I just got this circa 1994 EX-100, original owner thought the pump was going weak but I don't believe it is that. The hydraulics were slow, but recently it kicked into rabbit mode so now everything is fast. Now it randomly moves from slow to fast back and forth. He removed the electronic cable off of the engine and put mechanical pull cable to control the throttle. The buttons on the side don't work for the idle speed settings. Non of the fuel tank/temp gauges etc work. The buttons for the travel speed and lower section of the panel change when you push them but they don't actually change the machines settings. The red light is flashing on the PVC like normal, but no light on the EC. I unplug both the EC and the PVC and the machine still starts, runs acts like it does with them plugged in. The same buttons on the side panel do the same things even when these are unplugged. The key doesn't turn the machine off, only the mechanical fuel lever. Right hand lever works nice and can do micro movements easily, the left lever as soon as I start the machine gets really stiff, and lets full pressure through with very little movement. Boom out and in as well as turning left while pushing the lever fully will result in the movement continuing even when the lever is returned to neutral. You have to move it back in the same direction again to stop the movement or reset it with the lever on the floor to the left. I'm thinking the EC board might be fried but I took the top cover off and didn't see anything obvious. Manual doesn't show me which relays do what so I don't know how to even check if the board is getting power. I'd like to remove the mechanical throttle and put it back to factory. Any input or advice on what to check/test is appreciated I'm lost on what to check right now. Thanks
I'm also getting codes 20, 26, 31
Here’s a link to the technical manual for your machine. https://www.mediafire.com/file/d6lbevr1c8dk6ao/EX100-2_Technical_Manual.pdf/file It sounds like you have an electrical issue between your pump valve controller (computer) and your hydraulic sensors and solenoid valves when you say it randomly switches between low and high speed. The codes you listed will be in that manual somewhere and should give you a good starting point. One thing though is that if this is the original wiring harness in the machine you will likely be in for a lot of gremlins as these harnesses were made of some not so good quality materials. On my EX200-2 of the same era the only thing that fixed all the gremlins was to completely rewire the entire machine. Luckily you can get complete harnesses and they are not the biggest deal in the world to change, I have a whole thread somewhere here about that exact operation, HeavyEquipmentForums also you can watch a video I made of it here: https://youtu.be/uMawv3aOnS Hope this helps a bit.
Oh wow that manual is huge, I only had the first 200 pages before. Thanks I appreciate it. I'm going to call a local Hitachi dealer tomorrow to see if I can get some part numbers for the EC and maybe a harness. The PVC seems to be operating okay, I am getting no response from the EC
You’re most welcome! On mine the EC is dead too, but with the manual throttle the machine works just fine… I would recommend getting a good harness first then worry about the EC later…