I am in desperate need of some help on my machine. I have a hitachi ex120-2. that the throttle is not working. on. i am getting 15 volts and sometimes 25 volts to the 2 power legs of the ec motor. when i hook the ec motor up the throttle will jump from power to off and keep repeating. we have replaced the control pad, the ecu, the cab harness,also a new ec motor. if anybody has had any problems like this or has any ideas please help. thank you
Bad ground? Has the machine ever been used with a rotted-out muffler? Sometimes you can save a lot of money be bringing in a good, emphasis on good, mechanic. You need an older guy with Hitachi/Deere specific diagnostic tools (DR EX) and experience with the machine. Hope somebody gives you a better answer, but those machines have bad gremlins.
the exhaust has always been good. we have done resistance tests on the outside of cab harness. the resistance came back good on all of the wires. and i can not find anybody to touch it because its a grey market machine. im just pretty much lost on what else to test. the harness, control pad, and were all bad in the cab. when i replaced them it allowed me to have power at the ec motor. but still does not function properly
Many times when the ec motor keeps stroking like that it is a shorted harness. Most of the time I've found them damaged where it runs under the hyd pump. Poked by sticks or just oil soaked and the insulation comes off.