Got an ex-100 (-2) I believe. Ran fine till ec motor stopped working which I thought was the issue so I put a new one in. Once’s installed the buttons still didn’t make the ec motor move. Had someone familiar with electrical check it out and was told the pvc computer was bad. Discontinued part apparently so got one from china. Installed today and didn’t seem to change anything. Maybe ecu computer? Not sure but hate to keep throwing parts at it. Only way to run or shut it off is to manually pull the cable. Sometimes it runs fine then randomly it will try stalling if you pull the lever. After a random amount of time you’ll hear the motor raise idle very little bit as if pressure was relieved and work fine until it repeats the cycle. It is random and has a mind of its own so cant seem to pin point what is causing it. Any help would be greatly appreciated. If this has been post before I apologize. Thank you
Welcome to HEF Mike ! You need @LACHAU for this one. He is the Hitachi Guru. If that machine has any wires shorted to ground for any of the sensors, the PVC (Pump and Valve Controller) will shut down and operation becomes difficult. With those machines, the first thing I recommend checking are the fuses. Make sure none are blown, and make sure the correct amperage is in them. I can't recall which fuse it is, but there is a 1 amp fuse for the controller. If anything higher is put in, then the PVC can get fried. Also, plugging and unplugging the EC motor with the key on can also damage a PVC. Also, if looking at the PVC, does the light on the cover blink about once a second?
This model of machine has been in production for a long time but it is difficult to repair because it controls the hydraulic system electronically. To fix it, you must have knowledge of both hydraulics and electronics. According to what you have described, it is possible that it is stuck in the hydraulic part, but it is also possible that a few electrical connectors are loose, so it flickers like that. It's really hard!!! Now, try to carefully check the electrical connector from the PVC box to the 02 solenoid valves installed in the main pump. In the PVC box, there is an LED light, you see how that light works. If it blinks regularly, it's working fine.
All fuses look to be good. Haven’t tested amperage. Led light is about a flash per second on both ecu and pvc. Where is the solenoid located? There a way to test if the solenoid is junk or have to buy new?
Also want to add that I,L,E,P don’t do anything as well as they used to. After seeing your picture attached I thought it would be the ec computer but the red light flashed regularly about once every second
Are both solenoids the same? Can I swap them to see if it reacts the same way? Thanks
The function of 02 solenoid valves: One to reduce pump flow (reduce engine load), and the other to increase pump flow (faster action). If only one of the two is damaged, the machine cannot work. You refer to the picture named electronic regulator construction above for more clarity
Ok so I found them is there a way to test them? To see if they are the cause of my issues? Thanks
Also want to add yesterday I had it running on high idle with the throttle manually pulled back as I,l,e,p still doesnt work and once standing outside it sounded as if someone was trying to pull one of the levers to operate the machine. The safety bar to activate hydraulics was disengaged so machine didn’t move. Could this possibly be a sign of solenoid sticking or damaged? or something different. Apologize if I have stupid questions haha I’m new to the excavator world mainly repaired skid steers but nothing major like this issue.
You can also check the fault codes by doing like the picture below.
@LACHAU so I finally had some time and replaced both solenoids with no luck. But I did notice if I wiggle the wires going to the angle sensor (I believe) the machine sounds like it’s trying to go under load. Any chance theres a next step I should take? • Both computers flash a red light at about 1 sec on 1 sec off so I assume computers are both good. • 2 new high speed solenoids • EC motor was replaced but will not operate, I have to manual pull throttle to run the machine • And to refresh memory machine runs how it wants, can dig for 10 mins or even up to an hour then suddenly will try to stall out if you try to move the hydraulics.
Update! So finally figured out the stalling problem. Plug for angle sensor was shorting as it was a very loose fit. Put new plug and so far couldn’t get machine to act up!! Only issue I’m having now is I,L,E,P still will not do anything. Can move ec motor by hand so it isn’t binding. What could cause this issue? Thanks! @LACHAU