Hoping to get some ideas as to whats causing excavator to stall when i hold boom or stick against relief valve. The stick will cause machine to stall when held against relief wether its all the way in or out. Bucket against relief at full dump or curl is fine, also traveling while operating any circuit is good as well. Seems to only be on the boom and stick. Happens hot or cold. Any ideas on where to start would be appreciated.
Hi Tim, if it is the machine era I am thinking about you should be able to see your pump pressures on the display (monitoring section) There should be 2 pumps displayed, check the pressure at bucket relief and stick relief. In regular mode should be 4785 +- 75psi. Make sure you are only operating 1 function at a time! To be certain of the specs, I will need the serial number and i can look it up. P.S. If the display is in BARS 1 bar =14.7 psi. When operating a single function the pumps should work independently
Serial # 2140 Yes I can see the pressure readings for the front and rear pumps through display and it is in bars. So to check reliefs on bucket and stick would it be for stick completely out? And would bucket be completely dumped or curled? I do have a parts book and service book but some of the material is hard to understand due to my lack of knowledge lol And to check reliefs would machine be at full rpm. Thank you for taking the time to reply
Try to activate your “prolix” switch and see if it makes difference.
Not sure what that means. Are you referring to the boom boost button on joystick?
I don’t know where it is in Doosan, usually it’s on the back of the arm rests or under small covers in arm rests! I know Hyundai has it.
Good day From the best of our information all 225 Doosan models can receive both pumps for boom raise as with arm in, suggest you try arm in see if it has the same effect, most of these machines have a PWM valve which is supposed to prevent engine overload, one check you could make is the output pressure from the PWM when applying both pumps. If the overload reaction is just the boom raise it suggest a pressure sensor or ECU issue, if you need some more information give us. serial number and a picture of the pumps.Could also check to see if there are any error codes showing up. Kind regards Uffex
What does PWM stand for?
Oh sorry PWM Pulse Width Modulation (Proportional pressure valve)it refers to the electrical impulse signals generated from the ECU normally, I suggest that it is much easier to check the output of the valve than try to make anything of the names given to components by boffins, our concern is to fix the machine. The valve you will find at the pump house have a couple of cables connected and the output connects to the pump regulators. Just a point not to overlook are you absolutely sure you do not have a engine power issue at the heart of the problem. We have had many instances where the engine is at fault and the operator is convinced it is a hydraulic - electrical issue. Take care Kind regards Uffex
That’s why I said to try prolix switch which bypasses the whole PRV deal. And I also think there’s problems with pressure sensors.
Attached is a better explanation KR Uffex
The past few days I've been having fuel issue with rust contamination in tank. Where it would stall like ran out of fuel and the longer it ran it seemed to clear up but not completely . Changed spin on filter and runs like it should. 18 deg f , so no outdoor mechanical work today. but when warms up ill pull the screen out of bottom injection put and clean any debris it picked up, also going to try and clean out tank as best i can since its just about empty. There is a fair amount of crud on bottom. I plan on adding some more fuel and pump out with a tube that reaches bottom.
ill check my service manual to see if there is a prolix switch.
Good day Tim Your latest post is far more likely to be the cause of the problem sorry to say the later engines have fuel system that can be very easily damaged by bad fuel, I hope you are lucky it could be a expensive experience. KR Uffex
pulled stored codes this morning, all have different dates as to when recorded code and doesn't give the year, just month and day C:34N:001 Alternator too low - C:21N:002 Dial voltage err(H) - C:23N:002 TPS volt err EPPR current 0 at idle and full rpm Dial voltage idle-3925 mV, full rpm-947 mV TPS voltage/ idle-3945mV, full-1894 Pump pressure in bars. FRONT @Idle 36 - full rpm 44 bars REAR pump @Idle 33 - full rpm 41 bars voltage output- 23.2 volts at idle. 23.6 volts full rpm No real time fail codes does this info help?
If you find your prolix switch then you will know which issue you having, fuel or hydraulic. Another thing is looking for black smoke, but on newer engines it’s not working very well.
EPPRV voltages and pressures supposed to be measured under load ( unless at idle they are WAY off) You need chart for that. I don’t have Doosan manual but here is the link to Hyundai, I don’t think they are much different. http://ce.hhi.co.kr/eng/parts/sm/sm.htm If you can’t open something it means you need to download Asian languages font.
those measurements were not under a load. They were taken a idle thanks
I know, I can read. All I’m telling is to know what’s going on with Power Shift you need to follow the instructions to check correctly.
thanks appreciate the advice!
View attachment 193561 View attachment 193561 View attachment 193561 old timer
This from EPOS. Any idea?
That’s with key on not running. When running only change is red dot next to the zero is flashing along with a green light flashing as well
Hi Tim, sorry about the delay (service call with no internet) I will start out agreeing with uffex that you are likely looking at an engine problem. The EPOS display is '7' is standard power mode, the '0' is digging work mode. The green flash is communication. Your pressures look fine. The dash codes, if they are in history, no worries. If the are current, the 23N code is the TPS (throttle position) open, that is related to the EPPR (proportioning solenoid) not working. Hope this helps
Thanks again for the help. The codes are old from last year. code C:21N is from 1/03/18, C:23N 2/03/18 and C:34N 3/03/18. At that time i needed to change batteries as they went dead. They possibly were the batteries from factory i believe, they had Daewoo markings.Machine was not out working those date staid year. In regards the proportioning solenoid, where would that be located?. And is it a plug and play type of repair to change out. Sounds like it'd be an inexpensive part. Ran machine today without any issues after servicing the fuel system. Currently there's 6010 hrs on it.
Pretty darn good batteries! The proportioning solenoid is on the pump, and it is plug and play. Very glad you solved your problems. Have fun!
On my 225 daewoo when you flip the switch none of the hydraulics work