hey all. we've got a cat 320d that is not working properly. cat mechanic says the prv is not being actuated, so the engine overloads and stalls when operating. for the applications we use it this is a problem as the work it does is heavy work, operator must be careful to not stall it. the official cat mechanic says circuitry is good, we replaced the chassis module after a electrical storm reduced it to crap. all the sensors necessary are reading correctly, the prv has been replaced or rather he tested a new one and the problem persists, everything electrical seems okay (as per his word) the only thing is that the pumps are set differently, when idling, one has 4300kpa and the other around 5600 5700kpa, and that the return line gets rather hot...he mentioned this was next in the list of things to test, but the flowmeter is expensive to rent, like, very expensive around here. so is this problem related to the pumps not being set equally? or some other witchery going on here? thanks
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Cat dealer without a flow meter?
Wouldn't surprise me depending on where in Argentina the OP is located. Anywhere away from the major mining areas or outside metro Buenos Aires it would be unlikely for a dealer branch to have one.
First I would ask what the prv sweep test showed and was The prv calibrated after the ecm swap?
yes they have and as I said to move the flowmeter to my location it costs a kidney (no idea why), if the machine was inoperative I wouldnt think about it that much, but its working for now just needs a delicate hand. serial number is *CAT320DLA6F02361* actually the current ecm was first put into our machine, it had this issue, then because of all this fuckery after checking the wiring, sensors, etc, they went in, put the ecm into a machine which serial number was just one number bigger, programmed it on that machine, brought it back put the ecm into ours and the problem persisted. so the prv sweep test was done on a functional machine
For the few minutes it takes why wouldn’t you do it again. You can do it through the monitor if you have a 600 psi gauge.
One thing I have seen many times on D series excavators is that inside the pump controller there is two spools threaded together, If they come loose then it can cause this issue because the pump will not destroke. The hydraulic tank will need to be drained or pull a vacuum in it to remove the controller without losing all the oil EDIT: Big hex key to screw it back together I think?
whats the procedure for this? i will ask the cat mechanic if he did attempt to do it, im not sure he was able to calibrate the prv on our machine, i think he couldnt do this specific test (thats one of the reasons why they set up the ecm on other machine) and he also tried a brand new prv on our machine but the problem persisted, so thats why i wanted to know what else can it be. is the pump pressure difference, when idling, causing the machine to skip the prv from actually regulating the pump?
Have you checked for active Diagnostic Codes.? See attached. @Mobiltech - it appears as though the only procedure listed to calibrate the PRV on this machine is by using ET. If you have any other information please share.
it asks for a password which I don’t have (the service menu)
Either FFF2 or 9992 should get you in.
Never mind, the machine fixed itself…however the pump pressures are now very similar when idling, 5300kpa and 5600kpa. the cat mechanic guy can’t understand what did the trick, neither do I but well. It’s working now
I’m glad it’s working OK now but I think you are missing a trick if you don’t check for Codes at this point, even though they may no longer be active. If the same problem occurs again at some point at least it may give you an indication of the root cause of the current failure that just miraculously healed itself. What part of Argentina are you based in.? I had a bit of experience down there.
I did check the codes, nothing appears there. btw I am not from Uruguay but I put Argentina cause I didn’t find my country on the list maybe i skipped it
From that it would appear the source of the problem was mechanical. Maybe a piece of debris stuck in a valve somewhere.? A change of all the hydraulic filters and cut the old ones open to look for particles might be a good move because if something is starting to come apart mechanically the evidence should be there. I worked down that way for the dealer in a previous life .........
I will replace the hydraulic filters no doubt, something must have got stuck there
At least you HOPE something may have got stuck in there that may give you a clue as to what is going on. But replacing the filters is only half the job. You need to cut open all the old filters and look inside them for debris. Click this LINK for a video explaining the process. I know it is an engine oil filter but the process is the same for a hdraulic filter. You do not need a fancy filter cutter although it does make the job easier.
this machine had the pump rebuilt and new fluid + filters last year. very shortly after this was done, smoke came out of the ecm, my guess was a big electrical storm screwed the electrical side of things (which was fixed). the sister machine we have has the same issue with the pump not destroking and stalling, but it has 2 override controls behind the right joystick so we use it with that, oddly enough all started after the storm. could be coincidence or not I will definitely open up these old filters and see if theres bronze or any crap inside the hydraulic circuit
I would say that is unlikely unless the machine suffered a direct lightning strike. The usual reasons for ECM issues such as you describe are any combination of: - 1. Welding on the machine without disconnecting the batteries - and the ECM as well if you happen to be me. I prefer to play it safe....... 2. Not placing the welding ground right next to the location of the welding work. 2. Condensation/water entry into the ECM. Any combination of the above will often result in an extra-crispy ECM.
on the spot that this machine was working, high ground on a hill...could have been that, although on that quarry of ours magical stuff happens. so I will probably never know. this storm was also during a weekend and nobody was there.
Points 1 & 2 are well worth reinforcing to your maintenance guys, especially the welder(s).