Excavator was running well but suddenly the engine has started abruptly shutting down when operator tries to raise the boom. Any help would be appreciated.
Checked control valve, spool. No debris or blockage wad there. Relief valve is also found to be working alright. Rest of the functions are working.
EC240, B , C , D . and S/N The dipper arm in or out in relief was ok
Good day Any recent line connection been changed? Kind regards Uffex
MCV was overhauled but problem started after a couple hours of slugging operation. Now engine starts collapsing when boom is raised and/or track is steered.
Ec 240 LC.
Does the engine pull down using the boom function in both directions?
Only when raising the boom or steering the tracks. Straight travel is ok
My first thoughts are that the negative control line are cross connected, if the boom fails to stall when you operate in combination with the arm will confirm if this is the case. Kind regards Uffex
Hey Mike what do you think ?
Good day I am not familiar with MCV being overhauled what exactly has been done ? KR Uffex
Please describe, "shutting down " Sudden and abrupt stall, turning off as if keyed off or stalling from excessive load. MCV overhaul, were pressures reestablished after overhaul? If boom is stalling you out. Suspect port and main relief may be bottomed out. Without seeing its behavior, I'd start there. So straight EC240 would be more Samsung than Volvo. Cummins power with stepper motor. Are you reaching full throttle at no load.
Stalling from excessive load while boom is raised. At no load machine is reaching full throttle. MCV was dismantled and all O-rings were replaced without disrupting pressure setting of any valve. Main relief valve has been replaced a month back .
Engine is stalling when operated in combination also
It doesn't matter that the setting itself wasn't disturbed, it's that the valve as a whole was disturbed. I would start by verifying pressure settings, if we can't establish that, everything else is a guess. If you need specs I can look them up for you. Another suggestion would be to track the control lines back to source. Left side pump negative control should go back to bottom left of MCV right side to right. Again, checking pressures would verify this quick enough. The wrong pump will stroke up if incorrect . The MCV will try to compensate through the center passage but it can't do everything.
Please see pressure chart. And compare against description for Boom raise function. Please pay special attention to the center passage description where P2 is diverted from tank to combine with P1 to work against boom up pistons.
Good day I would endorse FwF suggestion I would add connect a gauge to the negative side of the cylinder raise the boom and check the back pressure should not exceed 1 or 2 bars - is there a chance the spools have been switched as this is a very unusual occurrence ? KR Uffex
Hydraulic pump regulator fork lever found broken. Suspecting problem there. This same lever has often broken recently. Will update as i know more.
That is uncommon. I don't think I have ever found a broken regulator. Leaking and sticking from foreign debris but never broken. And you say this has been a repeat failure. That's gonna be a challenge to find cause.
That is true if that has happened before it indicates a fundamental issue with adjustment as FwF suggests finding the cause would be the logical way to go. Kind regards Uffex