Hitachi EX200-2 Problems

[Aaron Prasad]

Hi, my father had bought a Hitachi EX200-2 excavator and from the very start we have had problems with it. The machine has a Manual regulator installed so it’s a manual machine now and all the electrical wires that were present before has been removed before we bought it. The problem with the machine is that at start it operates well but after nearly 10 minutes all the hydraulic operations become slow and powerless. We have installed a brand new main pump(new valve plate, pistons, cylinder blocks and head block), took the control block out and changed all seals and O-rings (over roll), installed a brand new aluminium hydraulic oil cooler, changed the centre joint seal, installed a new charge pump. We have done all this as one by one each mechanic asked so basically the hydraulic system has been made new but the problem still remains and money has just been spent. I’m just tired of this machine and am asking if anyone out there can help me please. All the hydraulic operation becomes slow and powerless after a while and the engine gives off too much smoke. Please help!!!!........

 

[FP-Z71]

Just a shot in the dark, but injector/ injection pump problems?

 

[Aaron Prasad]

So do you think there is a problem with the injectors??....

 

[Aaron Prasad]

The machines hydraulic system at the start is fine , a bit of power but later all actions become slow and power-less but the engine loads from the start...gives of smoke

 

[Eric1975]

I dont know much about hydraulics, but even though it has been converted from electrical to hydraulic control, there must be some type of adjustments on the hydraulic control. Pump angle may not be responding to demand properly. Just my thoughts.

 

[Aaron Prasad]

Do you know how to adjust or where to adjust??....pressure settings??...

 

[shopguy]

I dont know what has been changed to make it non electrical but you need to find out if it is the engine choking or the pump pulling it down,i am confused because pump overstroke will load the engine and cause black smoke from start but the hydraulics will be fast as pump understroke will make the hyds.slow but the engine will run free . Does it do this at the same time or are you having different problems at different times ? There is a member here I think itis sk120 that keeps talking about some manual kit .that may be what you have i would pm him,that is the only time i have ever heared of such a thing till now.I f it was still factory electrical i could be more help.Hope This helps A bit anyway

 

[Aaron Prasad]

Yes, It has a manual kit installed on the top of the pump…some people call it the “manual regulator” or the “manual kit” which changes the machine from an electronic to manual. At the start the hydraulics are good but not too power- full(A little bit fast) but after nearly 10 to 30 minutes of operation the hydraulics slows down and engines makes a sound like it’s giving up and gives black smoke. Thanks for your help….really appreciate your comments….

 

[shopguy]

Does the engine still smoke and pull down with all levers hands off ? like i said we have got to tell if it is pump load or engine for sure/ Does the pump still have the little 4 bolt plates on top and bottom of the stroke piston housing?

 

[Aaron Prasad]

It smokes and pulls down when the levers are applied...as soon as levers are let gone the machines gives smoke but very very lillte....i think the pump is loading the engine...yes i have the four bolt plate on the pump but only at the bottom of the pump...on the top there is a "Manual kit" installed....the four bolted plate at the bottom has a long bolt in the centre of the plate...which can be adjusted.....please what do you think is the problem???..............

 

[shopguy]

Can that bolt be adjusted with the plate installed ?

 

[Aaron Prasad]

yes it can....with a 5/8 spanner to unlock the lock nut and a shifter to adjust the bolt....but i dont know the proper adjustment...should the bolt be adjust by pressure setting...if so how and where should the pressure be tested??....to adjust the bolt??....

 

[shopguy]

That bolt is part of the kit which i know nothing about but I think your trouble is pump control I guess if there is no way to get help from the kit maker I would take it apart and try to see what does what. The stroke piston moves down to stroke & up to destroke I am just guessing but that bolt is a stop or has a spring inside to destroke the pump you can remove the plate and push the piston all way up and lock it there with the bolt,shims or whatever and run it at mim. stroke just to test, it will be very slow but it will dig and this will at the least narrow down the problem.

 

[Aaron Prasad]

Ok thanks for replying. I'd just like to ask about the stroke piston which is called the servo piston, that piston has a ring. Do you think the problem could be the ring??....because i've put on the new pump but haven't changed the servo piston and it's ring

 

[Aaron Prasad]

someone told me that there is a bypass on my pump but my pump is new...i installed a new pump last year....just not the servo piston and the ring....

 

[WhyWhyZed]

I'm not sure how the new pump wouldn't come with the servo piston and ring - those parts are right inside the head of the pump. Did a new pilot pump come on the new pump?
Sounds like you need a guy out there who knows mobile hydraulics. Has anyone looked in the DP system - the relief valves, pilot pressure? Need to diagnose before throwing any more parts at it.
The pilot system is definitely something that can affect the whole machine. What is pilot pressure when the machine is warmed up?

It's going to be tough to try to diagnose this non-stock control system without literature. I have never heard of that before. Is there anything about it on line or is it something some guy fabricated?

 

[WhyWhyZed]

someone told me that there is a bypass on my pump

? nothing I can think of on that pump that would be described with "bypass"

there's a plate on the bottom of the servo you can rotate 180 deg and push the servo to the 70% (I think) displacement position

 

[HATCHEQUIP]

I agree that the pump regulater needs attention but check the turbo for tring to lock up after runnning that 10 minutes......... seen it happen before.. power goes away and engine smokes like a freight train

 

[Aaron Prasad]

Well we just ordered only the 14 pistons, 2 Cylinder heads, 1 valve plate and the Head block. I didn’t realise that I need to change the servo piston and ring also because I didn’t know its function. Yeah I’ve near replace all of the hydraulic system…we ordered the pilot pump separately….just haven’t changed the Manual kit and the servo piston and rings…nah!!...no has looked at the DP system….I’ll have to check the pressure….I’ll let you know soon….thanks for assisting and pitching in though ….I really need help with this machine…it’s just given me headaches!!!....

 

[Aaron Prasad]

oh yes!!....i forgot to mention!!....we placed a new turbo also....my dad thought that the source of too much smoke was the turbo....so we installed a new one....still no change....