Hitachi EX 100-3 jerky hydraulics

First post, my topic dont seem to be discussed...

EX100 -3 1995, 9000h
the hydraulics in the levers seem to pulsate, and the whole machine starts to jump, somtimes you can fel that the levers looses pressure if you are using all functions, turning arm and boom and when pressur comes back (it just falls out for a super short millisecond) as you understand it will be a war between what will hget the oil and its starts to be wery unsmooth. just relese the handles and start over.

The pressure to the pilotcircut is about 45bar
the main pressure is 300bar if i remeber correct. +-.

changed out the acumulator for the pilot circut (it was dead) to a new with 25 bar gas, it seems to be 5% worse with a working accumulator. that is just a feeling, hard to say.
been serching youtube, and it looks like all 100-3 is a little bit unsmooth in the hydraulics, but i dont know...
More rpm, wors it gets.

Does anybody hawe any clue where to search? is the 25bar accumulator to low pressure? it shall be about 0,75 x pilotpressure generally in that kind of setup of other machines...

Excuse me for my missspelling, do not speak english normally, lives in the same country where thay say that Santa lives (Finland).

/Jonny

Flow test your pilot pump. When the get worn out they'll still pump pressure but the flow drops off.

Yep. Thats a thing that i have thought about. But i cant really find what nubmbers it should be anywhere on anything... does someone have what i should get when testing stuff? Pressure and flow...

Welcome to Hef Jonny!

Is this something that just started? Any main pilot system hoses been replaced lately?

bought the machine for about 1 year, its been "bad" ever since. did not really noticed when i purchased it... you need to have some load on to the machine.
nothing is replaced.
acually i tried to find a flowmeter yesterday, but where i can get on of those is for me unclear still.

But as i mentioned in my first post, when i been watching on the tube, they all seem to be a little bit harch in the movements, and as time flies you know how to hold tha handles and when to calm down so it dosnt start to jump like a compactor on the ground... i dont really know what to look for, #lost

With those machines things can get complicated real quickly. Diagnostic software is a must for those units.

Maybe post a video of the jerkiness?? You need @LACHAU to chime in.

Kind of hard with the phone between the knees...
https://youtube.com/shorts/dEIQNTHoBJA?feature=share

Dr.zx ordered and waiting.

Yesterday i realized that the A-sensor is broken, new ordered (3weeks), it was 5v no matter how i tunrned the sensor. also no ohm diffrence between any cables.
Both solenoids on the pump has about the same ohm (16 isch ohm).
What i dont understand is that the machine works pretty good, its "slow" not that slow that everybody elses is when they have problems, and it works but it dont have anough flow in the pipings. it has power. and the flow seems to be following the rpm, so my thoughts are: has the previous owner swaped the axle to the swash plate and then just left it there?
Does any body know what angle/pressure/behaiviour it becomes when its turned 180deg? i mean the plate with 4 screwes with the pin to the swashplate?

The hydraulick doesnt load up that much, it loads up. since i dont know how a properly working machine is to be its hard to know how a machine from 1995 should be.

volt on meter, bland to black, red to red. key on. engine off.

Jonny Lehtinen said:

volt on meter, bland to black, red to red. key on. engine off.

Click to expand...

There are 3 wires to that sensor. One will have 5 volts all the time, one is the return (ground), and the third wire is the wire that should change when you turn the sensor.

mg2361 said:

There are 3 wires to that sensor. One will have 5 volts all the time, one is the return (ground), and the third wire is the wire that should change when you turn the sensor.

Click to expand...

Yep, the other (not ground) did not read anything.

Good day
If your drain or return connection has become obstructed (Blocked filter) it can result in this type of issue.
Kind regards
Uffex

It was the same before and after filter change. nothing in any filter.

Does anybody have a repairmanual that they are willing to share? i have one repair manual, but it doesnt really cover much motre than how to take the engine apart.
I would really apriciate that, hitachi ex 100-3, jonkolehtinen@hotmail.com

Hello, I have a few manuals and have the same problem with my 120-3 although it's on a conversion kit, I will send you what I have.

Does someon have dr.zx that works (win 10), got it on mail here the other day, but the cd was faulty, or say, the program did not work.

got new a-sensor yesterday, assembled it and adjusted to 4.4v, machine did run pretty nice for a while( it was raining and the fan in the cab is crap) after about 30min it felt harsh in movment again.
this morning i tried to see what settings the a sensor had, 0.0v. ?!? yes it was a ebay sensor.

have read the ebay sensor is crap, but, it worked a while... and i got steady 5v in, so can it really be bad? erth thru the harness (a sensor harness) and + is 5v, it means that both are present!?
but the signal cable is 0.0v

the altenator is replaced a while ago (not me), what should i have ate the batteries when running at idle? 27.6v?
if higher, could that be a issue? searching all posibilities now...

It should be around 27.5V at idle. If you are hitting 29.5V or higher at any rpm that would be cause for concern. Some of our newer machine's don't set a code until 33V. In my opinion, that is way too high. Also check for AC voltage at the alternator output (at fast idle and all loads on). If it exceeds 0.5V AC then you would have a bad diode. Stray AC voltage and electronics don't play nice together.

messured the voltage at the batteries today, got 29.5v at idle.

both the boxes heart beat is 1/sec, all sensors are ok except A-sensor who broke again (ebay).
the a sensor gets steady 5v all time. why did the ebay sensor break? crap quality or?

Jonny Lehtinen said:

messured the voltage at the batteries today, got 29.5v at idle

Click to expand...

So long as it does not go over 30 I can live with that. Did you check AC voltage? How are the batteries?

Jonny Lehtinen said:

both the boxes heart beat is 1/sec

Click to expand...

That means they are working as they should.

Jonny Lehtinen said:

why did the ebay sensor break?

Click to expand...

eBay says it all.