Hello Gents. I recently purchased a 96 Hitachi Ex200 excavator and since i bought it the hydraulics have had a surging issue. It is much worse when its cold but happens even when its warm. When i track the machine it is bad enough that it bounces me in the seat. You don't notice it as much digging but swinging and tracking you can tell something is off. One test i did to make sure it wasnt the drive motors was put the boom down to the side, lift one track up off the ground, and run it full speed. It ran fine for about 15 seconds and then slowed down to a crawl. As soon as i hit any function with the joystick the speed of the track would resume to normal and start all over again. This happened with both tracks. It has great digging and tracking power just isnt very smooth. Any suggestions for troubleshooting?
The Hitachi guys will probably need to know the dash number (EX200-2 ,-3 or EX200LC-5)?
It’s a 1996 Ex200LC -2
I would start by servicing the hydraulic system. Drain oil, remove suction screen and clean or replace. Change out your return filter and put in a clean bucket. Replace your case drain and pilot filters. Then service the breather filter, make sure the vent valve functions properly. With the hydro filter, carefully cut it apart. Lay all the pleated material out with the outside up. You're looking for bits of vinyl or metal. Get yourself a filter cutter. No, a muffler cutter or grinder will not do. Cut the head off the case drain and again carefully cut the pleated material and lay it out outside up. Now you're looking for anything, mostly brass. Pour out what oil is left in the bottom of the filters canister. Do you have any sparkle in the oil? My hope for you is that it's as simple as a sticking vent valve . Does it make any unusual noise when it surges?
Follow Funwithfuel's advice first. If that does not resolve your issue you may want to investigate the following. I believe the -2 machines have the electronic hydraulic pump with angle sensors and displacement control solenoids. Hydraulic instability could be caused by something as simple as the little spring on the angle sensor shafts. Those springs like to break causing play between the angle sensor and the pump swashplate. If in fact you have those pumps and elect to check that out make sure you mark the angle sensor so you can put it back into the exact location. The adjustment on those is very sensitive.
So i serviced the system today and changed the pilot filter, return filter (in tank) and the filter screen (also in tank and looks to be the suction filter for the pump). What i didn't see anywhere was a casing drain filter. Is the vent valve the one in the top of the tank with the button to relieve the pressure your speaking of? Any special way of testing if its working correctly? Good news is i took the filters to the John Deere place and had them cut them open and inspect them since i didn't have a proper filter cutter. The service tech said they looked great and no abnormal signs of wear or damage in any of the filters. Also no noticeable sparkles in the remaining oil. It seems to only surge on the swing function and the track function (both tracks evenly). When slewing i can see the pilot lines to the swing motor jumping around in tune with the surge. The drawings don't show that the pilot lines for the slew and track functions being separate from the digging functions but i guess instead of moving a cylinder it is driving a hydraulic motor so it would be more sensitive to pressure fluctuations.
Tomorrow i plan to remove the sensor and have a look. Is there any other testing i can do to the A sensor or the two solenoids on the top of the pump to check their operation? Also just in case i dont get the sensor back in the correct spot. Is there a calibration procedure?
Off your pumps, travel motors and swing motor should be some -8 or -10 lines running to a common spin on filter. That would be your case drain. We had a member last month who had all kinds of problems caused by a bad plunger inside the case drain filter housing. If you search floridamechanic, you'll find his thread, its lengthy, but has some vague similarities.
Hitachi/Deere Excavators do not have case drain filters. It is a sealed reservoir and so long as the reservoir holds some pressure you should be in good shape. If in doubt replace the cap. You can swap solenoids from on pump to the other to see if things change. Same with the angle sensors. The best way to adjust them is with MPDr program and watch the cc/rev of the angle sensors. If you don't have any Hitachi software the you can use a digital volt meter. Angle sensors can be adjusted to 4.45 V when measured at the sense wire (backprobed in the center terminal #2) with the pump at max stroke. Unplug both pump solenoids or unplug the dp sensor allow the pumps to go to max displacement. Unplugging the dp sensor, pumps should go to max right away. Unplugging the pump solenoids it can take up to 5 min for the pump to go to max. When at max measure the voltage at the backprobed #2 terminal on the angle sensors. Hitachi spec is 4.40. Set angle sensor to 4.45 DC Volts max. If set higher than 4.45 V the PVC will destroke the pumps too soon.
Thanks for clarifying MG2361. I thought all Mfrs used case drain filters. Much appreciate the correction.
Thanks for the help mg2361. I will head over later today and complete these checks. Two final questions before I start. When I swap the two solenoid valves on top should I unbolt them off the pump and move them (how much oil will I lose?) or just move the solenoid itself? Also I only noticed 1 angle sensor on the forward side of the pump is there another on the other side? Thanks again!
Thanks for the ideas anyway
Since I have been with Deere since the middle 80's I have zippo experience on other excavators so I did not know other manufacturers used case drain filters. Following your posts as well as other posts in this forum has taught me quite a lot. At least not having case drain filters takes some of the guess work out. Travel motor grenades, sends shrapnel to the reservoir, then it goes through the suction screen back to the pump which promptly distributes the debris throughout the system. No Brainer. One super size clean up coming up. You want fries with that? The solenoids with their housings. Yes only one angle sensor. Item #12 in the attached is what you want to check.
You know, silly question, how tight are your tracks. Tight chains will cause travel issues. Won't do squat for your slew, but will definitely screw with travel. That should shoulda been job 1, check track slack. I'm sorry I forgot that.
Do I have to drain the oil to pull the solenoids or will I not lose much?
To be honest I didn’t look to hard at it. I followed your directions above and when I unplugged the DP sensor and both the solenoids I was reading .777 volts DC at the center wire (white wire) 5.02 volts on the red wire which I assume is the power for the sensor. When I plugged everything back in I read 1.22 volts DC. ??? I’m confused ♂️. Other than that measurement how do I know my pump is going to full stroke? It didn’t seem to make much of a change in the sound of it. Bad sensor or exteamly out of adjustment ?
This afternoon I started the machine up cold and with cold oil (33~F). The hydraulic surging happens on all functions when it’s cold, and seems to clear up in the digging functions once warmed up to operating temp.
As far as I remember your machine should have HPV 091. Do not swap solenoids on your pump, it is not one solenoid per one pump as on K3V on some Deer models! Both solenoids run both pumps simultaneously. Your pumps totally controlled by those two solenoids, there’s no other hydraulic/mechanical controls, first you need to try to retrieve the trouble codes, codes may give directions. If not - start checking and testing components such as: N sensor ( RPM), Fluid temperature sensor, A sensor, both control solenoids, etc. Very often on these systems problems caused by something giving off believable but wrong signals.
If I buy a Dr.ex or Dr.zx online can these read the codes or should I just call the Deere place and get a service tech out?
You can do flash codes in -2. You gonna need scan tool to read values if it comes to that.
If you can put a vacuum on the tank that would be great. If not, then release the pressure on the reservoir and place a pan under the pumps. Oil will come out of the solenoid ports but the holes will be small. Usually when there is a solenoid failure you will either have full hydraulics stalling your machine or no hydraulics, depending on which solenoid fails. Did you check the third wire (sensor ground). Should be 0.100 V or less. TVA made a good point that I should have mentioned. Definitely check if there are any codes. Attached are instructions for acquiring codes without the diagnostic software. Also I attached a list of codes from a JD 490E which is the same vintage as yours with the same hydraulic setup. So the codes should be the same.....I hope
Thanks MG. I did check the third wire (sensor Ground) and as you said it was right at .100 V. I read through the instructions you send for the fault finding codes (THANK YOU) and i see they mention performing Retry A procedure and Retry B procedure. What is this? Do you have these procedures available as well? I am heading out again tomorrow to do some more troubleshooting.
Unfortunately you need the diagnostic program to perform the retry procedures. I attached procedures anyway.
I pulled the codes this morning 4, 18, 22, 23, 24, 25, 26, 28, 29, 30, 35, 40...... holy hell thats a lot of codes. What would cause that amount of codes to be thrown? I tested the A-sensor again and with all sensors plugged in it was reading .908Vdc. I unplugged all the sensors and waiting ten minutes for the pump to go to full swash and it was still at .908Vdc.? I never heard a tone change in the pump though to prove the pump went to full swash. I also tested between the black and signal wire on the A-sensor and got .808Vdc. With that many codes where should I even begin? Changing the A sensor?
This many many codes usually means wiring problems, or bad ECU. I would clear the codes and start over again to see which ones are hard codes which old and not active. Another thing is grounds and feeds.Both chassis and ECU, have to be checked under load.
And the only way to clear the codes is with a diagnostic tool?
Unfortunately yes. You could try disconnecting the battery but I don't think that will do it. Worth a try.
There’s should be instructions how that clear the codes by jumping contacts of DLC. But I don’t remember exactly how it’s done, and I’m out of the office for couple of weeks.
Try to short contacts 2and 4 within after one second after turning the key on.
The same connector that i inserted the G wire in from the instructions posted by MG above? Diagnostics Computer Connector?
Diagnostic connector
Thanks. Il give it a shot.
I tried disconnecting the batteries for a few hours but it didn't seem to clear any. Thanks again MG
Alrighty guys. So i broke down and called the Deere tech out to take a look for me. He was there about 6 hours troubleshooting with his diagnostic tools and found that one of the solenoid valves on the pump was malfunctioning. He replaced both of them for good measure and set the Angle Sensor for me. He also went through all the pressure reliefs and set them to the correct spec. While he was there i had him install two more relief valves in the aux circuit so i could install my thumb. It was an expensive trip to have him there but well worth it in the end. Thanks for all the help guys.
Glad to hear it. Thanks for the update.