Hitachi Ex120 Problem

[rgl726]

the problem in the pvc is not only on the transistors.

there are other ic needs to be replaced.

 

[Sripola]

Hi guys,

Has anyone here managed to get hold of the shop manual for the EX120-3? I am badly in need of one as the engine on our EX120-3 stalls as soon as the hydrualics get any load. The engine just wont rev up when the hydraulics are loaded (either boom nor travel motors). Much appeciated if anyone can send me a shop manual for this machine to help me troubleshoot the problem.

Cheers

 

[Wardiker]

Hi guys,

Has anyone here managed to get hold of the shop manual for the EX120-3? I am badly in need of one as the engine on our EX120-3 stalls as soon as the hydrualics get any load. The engine just wont rev up when the hydraulics are loaded (either boom nor travel motors). Much appeciated if anyone can send me a shop manual for this machine to help me troubleshoot the problem.

Cheers

Could be a fuel delivery problem, (thats what I had)Check your fuel filters, or just replace, check the banjo filter in the fuel line, and check the line coming from the gas tank, its tends to get clogged. Thats the 1st easiest things to check off.

 

[Sripola]

Hey Wardiker,
We changed all the filters and checked the banjo and gave it a good clean up. Still no luck.
We've got a Hitachi "specialist" coming in and said something about converting the machine to run by bypassing the sensors. See how that goes cuz the sensors on these machines I know have caused lots of people a problem

 

[Wardiker]

Hey Wardiker,
We changed all the filters and checked the banjo and gave it a good clean up. Still no luck.
We've got a Hitachi "specialist" coming in and said something about converting the machine to run by bypassing the sensors. See how that goes cuz the sensors on these machines I know have caused lots of people a problem

Thanks for the heads up, mine was that someone had joined a foot of new line just from the tank to the old, when they heated it up to connect it melted and had a pin hole size to let let the fuel in, we laughed, counted our blessings and she runs great, make sure you post your solution.

 

[Sripola]

Hi Wardiker,
I just noticed on our machine that the machine spews out a puff of black smoke just before the engine dies. Also i noticed that the hydraulic oil tank was getting very hot. I mean i couldnt keep the back of my hand on the side of the tank for more than a couple of seconds it was that hot after just travelling back and forth for about 20min.

But we sold a EX200-3 some months ago and it had a somewhat simmilar issue. The engine was overheating after working for about 20min and just die. Tried everything like you suggested like the filters etc and it turned out it was a bad DP sensor. Got a spare part for about $400 and plugged in in and straight away the machine was working just fine. So its the same fella coming around to repair this one and hopefully can work his magic again!

ANd i will def post the solution if we get it fixed.

Cheers,
imran

 

[Clay35441]

Well guys, I'm back. I finally found someone that could fix the pvc on my ex120. It's still stalling the engine and controls are fast. I went back and read all the posts. I'm going to test the angle sensor and dp sensor this weekend. My pvc is showing a code 22 and 31. Does anyone know what this means? I've also got one other problem, when you mash the (P) or Power button the engine revs up and dies. This has been going on since I've owned it, even before the hydraulic problem. Does anyone know what would cause this, maybe the ec motor.

 

[Wardiker]

Well guys, I'm back. I finally found someone that could fix the pvc on my ex120. It's still stalling the engine and controls are fast. I went back and read all the posts. I'm going to test the angle sensor and dp sensor this weekend. My pvc is showing a code 22 and 31. Does anyone know what this means? I've also got one other problem, when you mash the (P) or Power button the engine revs up and dies. This has been going on since I've owned it, even before the hydraulic problem. Does anyone know what would cause this, maybe the ec motor.

Id start a new thread stating your model, Im sure someone could help, might get burried in this thread though.

 

[rgl726]

Well guys, I'm back. I finally found someone that could fix the pvc on my ex120. It's still stalling the engine and controls are fast. I went back and read all the posts. I'm going to test the angle sensor and dp sensor this weekend. My pvc is showing a code 22 and 31. Does anyone know what this means? I've also got one other problem, when you mash the (P) or Power button the engine revs up and dies. This has been going on since I've owned it, even before the hydraulic problem. Does anyone know what would cause this, maybe the ec motor.

code 22 is abnormal pump control

you should look at the following component:
angle sensor
high speed solenoid
PVC

code 31 is disconnected hyd oil temp sensor or short circuit of the sensor harness

 

[Sripola]

Hi Wardiker,

Happy New Year!
Well we found the problem and also a theory on how it happened.
Well basically the PVC is fried. Overvoltage had blown a whole bank of transistors and a couple of resistors. Also noticed that someone had messed aorund with the angle sensor. So our techie adjusted it "manually" by setting it so that the pump doesnt overheat (i couldnt find the correct calibration instructions for it so had to go with our guy's logic).

The guys took the PVC and repaired it (cost about $200), and we tried a donor PVC and found machine worked perfectly. But put the repaired PVC and machine was ok apart from auto throttle not reponding. So the guy's gonna take a second shot at it and hopefully fixes it this time!

So the theory on how this all happened. We found a pressure sensor for the machine travel was inop. So it looks like someone had tried to adjust the angle sensor to fix this (cuz they didnt know the presssure sensor was inop), and made the prob worse. The next dumb move by this mystery mechanic was prob to have put a voltage through to pin out the harness and thus blowing the PVC. Because when we got to it we could see signs that someone had already been there messing around.

SO hope this info helps. But basically, adjusted the angle sensor, fix/new PVC and a pressure sensor and the machine's a good un!

Also our techie told us that there is a bit of kit to bypass all the sensor and make the machine a "manual" although this makes the machine run slower and not very efficient as you can imagine, so if anyone has info on this procedure i am more than interested as i have heard this procedure from quiet a few guys but its almots an urban legend as no one can give me any technical info on this.

 

[Andre-1]

490E excavator

With the key on and engine not running you should have 24volts to one wire on each of the displacement solenoids, (the ground is controled by the computer and you can not check this easily.) If you don't have 24 volts to each solenoid then you can check the fuses first there is a one amp fuse for each in the fuse box. Make sure they are good then go from there and check the wiring from the fuse box back to the solenoids. Hope this helps.:canada

Hey 3Doc, I have been tryin to log into this forum for very long time now, my password wont reset must be some admin issues, so i created a new account. My previous username was andre01.

Thanks for the suggestions, I got 21.7 volts across each solenoid, i guess thats bcaz the battery was low, with the engine running i get 26volts.

Since my last post i did a lot of things.
1- I replaced the displacement solenoids with new ones.
2- Resealed the swing motor
3- replaced two solenoids on the pilot solenoid valve ( boom and swing function)
4- replaced the DP sensor on the control valve
5- Replaced the PVC

So here is where I am after that. The machine was overheating , was super fast, would easily stall at full extension of any cylinder or under load, and the hammer would stop firing if i move any other function while hammering b4 i replaced the DP sensor,

Now it is not overheating , functions can be operated simultaneously therefore no problem when hammering and will not stall provided that I select tortoise mode and a power greater than Idle.

If I am not wrong, of the two solenoids on the pump, one is for increasing flow and the other for decreasing. I have noticed however that the machine will not overheat and such if the wires are switched around.

When i connect the wires as they should It overheats, but the machine is very strong and as fast as it should be and will not stall provided i select tortoise mode and a power mode greater than idle (eg. L).

Mayb i am wrong plz inform me of which wire ( color code) goes to the solenoid nearest to the door/ front.

My next big prob is that the swing is very weak, all other function are strong except swing, The machine fails trying to sweep an object to the side. Also when on a hill I hav noticed that when swinging the machine it will not come to rest quickly when the lever are in neutral, it swings a good bit b4 comin to a stop.


Angle senor voltage is 4.4volts, i blew air through fuel line back to tank and drain tank which gave improvements in speed. what range voltage should i get on the rpm senosr?

My temp gauge doesnt work.

Any Ideas? Thanks.

 

[rgl726]

Hey 3Doc, I have been tryin to log into this forum for very long time now, my password wont reset must be some admin issues, so i created a new account. My previous username was andre01.

Thanks for the suggestions, I got 21.7 volts across each solenoid, i guess thats bcaz the battery was low, with the engine running i get 26volts.

Since my last post i did a lot of things.
1- I replaced the displacement solenoids with new ones.
2- Resealed the swing motor
3- replaced two solenoids on the pilot solenoid valve ( boom and swing function)
4- replaced the DP sensor on the control valve
5- Replaced the PVC

So here is where I am after that. The machine was overheating , was super fast, would easily stall at full extension of any cylinder or under load, and the hammer would stop firing if i move any other function while hammering b4 i replaced the DP sensor,

Now it is not overheating , functions can be operated simultaneously therefore no problem when hammering and will not stall provided that I select tortoise mode and a power greater than Idle.

If I am not wrong, of the two solenoids on the pump, one is for increasing flow and the other for decreasing. I have noticed however that the machine will not overheat and such if the wires are switched around.

When i connect the wires as they should It overheats, but the machine is very strong and as fast as it should be and will not stall provided i select tortoise mode and a power mode greater than idle (eg. L).

Mayb i am wrong plz inform me of which wire ( color code) goes to the solenoid nearest to the door/ front.

My next big prob is that the swing is very weak, all other function are strong except swing, The machine fails trying to sweep an object to the side. Also when on a hill I hav noticed that when swinging the machine it will not come to rest quickly when the lever are in neutral, it swings a good bit b4 comin to a stop.


Angle senor voltage is 4.4volts, i blew air through fuel line back to tank and drain tank which gave improvements in speed. what range voltage should i get on the rpm senosr?

My temp gauge doesnt work.

Any Ideas? Thanks.

here is the first thing to do with the ovrheating problem.

remove the engine thermostat and observe the machine.

this is located on the engine water return line to the radiator.

pdsv 1 is one near the door. pdsv 2 is near the engine.

 

[Andre-1]

here is the first thing to do with the ovrheating problem.

remove the engine thermostat and observe the machine.

this is located on the engine water return line to the radiator.

pdsv 1 is one near the door. pdsv 2 is near the engine.

It is the hydraulic oil that gets hot, I measured with a heat gun and it showed 180 degrees fahrenheit at the pump, and drops to 120 after the oil cooler. So i suspect this hot pump results in a hot engine since they r connected.

when i reverse the wires connected to the displacement solenoids the machine does not overheat and the oil temp is like 120 fahrenheit and colder after the cooler.

I would like to know which colour wire is supppose to connect to which solenoid in order to ensure that it is connected correclty.

however when connected as i think it shud it is very strong, stronger than b4 and fast, but it overheats. so I suspect the computer ground to one of the solenoid has lost connectivity.

I would like to know how to test the pressure sensor, speed sensor and to test the computer ground to the solenoids.

 

[rgl726]

you need to test is with a 24v L.E.D light. remove the connectors of the pump solenoid and connect the 24v L.E.D light.

do not use any light bulb other than L.E.D. i recommend L.E.D due to lower wattage rating. thats the reason why i specify L.E.D.

move the boom stick up and down. observe the L.E.D if it will light up.

test them one at a time.

 

[johnj]

test

 

[johnj]

Hi all,

Do you know if its a big job to change the ring rear (the wheel that the starter connects too) on a EX120-2 ?

Thanks,

John

 

[cps]

No Not to big of a job John, you maybe able to leave the pump in place, just drop it back a bit to get at the fly wheel!
Also you might what to replace the rear crankshaft seal when your in there!

Aiden

 

[danushka]

I have sent you an email with the page from the manual to set the voltage. Let me know how it works.

if you have ex200 lc manual pl send (danushkab@gmail.com)
i have same problem spunkeymonkey machine have
my machine have wire huness short
PVC control card resistant damage

 

[danushka]

what is resistant oms and voltage nears diode number
what is the day you send email to me
this 3 part are damage

 

[johnj]

Thanks Aiden,

Did you ever get your shop set up ?