new here...i have a hitachi ex 120-2 and its a second hand unit,first thing i notice it moves too slow after a few month when i start it,it won't switch in auto mode and the rpm goes high the engine will stop. one of the problem i found is the computer box the resistor is open i try to replace the resistor and its still the same the engine will stop and it move too slow..is there any way to fix my unit without changing the computer box,,and whats the use of the computer box the lower portion?and i try to remove it why still operating and its still same problem..hope someone help me here..
i already replace the computer box and it works but it won't switch in auto and when i try to operate it the engine will stop,i try to remove the computer box the lower portion its still the same when i try to operate the engine will stop..help me plz..
Hey Jigz, where in the philippenes are you from? I can't tell much from your description. If you go to power mode will the engine rev up? When the engine dies is it in a bind like under a heavy load? Black smoke?
hello sir, baguio city but i base in la union,yes if i switch on it won't rev up and if you try to operate it the engine will die,not black smoke,just want to know if i will remove the lower computer box is it possible that the unit will still work?
anyone have a electrical diagram for hitachi EX 120-2?
i replace already the computer box but its the same problem the unit won't rev up and if try to operate the engine will die..
hi im new in this forum, i want help im working with ex 120, here is the problem. when it moves, all movement engine has a black smoke and die. engine is good i think its on the angle sensor, and displacement solenoid, i want help how to chek and fix this sensors, thanks in advance.
hi im new in this forum, i want help, im working an ex120-2. when i moves engine has a black smoke and dies. i think its on the angle sensor and diisplacement solenoid vavle,i want to know how to chek and fix this sensors, pls help, thanks in advance.
your problem is the sensor on the top of hyd pump.to check the sensor using multimeter read the sensor if there is resistance or none if there is no resistance short the wire and start the engine and make a test.and if there is resistance remove the sensor and start the engine and make a test.this is the simply way to check the sensors
reminder before you check the sensors check the computer box first located behind the operator,check the lower portion,check the resistor inside
thanks for the suggestion jigz_2114,, i will try and see if it works.
Hi everyone. I have a EX120-2. When you begin to operate it in the morning or while still "cold", everyting seems to work just fine until after maybe 2 to 3 hours working, when the unit begins to slow down until it can barely move, and you begin to hear some noise in the main pump. We've already overhauled the radiator and oil cooler, replaced the 2 main pump solenoid valves but still the problem persists. After resting the unit for a few hours, it works again as if everything's ok. Any help will be greatly appreciated. Thanks!
I would like to ask, what is the main function of the angle sensor?
proper diagnostic should be done by dr. ex. one cause of your symptom is pilot pump.
the lower portion of the computer box behind the operators seat is the pvc controller (pump and valve controller) the top one is the engine controller unit (ecu) check and see are the red leds flashing on the two controllers if not flashing then that box is not functioning correctly, check this and let us know how it goes
Hi my pump controller keeps burning out the resistor , 10 ohm 5 watt , i have replaced it 2 time after 1 or 2 hr it go again any help on way in dose it , i looked over the harness all looks good
Have one doing same thing you find a answer ?
@Bigdavis41 , Thread is from 2012, may not get a response. EX120-2 pvc resistor issue is discussed in this thread . . .While we are talking about EX120-2, If you need a EX120-2 tech manual , @LACHAU posted a link in the thread below , see (post #9). .