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Kobelco loss of power

Discussion in 'Excavators' started by Twisted, Jun 23, 2017.

  1. Twisted

    Twisted Senior Member

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    This might get a bit long but I want to include all of the details.
    Kobelco SK200Lc Mark IV. 5.9 Cummins. A couple hundred hours ago the engine started to surge at low idle. If I bumped up the rpm's a couple hundred revs it would be fine. It seemed to be worse when it was cold or when I first started it up. It had good power and no other issues. All new filters and some fuel additive but it still surges at very low idle. New fuel shut-off solenoid about 700 hours ago.
    Now within the last 50 or so hours it has been loosing power while digging. It gets worse after 20 minutes or so and continues downward. It seems worse while using multiple functions but the biggest one I notice is operating the stick but that may be from increased hydraulic load. It got to the point when I had an inexperienced operator on there loading clay, he could kill the engine if not careful so I took it out of service.
    I put on a new lift pump and all new lines. I just pulled the injector pump and brought it to a reputable shop. He didn't find anything wrong yet but he still has to run it on his bench today.
    I don't think it's related but he only other issue I had is 2-3 times in the last few hundred hours is the machine would run out of fuel and almost die. I am 99% sure it was from some blockage in the tank because there was no flow until I blew back into the tank then it would be fine.
    No smoke, clean fuel and air filters. I'm starting to think I'm chasing the wrong issue. Could I be having hydraulic issues that are causing the engine to be overloaded? The cooling capacity on this machine has always been borderline but I notched that up to poor design of the oil and coolant radiators. It's fine if everything is kept very clean. Any debris and temps over 90* and I have to keep an eye on it.

    Thank you for any advice.
    Twisted.
     
  2. Delmer

    Delmer Senior Member

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    Why wouldn't the most simple obvious issue be related to the problem? Put a vacuum/pressure gauge in the cab with a line teed off of the inlet to the injection pump. If that doesn't show anything and the pump guy says it's fine, THEN you have a hydraulic problem.
     
  3. thepumpguysc

    thepumpguysc Senior Member

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    NEW Lift pump & a 2.5bar overflow valve.. & make sure the solenoid is operating at full WFO position..
    IF the new solenoid wasn't adjusted when it was installed, its not opening up ALL THE WAY..
    I pull them completely out of the way to diagnose a low power problem.. ESPECIALLY if the customer said they had "already" replaced it..
    I had 1 "trying" to get to the shop one day.. it was in a HUGE f'n crane that they JUST put a new solenoid on & it had low power..
    I tried & tried to tell the 50yr mechanic that YOU HAVE TO ADJUST IT..!!!!
    We went round & round.. & they finally got a road permit to bring this monster to the shop.. it was THAT BIG.. & they only had "x" amount of time allowed on the road..
    This HUGE DUDE, about 6'6> 375lbs, walks in & yells.. WHERES THIS F'N PUMP GUY?? I got this MF'n crane out here & he says I don't know what the H*** I'm DOIN.. lets see this fu""" fix this..!!!!
    I about crapped my pants.. within 30 minutes I had him ROARING down the road & we've been BEST FRIENDS ever since..
    All I did was take the new solenoid completely out of the system TO PROVE that was the problem.. & when he came back from his 1/2 mile test drive, I adjusted it..
    Long story, not so short>> take the solenoid out & try it.. & please don't walk in my shop yelling profanitys at me.. lol
     
    mikebramel likes this.
  4. thepumpguysc

    thepumpguysc Senior Member

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    The parts list calls for a 1.5 bar ovflo vlv.. pn-101 but if put a 2.5 bar pn-183 [or 184] in the system, it crams abunch more fuel in the engine.. NOT enough to hurt it.. but enough to know the difference..
    I've seen a new 2.5 ovflo vlv fix A BUNCH of running/performance problems.. as a field fix..
    ASK the fuel shop to put it in.. good luck..
     
  5. Bluox

    Bluox Well-Known Member

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    Take the water separator out and take it apart and clean the crap out of it.If its clean you have floaters in your tank.
    Good luck
    Bob
     
  6. Twisted

    Twisted Senior Member

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    Update: Nothing wrong with the injection pump. He tore it all down and replaced any wear parts. It ran perfect on the bench. The fuel screw was turned up a bit but he left it where it was.

    Shut-off solenoid adjustment? If I remember it is a little plunger to stop the fuel. What's the adjustment? He was going to replace it but fresh out. More should be in mon-tue. Should I just pull the guts out and try it? I can manually kill the fuel.

    Overflow valve? I didn't see it but I'll look when I get back out there. The lift pump is different than the one listed in my parts book. None of the plumbing would have worked worked so I used a direct replacement of the one that was in there. I've owned this excavator for over 1500 hours now and it's worked flawlessly until recently.

    I think the fuel stoppage is floaters in the tank but I haven't had time to pull it and flush it out. I get 50-100 hours between this issue happening and it is there and gone like a light switch. The low power is constant and worsening. I was hoping it was a collapsed line or something simple. Everything between the tank and the injector lines has been cleaned and all filters and seperators changed a couple times since this raised it's ugly head.

    I'll put the pump back on tonight or tomorrow and see what happens.

    Thank you for the suggestions. I'll give them a try and report back.
     
  7. Twisted

    Twisted Senior Member

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    If I want to test fuel system pressure, where would be the best place to do so? Just before the injector pump or would there be a reason to put one somewhere else. Excuse the questions as I'm just a simple lever puller.
     
  8. thepumpguysc

    thepumpguysc Senior Member

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    At the filter outlet OR the inj. pump inlet..
    I have a banjo bolt that I drilled out & tapped to put a fitting in, to fit my gauge..
    I just swap 1 for the other, do the test & swap'um back..
    Are we talking about an inline pump or VE pump?? I was assuming it was an inline Bosch pump..
     
  9. Twisted

    Twisted Senior Member

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    Rotary.
     
  10. thepumpguysc

    thepumpguysc Senior Member

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    OH.. cant put that ovflo vlv. in THAT ONE..
     
  11. jujub

    jujub Member

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    My Kobelco 200-6E excavator is not starting. The engine swings but the machine does not start? Any suggestions as to the problem?
     
  12. Twisted

    Twisted Senior Member

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    Fuel shut-off solenoid???
     
  13. jujub

    jujub Member

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    It does not have a shut off solenoid. It has a cable from inside. It is a 2004 model.
     
  14. Delmer

    Delmer Senior Member

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    Can you post a picture of the injection pump? That would save some guessing.

    If it's a japanese engine with an inline injection pump, then the first thing is to check for a screen INSIDE of the banjo bolt in the inlet from the fuel tank on the BOTTOM of the transfer/priming pump. Unscrew the screen from inside the bolt and blow the crud out of it, then put it all back together.
     
  15. jujub

    jujub Member

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    The problem is not with the injection pump because it is a getting fuel but the engine is not starting.
     
  16. jujub

    jujub Member

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    There is no blockage because the engine is receiving fuel.
     
  17. Twisted

    Twisted Senior Member

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    Fuel, air and compression. You are missing one of these.
    Does ir fire at all or nothing?
     
  18. jujub

    jujub Member

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    it fires when starting fluid is used.
     
  19. Delmer

    Delmer Senior Member

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    It would seem the problem IS with the injection pump because it's getting air and compression if it fires with starting fluid.

    So either the injection pump isn't getting fuel, the outlet is blocked, the wires aren't energized, or the pump is bad, or the pump is not being turned. Any other possibilities? Completely blocked injectors?

    Why would they even sell starting fluid in St Lucia? or is that not in the Caribbean?
     
    mikebramel likes this.
  20. jujub

    jujub Member

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    Do you have any information on the pressure at which the injectors fire on this excavator?