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  1. N

    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    With that filter not being in the system like it was the fluid didn’t get to be filtered and I believe that was what was causing the fluid to be so aerated. We thought the fluid just looked like it had some water in it but when you look at sight glass with a flash light shining across it you can...
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    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    Ok we’ve been back on the machine today and correctly adjusted the angle sensor. Machine still has a slow intermittent hydraulic issue. We have not had the machine long and we have been trying to figure out this running issue before did the standard maintenance stuff like new fluid and filters...
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    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    I appreciate that, I’ll be able to get back on the machine in a few days I will adjust that correctly and report back
  4. N

    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    I definitely did not do that adjustment correctly.
  5. N

    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    Can you give me the page number for that. I have the technical manual and the workshop manual
  6. N

    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    When adjusting the angle sensor you look for 4.4v with key on and engine off right?
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    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    I will check that but I believe we are able to get max pump flow. The reason why I think that is before we replaced the pressure switch the engine sounded like it was constantly under load when sitting still using no functions and when you would use a function it would bog the engine extremely...
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    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    Can the machine operate correctly (meaning electrically for the variable pump displacement) if the machine no longer has the electronic throttle controls? Our machine has a manual throttle that was installed by previous owner and the step motor and throttle angle sensor are gone but all other...
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    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    Definitely wasn’t aware of a procedure like that so it’s possible but what does that procedure do to the functionality of the pump? Seems like the machine is working properly most of the time but intermittent slow functions but can get them back if you mess with multiple functions...
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    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    No sir, the best I got was 2v with the original and the new angle sensor. I really don’t understand the system good enough to know what would be the effect of have an angle sensor that was only set to 2v? Would that tell the pump to pump more or less or does is tell the EC to tell some other...
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    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    I do not know if the pilot lines were pulsing before today I didn’t grab the lines while it was running until after we unplugged solenoid
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    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    After running the machine with that solenoid unplugged for 20 minutes or so the hydraulics for the tracks would get slow but you could get them back if you messed with the boom functions and vice versa. If you grab the pilot lines where the pilot filter is located back by the main pump, it’s...
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    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    the bucket curl was so slow. Prob 10-15 seconds to only use half the range of the cylinder. So we unplugged the solenoid valve and and started machine and it’s curling normal speed now. It’s the solenoid that works the bucket curl for the pilot circuit I’m pretty sure. That block area has spots...
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    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    Had some time to mess with machine again today. Replaced the pressure sensor and everything seems to be working well except the curl on the bucket. We removed the solenoid/valve made sure is didn’t look clogged and reinstalled. Manual says it should ohm out between 5 ane 23.2 ohm. Our solenoid...
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    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    Yes middle wire is only .04v
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    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    Key on engine off we have .04 volts on p sensor middle wire
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    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    Should it be low voltage with key on engine off or is it just good if it’s under 4.75?
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    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    Thanks for the info diesel Dave I’ll get one coming from Friday parts
  19. N

    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    I checked that I have more than 4.75 volts but that’s just reference voltage right? Couldn’t I have reference voltage and still get a false output reading if the sensor is bad internally? Sorry for so many questions just trying to fully understand what and how it works. Is rhe pressure sensor...
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    Hitachi ex120-2 intermittent slow hydraulics for all functions.

    I looked up that part number and it sends me to one that Friday parts sells. I’ve looked at that sensor and in the application section it doesn’t specifically list an ex120-2. Does anybody know if that is still the correct part for my machine??
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