hitachi ex120-2 engine stalling and dieing!

[Rohan Fernando]

hi, everybody
i got a problem with my hitachi ex120-2. the engine stalls and stops when a lever is pulled to its maximum. but this does not happen when the levers pull little (for slow movements). i have tested the angle sensor and found it is o.k. also tested both the high speed solenoids on the top of the pump and both gives the same ohms and not grounded as well.
when tested with the machine running , one of these solenoids shows 14 vdc while the other show nothing,(the one closer to the engine). measured with a digital mm.
can anybody help me to sort out my prblem? i do appreciate if i can have electrical wiring diagrams of this machine. my mail address "basicdevices@sltnet.lk" .

thnx

 

[AndrewC]

Did it just start happen or has it been getting worse for a while? I would start by checking your fuel system for clogged filters, low fuel pressure etc. Isuzu engines usually have inline screens in some of the fittings. Check that first. I don't know much about the older Hitachi control system for the hydraulics but I have had a lot of fuel contamination causing similar issues.

 

[wilko]

When you release the lever does the engine recover quickly or slowly?

 

[Orlando]

Did it just start happen or has it been getting worse for a while? I would start by checking your fuel system for clogged filters, low fuel pressure etc. Isuzu engines usually have inline screens in some of the fittings. Check that first. I don't know much about the older Hitachi control system for the hydraulics but I have had a lot of fuel contamination causing similar issues.

Exactly what Andrew says here, I was having trouble with the same thing on my machine it turned out to be both dirty filters, replaced both and now its fine.

 

[Rohan Fernando]

When you release the lever does the engine recover quickly or slowly?

yes Wilko, the engine recover quickly as if nothing happen!
the engine can be raise (accelerate ) and even under high rpm at the engine the engine stops abruptly when the levers pulled to it's maximum.
but remember that all the functions can be performed in slow without any problem.

thanx

 

[Rohan Fernando]

Did it just start happen or has it been getting worse for a while? I would start by checking your fuel system for clogged filters, low fuel pressure etc. Isuzu engines usually have inline screens in some of the fittings. Check that first. I don't know much about the older Hitachi control system for the hydraulics but I have had a lot of fuel contamination causing similar issues.

for AndrewC, no , I have no idea about it. but could it be the fuel supply since the engine can be raised to its maximum with a costant high rpm?

thanx

 

[JDfan500C]

Yes it could be the fuel. Sounds like you need to service it, if it works fine under easy load but struggles when you really work it sounds like not getting enough fuel when its needed.

 

[wilko]

If the rpm's bounce back as soon as you release the control it's not likely to be fuel related. A fuel starved engine will take several seconds or more to recover. For your sake I wish it was a fuel problem.

 

[rgl726]

2 possible problem:

angle sensor and high speed solenoid

 

[Rohan Fernando]

2 possible problem:

angle sensor and high speed solenoid

thanx rgl726,
will work on it.

 

[Ronald Lanoue]

Can somebody help me on my EX120-2. It stall when you bring the bucket in or out all the way at low or full idle. I have replace 4 sensors wiring harness and still the same issue. I have just bought this machine and spent 10K. Now I don't know what to do next.

 

[cuttin edge]

Can somebody help me on my EX120-2. It stall when you bring the bucket in or out all the way at low or full idle. I have replace 4 sensors wiring harness and still the same issue. I have just bought this machine and spent 10K. Now I don't know what to do next.

You should start a new thread. This one is pretty old, an the right person might not see it.

 

[thepumpguysc]

Depending on what fuel system is on it.. they have filters inside the banjo bolts connecting the fuel supply line to the lift pump.. just unscrew & remove/unscrew the plastic or brass filter, clean out & reinstall.. couldn't hurt to see..

 

[Rohan Fernando]

thanks everybody!
for all of your generous replyies.
i am back on the sddle once again!
rohan

 

[Simon C]

So what was your final diagnosis Rohan on your machine.Thanks on behalf of everyone else reading.
Simon C

 

[Rohan Fernando]

So what was your final diagnosis Rohan on your machine.Thanks on behalf of everyone else reading.
Simon C

yes Sir,
it was a fuel filter related matter. replaced the fuel filter, cleaned the entire fuel line up to the fuel pump
and found lot of dirt. the filter had been clogged unbelievably!
you know why, in our country every body used to re-fuel the machines at work sites with the help of 20 or 30 liter canisters, and in the go they do not care over the cleanliness of them and spontaneously adding lot of dirt to fuel, because mostly they buy from a nearby retail vendors, not from fuel stations.

the matter contributed directly as it was starving he lounder tad due to blockage.
or else as i said it raises with no load.

once again, i would rather give an advice to all of my colleagues in this forum as , firstly look all the aspect of operational mistakes by the user before dig into further!

 

[Rohan Fernando]

sorry for the typographical mistake, it should have been,
"it was starving under the load due to blockage"

thanks

 

[skyking1]

have you cleaned out the tank sump, Rohan?

 

[Rohan Fernando]

Dear Skyking1,

Yes Sir, i did it altogether! and had to flushed several times.

what i found from the sump tank together with pretty much dirt, sludge and some sort of a gummy
substances was surprising.
heaps and heaps of bristled shopping bags, would you believe me?
well, i found how the stuff got there.
many workers used to put a folded shopping bag on to the mouth of the 20 or 30 liter can, and then
close the cap to minimize the spillage from the mouth while in transport. however nobody of them
worrying the pieces of bags or as a whole falling into the tank at pouring on to the machine's tank.
and in this machine the strainer at the filling mouth was missing, may have been so long,

Rohan

From Sri Lanka,with Love!

 

[Diesel Dave]

Yes Sir, i did it altogether! and had to flushed several times.
what i found from the sump tank was surprising ,heaps and heaps of bristled shopping bags, would you believe me?
well, i found how the stuff got there.
many workers used to put a folded shopping bag on to the mouth of the 20 or 30 liter can, and then
close the cap to minimize the spillage from the mouth while in transport. however nobody of them
worrying the pieces of bags or as a whole falling into the tank at pouring on to the machine's tank.
and in this machine the strainer at the filling mouth was missing, may have been so long,

Rohan

Complete lack of care , Ridiculous !
The new fill mouth strainer will help the situation