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Hitachi Ex120 Problem

Discussion in 'Excavators' started by spunkeymonkey, Jul 7, 2009.

  1. timmy

    timmy New Member

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    timmy

    did you get the schematics as i need it to
     
  2. timmy

    timmy New Member

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    timmy

    you can go to the john deer bookstore www.johndeeretechinfo.com look up 490e it is the same hitachi make john deer
     
  3. MR. KOBELCO

    MR. KOBELCO Resigned

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    PARTS & SERVICE MGR. AMOUNG OTHER HATS @ KOBELCO D
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    with john deeres or hitachi there are two sensors - pressure differential sensors located on the main hyd c/v.
    if the hyd sensors malfunction then the hyd pump control will not work right.
    this could be your problem.
    i would suggest you do cycle times on each track.
    lift track in the air and mark one shoe with paint.
    line up paint mark
    run track and time total of 3 revolutions.
    do the same for the oposite track.
    you may see a diff between each pump.
    swap sensors on main c/v and retake cycle times see if they swap as well.
    does the machine track straight?
    also what hyd pump do you have?
    kawasaki mfg# ?
    normally many hyd pump repair shops are not setup to rebuild/reseal hyd pump regulators for they do not have a test bench that can verify calibration of the pump.
    flows/pressures.
    likely the regulators were not touched.
     
  4. Hitachi120

    Hitachi120 New Member

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    Hitachi 120-3

    I have a machine that has low power to the tracks, and low power on the swing. There is a bank of solenoids that are unplugged, but if they get plugged in the tracks and swing stop completely. Is the computer in limp mode? I ohm tested the solenoids(7 total), all but one were @ 24.Ohms, the one for the right track motor was 68 Ohms. not sure what the spec is on them. Center joint seals are all new, I tried swapping the solinoids on top of the main pump, but no change. They both tested the same for ohms. ?? -3DOC can you help with how to check the voltage of the angle sensor, and what it should be? Any help would be appriciated.
     
  5. fijijoe

    fijijoe New Member

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    Bula guys, new kid, been following this thread with interest. Original problem was with engine loading. a "repairman" had a look and said the problem was in the control unit.got that serviced but not only original problem but now the left joystick controls the left track. oh boy!!He got the piping wrong. ex100-3. help!!!
     
  6. willie59

    willie59 Super Moderator

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    Welcome to the forum fijijoe. :usa

    I think the best thing you could do is get the repaiman back out there and have him get the piping sorted out. :)
     
  7. sultan

    sultan Senior Member

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    I have a few questions that need to be answered before I can help you.
    1. What do you exactly mean by "engine loading"?
    2. By control unit, do you mean the computer or the valve block?
    3. Does the left track pedal now control the stick?

    He probably switched around a few pilot lines.
     
  8. fijijoe

    fijijoe New Member

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    Bula Sultan,to answer your questions
    1.the engine stalls if any lever is activated,i.e tracks or swing/stick. if it is nursed slowly, it picks up, but if it is used normally the engine labors or stalls.
    2.valve block
    3. yes, the bucket cylinder
    i am sure that he switched the pilot lines. i got this machine 2nd hand w/out any manuals, am not familiar with piping yet.
     
  9. fijijoe

    fijijoe New Member

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    Thanks ATCOEQUIP,i've been trying to get him back for over a month to sort out the pilot lines. no such luck yet.
     
  10. PBR

    PBR New Member

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    Florida
    I also have an ex 120-2 I have a melted Yellow wire with red tracer. It goes to the top front Solenoid valve on the left side of the valve bank, From the fuse panel. I ran a new wire and when I plug it back in to the solenoid it blows the # 9 Fuse (solenoid fuse) How do I check to see if the Solenoid is bad or if it is the angle sensor ? Thanks
     
  11. PBR

    PBR New Member

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    By the way my machine is doing the same thing , At the end of the stroke motor tries to die also on the swing it tries to die and machine chatters . You can tell that the pump is loading up Thanlks again
     
  12. diggerj

    diggerj New Member

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    ireland
    Hi all, new to this forum. instresting !!
     
  13. diggerj

    diggerj New Member

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    Could i get one too -3doc ?
     
  14. YELLOMTLMILITIA

    YELLOMTLMILITIA Well-Known Member

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    Are these turboed engines?
     
  15. PBR

    PBR New Member

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    yes
     
    bluetick likes this.
  16. YELLOMTLMILITIA

    YELLOMTLMILITIA Well-Known Member

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    I hate to sound like captain obvious but has anyone checked to make sure the turbos havent went down on them?? if the air filter is clean, and the air inlet screen is clean and thier still overheating and blowing black smoke. sounds like my old hitachi 200 when the turbo crapped out.
     
  17. rgl726

    rgl726 Well-Known Member

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    hi -3Doc,

    i also have this same problem on my ex 120-2, i was able to remove the pvc unit on my other and it works for 5 days and then there is new problem.

    now its the stick problem. when you give little movement on the stick it loads the engine. when you give extreme on stick its also to fast.

    it seems he can only sense extreme signal.

    what is this problem?? help please also if you can send me electrical schematics or service manual is very helpful. thank you

    my email is rgl726@hotmail.com
     
  18. -3Doc

    -3Doc Well-Known Member

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    British Columbia
    This seems to be a problem for a lot of people out there!! I am a little overwhelmed by all the questions about pump controls.
    I will try to explain how the system works and the most common problems that can cause the -2 blues as I call them!

    There are 4 sensors that monitor the system and tell the computer what is happening so it can control the pumps.
    #! N sensor, this is the small sensor on the top of the hyd pump that monitors the RPM of the engine.
    #2 P sensor , is the sensor on the outlet port of the pump that monitors the pressure that the pumps put out.
    #3 A sensor, the small can shaped sensor on the side of the hyd pump, this monitors the angle of the swash plate inside the hyd pump to tell the computer how much oil the pump is tying to put out.
    #4 DP sensor , is the can shaped sensor on the top and in the middle of the control valve. This tells the computer the difference in pressure between what the pump is putting out and what the valve bank is using.
    If the wiring to any of these sensors is bad or the sensors are bad or the fuses are bad all of your pump control is lost and many of the above problems can occur.

    Shall I continue with diagnosing where to start!!!?:eek::eek:
     
  19. -3Doc

    -3Doc Well-Known Member

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    I have found that most hyd. problems on these machines are electrical problems! If the computer can not see what the pump is doing it will basically shut down and the pumps will slowly go to full swash and put out way too much oil and everything will speed up and loose power and the engine will be overwhelmed and smoke black smoke and stall.
    The biggest problem is crispy wiring in the pump aria that has broken or shorted out, this is the best place to start looking. also check the fuses and make sure they are all good and also the right ones in the right places. this is very important so you don't fry your computer!!
     

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  20. fijijoe

    fijijoe New Member

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    hi guys, anyone got any schematics for pilot piping to control valve block for a hitachi ex100-3. would be obliged for any help.