tim Modine · Oct 7, 2022

Like i said I'm no mechanic but i did replace a lot of parts on it fuel wise, including the filter head assembly. I eliminated every little item air, fuel, turbo and turned out to be hydraulic after being told by service.techs it was the engine.

PC200LC-6 Bogging Down

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Senior Member

Well-Known Member

Senior Member

Well-Known Member

Senior Member

Senior Member

Well-Known Member

Senior Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member

Well-Known Member