My 320l 9kk model was working excellent the last few years. However last week I went to do some digging and under load the engine stalls . I changed the filters and no difference . I then checked the turbo as there was some black smoke as it stalled , turbo didn't spin as freely as i would like so i installed a new one . same problem , to me it feels like the pilot controls are telling the hydraulic pump to go full pressure and then stalls the engine . Is this problem common with excavators. really don't know where to turn and desperate . Cheaper to sell machine then to get dealer service call. I don't have a hydraulic service manual , I know the main pump pressure is 4980 psi and pilot system is 600psi . The pump control unit is showing normal green light so that must be ok . the main pump must be being stroked too much and hence stalls the engine . Any ideas ?
It sounds to me like the PRV solinoid has failed or become disconnected. Or as another guy on here recently found a wire to the engine speed sensor was broken. Look your wireing connections over carefully, especially any place repairs have been done or you have powerwashed. The the speed sensor tells the computer how fast the engine is turning, when you work the machine the computer looks for a Target RPM and sends a signal to the PRV solinoid which adjusts the Powershift pressure to the pumps. The Powershift pressure plus System Pressure destroke the pump to keep the engine at Target RPM. Later Bob
Where would the PRV solinoid be ? PRV stands for ?? There are no sols or wires on my main pump , however there is a hydraulic block with several sols and hyd. lines going to it and two or three lines going to the main pump.
PRV Proportional Reducing Valve and it's on that block you mention. One of the small lines going from the block to the pump is Powershift pressure and serves both pumps equally. There should be two more lines coming from each end of the main valve and going to the pump feeding that half of the valve. These lines are the NFC lines Negative Flow Control and tell their respective pump when a circuit is activated and flow is needed. Later Bob
Jeeze Thank -you Bob wish I knew as much as you do about this system . So do my 320 have two pumps in that housing. There is a high pressure line on top and one on the bottom of the pump housing and those two go to my control valve body. What kind of voltages would be on those sols on the block( manifold). and when should those be opening and closing ? I don't have a service manual so I'm just flying in the fog . really appreciate your time and info .
The power is low and variable, controled by the computer to provide the needed PS pressure to control pump flow and keep engine RPM on target(around full load) reguardless of system pressure. The solinoids are calibrated by adjusting PS pressure at two points. Need instructions to make computer sweep the pressure and then set the two adjustment points. What's your serial#? Later Bob
A quick way to test the PRV is to use the monitor and do a sweep test. Stall the pumps one at a time and listen to the engine. You will hear a nice smooth fluctuation in rpm as it sweeps.
The prefix is 9KK, don't have the # right at hand . I wish I had some pics so I would know what valve is what and what each sol does .
Start with the basics, The fuel system is the first to check but you did that. Did you clean the screen on the transfer pump? The speed sensor is also something to check. Remove it and clean it. Install it by screwing in by hand until it touches the flywheel then back it off 1/2-3/4 turn. The screen is in the banjo bolt where the fuel enters the pump. Here is where the speed sensor is located. It is good practice to clean them every so often because they catch the metal that wears off the starter and ring gear.
Thanks for the pics Lee, So if the speed sensor was dirty as you say , would that cause the engine to be pulled down on its knees ? The engine runs fine in all positions on throttle range selector . I don't think its a lack of engine power , but its really hard to decipher. If the little screen in the lift pump was plugged, would the engine still give off black smoke as it begins to stall . I can keep the engine from stalling by quickly releasing the load on the joy sticks or letting the sticks go to neutral I will check that tommorrow and inspect that little screen in the lift pump
If the fuel screen was clogged you would likely starve for fuel and not have black smoke. More likely have an ECM issue like bad signal from speed sensor or PRV signal out of calibration. Later Bob
Thanks again Bob for the reply, going to check speed sensor tommorrow and will check fuel screen for the hell of it .
ah, I forgot about the black smoke. I assume your air filters are clean enough?
Ser# is 9KK 01222. I pulled off the inlet at the turbo just to make sure . i removed the speed sensor and cleaned it . it was full of what looked like gray grease. screwed it back in until it touched the crank and then backed off about 1/2 turn . still the same . the engine will die if i don't let off on the sticks. still haven't checked the littel screen in the lift pump . its a bitch to get at and it was only 0* this morning and windy at 7:00 AM . hands were frozen .
Cat man, Take a look at this thread: cat 312 BL hyd problem. You will have to search for it because I'm not smart enough to link you to it. Although it's for a different machine, it contains instructions from Jerimiah Sr on how to adjust the PRV solenoid to isolate it as the potential problem. I was having the same problem with my 312, and it was the PRV solenoid ($100 part from Cat). This adjustment is quick and easy, but be cautious as I have no idea how much the systems changed from the 312 to the 320. Good luck.
This one: HeavyEquipmentForums
Well It looks like I may have found the problem . The is a mode switch in the joy stick housing just under where your left elbow would be . i slid off the cover and the switch was in limp mode or the "turtle position" I switched it to auto and tried the digger and it seems to work as normal . how the switch got to limp mode , i have no idea. I have never had the cover off since I bought it but there were signs that somebody switched it as there was dust disturbed on the name plate. My machine is locked everytime i leave it with power disconnect off and side panel locked also . Somebody must have gotten into it (Cat keys are everywhere) and switched it. Thats the only scenario I can come up with . It was working fine one day and not the next. somebody had to know where the switch was plus the result of switching the switch. No a very nice trick to play, cost me a new turbo plus unnecessary filter change, plus four or five days work. there's no way the switch could change on it own. i'm not happy with the situation but glad I can get back to work to make a living . My only question now " is "auto" the correct position for the toggle switch?
Yes, the limp home mode is a manual mode to limp the machine to safety. Low power not meant for working. Later Bob
Yes Bob, so would that be why the machine would be stalling in that mode . Now I wonder if the switch is hooked up the right way. I tried the digger in auto mode this morning and it seems to run great.
WELL IT LOOKS LIKE MY PROBLEM IS NOT FIXED . THE MACHINE WORKS OK IN THE AUTO MODE BUT IS SLOW , WHEN I GO TO THE LIMP MODE (TURTLE ) the machine speeds up but will stall when i induce a load . So I'm wondering if the wires on the switch is crossed. I wish i knew what sol was the PRV one . I would change it. So back to sq. one.
If you want to find it, put machine in auto and get it working right. Then go back and unplug one solinoid at a time. The one you unplug and the engine dies under load is the PRV sol. One more thing are you running in power mode 3? Later Bob
Thanks again for replying Bob , so I put the machine in Auto (thats the slow mode right now and it doesn't stall) I unplug each sol at a time ....Will that damage anything ? So when and if the engine dies in Auto I have found the PRV. If that happens wouldn't I be having a problem in both modes as its not stalling in the auto mode right now but is slow and not as strong as it should be . Just wondering if the wires are switched . Thanks for the help Bob , I have to send you up a bottle of Newfie Screech LOL .
It will not hurt anything. The slow mode is the solinoid unloading the pump and not stalling the engine, that's why it's working slow. Now if you look at the dash/moniter do you see Power Mode's 1,2&3. They will adjust what comes out of the PRV Solinoid and thus slow down or speed up your machine. I think it will give you 60% power in 1, 80% power in 2 and 100% in 3. There are also work modes too that effect speed. Dig mode is fastest, trenching mode dedicates one pump to the swing to hold a trench wall straight and fine grading isolates the pumps, no two pump flow for stick or boom up and lower speeds for fine control. These controls might be your problem. If you get this figured out by flipping a few switches just sit back and roll yourself a good smoke. Later Bob
Bob , I'm learning more every time you post . I thought that the three modes only increased engine rpm and had nothing to do with the pump output. What your saying is that the three different modes control power output of the pump too? A friend of mine was telling me that there are two sliding valves in the side of the main pump. he said to remove the four hex bolts on the side of the pump and remove the sliding valve and clean it with some 600 grit sand paper. he said some kind of stuff accumulates on the valve and keeps it from sliding back and forth . he said there are two valves there on the pump , one valve controls travel and swing and the other controls booms and bucket (forgot which is which though) is there any truth to what he told me ?
Don't know about your digger but I had that problem on my EL300B Cat with those valves jamming, ended up replacing them because they were badly worn and that was causing them to jam.
This morning I started checking the sols. I had the machine in auto mode and it was slow ,put in limp mode and went fast but would stall . tried all the different power modes and digging modes ....very little difference. So back to auto mode and the first sol. I disconnected the made machine act fast but i could stall it as if it were the limp mode . I guess thats the PRV solinoid . Now what, I guessing that the PRV sol is working. I'm thinking now about those sliding valves in the pump. But would like someone elses opinion that has some experience in this area . Thanks to all the fine people who are trying to help me.
FOUND THE PROBLEM!!!!!!!!!!!!!!!!!!!!!!!!!!! The morning that I encountered the problem I dropped a bottle of water down behind seat on my left side . The is a porcelean resistor (something like the ign resistor used to be on older Dodges/Plymouths) just below where the limp mode switch is located . I must have knocked one of the spade nose connectors off. Installed the wire and now the digger seems to work as good as it ever did. Sooooooo relieved !!!!!!!!!!!!! Thanks to you guys for all the info, I hope I can help you or some other person that has a problem.
I've been watching this thread and picked up a lot of info that is new to me and applies to my 320L. Thanks to all who posted.
Norite . what kind of trouble are you having ?
Glad it wasn't my bottle of screech that fell in there and broke, been a big fire. Sounds that wire was carrying the signal to the PRV to control your pumps. Was going to print you some pages but the modual contained 198 pages. Will get you the media # might be cheaper to buy one. If you have it you can use the moniter to do the calibrations if needed. Later Bob
Bought a used 320L a few months ago. No work for it at the moment, just cleaning it up to get it ready for next summer. The motor just idles, doesn't speed up when I turn up the throttle control. I didn't know about the limp mode switch until I saw this thread. Going to try that next time I fire it up. Until I saw this thread I was going to troubleshoot the problem and if it was a defective computer I was thinking I would just put a manual throttle cable on it but this gives me hope that this is the problem/solution. Will let you know how I make out. Thanks for your interest.
Norite , don;t touch the limp mode switch behind your left elbow. the auto and manual throttle control system is under the cover on your "RIGHT side" . There should be two toggle switches there .One switch is spring loaded to neutral , by flicking it one way or the other will increase or decrease engine rpm . The other switch is just auto /manual modes. auto I believe. lets you set the rpm from your dash while manual mode lets you set the rpm from the adjacant toggle . You may have a fuse blown to the electric speed control. Maybe its a dissconnected wire or the speed controller could be gone . Get a helper to rotate the button in the dash . you don't need the engine running, just the key on . you should be able to hear the speed controller running when its suppose to change rpm . I believe its a small metal box just above your fuse panel and pump controller . You can trace the two throttle cable back from the injection pump to be sure .
Should be a couple of pressure switches in on the main valve, they control the auto decell, the throttle control that keeps engine speed low untill you move a lever. connect the wires together and see if it reves up. Later Bob
I'll try your advice Bob and let you know, thx. Started her up yesterday, started and idled good, but still wouldn't rev up. Found that limp mode switch as was described here, it really is well hidden, don't know that I ever would have found it without your help and w/o a manual, going to have to get one of those. Anyway the switch was in the turtle positon, so I reset that. Didn't make any difference to my issue, but needed to know about this anyway. At least now the numbers 1-10 appear on the dash (display pnl) as I turn the speed knob up and down, I don't remember it doing that before. I attached a picture in case someone else is looking for this switch. You have to slide that cover to the rear and the switch is in there under that cover with no label on top of the cover, took the pic after I moved the switch.
Hey guys, I've been watching and 'listening' to this website for quite some time and always been able to find what i need except for this time. I've got a 320l that has no power. It seams that the pumps arent swashing (but are even when flowed out 6gpm standby @4,000 psi or so). This also happened all at once and cant seem to find the problem yet..
Hi sheep , my 320 used to stall everytime I went to do a movement , I thought it was fuel , did all the easy stuff first . there is a very small filter screen down on the lift pump and it blocks off from time to time . I think its in the banjo fitting bolt . I'm sure BoB who knows these machines inside out can help u there. I found a wire off a resister behind the seat down on the left side just below the switch that is shown in the above pic . kneel on the seat and look down and below that switch and see if there is a small resistor there. maybe the resistor is burnt out or a wire is off . These wires and resistor is connected to the pump somehow as when I installed the wire , my 320 was working ok again . Hope this helps .
My machine does not stall at all. I checked the switch and checked to make sure all of my wires were good and tight. I've pretty much narrowed it down I hope to a seliniod valve on the manifold block next to the pumps but am having a hard time finding any pictures and or part numbers for the seliniod valve that is leaking. If I unplug all of the seliniods on that block the machine doesn't change state. It runs good and does not bog down or stall.
CAT 320L Has no power My CAT 320L has no power suddenly. When lifting the bucket under load or trying to excavate, the engine slows down and almost stalls so I have to stop and let the engine recover and then try again. It idles ok though. Ive replaced all the fuel and hydraulic filters. please help out and advise me on what course of action to take. I was browsing for solutions and came across your problem Cat man. Ill try what you say and then some of Bobs suggestions. Thanks.
Update:: it turns out that something in the computer is starting to fail... I was able to back feed power from the prv valve and suddenly came back to life with no issues and is still running correctly..
How did you backfeed the pro. I have same problem
I am having similar issue. This is a bypass for prv directly from the computer. Didn't help in my case.
Bypass
I spent more time on this problem and first set pilot pump pressure, then sweep test to see if prv goes the whole range, then calibrate prv. I was unable to meet the calibration specs for prv so I installed an old one that I had and was able to meet those specs and it works a lot better but I don't think it's 100%. When I go to calibrate prv it starts at 04 instead of 00. I don't know why? I think that based on sweep test that the controller is properly powering the PRV. Thanks for your input and let me know if you think of anything else, I have 2 of these 320's and they both have similar issues.
Does your automatic throttle work ok? The dile