Hi all, Old CAT 330Ln, SN 8CK00054. Today, when we stopped to swap the bucket with the hammer, after starting the machine it now has 2 alerts showing on the display: a controller error and a monitor error. Please see pic attached (bottom right of the panel - sun was shining so hard to take a picture). Also the engine speed dial is not working. The alarm is also sounding. Is there something easy that we should check first or any common issues on these types of excavators before we have to go full blown diagnostics on this? Thanks Liviu
Hi all, I just want to give everybody an update on the situation - not sure what the interest is on a machine this old (it seems nobody replies to this thread) but I’ll go ahead anyway. The problem is actually intermittent, yesterday it worked fine after I posted, today it’s done it again a few times. I looked it up and there are 3 LED on the electronic controller mounted behind the fusebox. When it’s green everything is ok, when yellow comes on then the controller either has trouble communicating with the monitor or the monitor is not responding to the controller commands. If red then the controller is bad and needs repaired/replaced. Sure enough, when there is no error the led is just green but as soon as the monitor throws up the 2 errors for the monitor and controller, it turns yellow. What was different from yesterday was that when it threw the errors today the whole LCD was turned off, yesterday we had the gauges working. We will check the harness tomorrow, I’m hoping for a bad fuse or bad earth or some sort of short in the 2 cables that communicate between the controller and monitor. If anybody ever experienced this and knows any probable cause I would really appreciate the help - I’m sure you all worked on these machines before. Liviu
It sounds like you have a handle on what needs to be done. It's been twenty or more years since that machine was new. The harness connectors and contact points will have corrosion all over the place. One thing I do when I see those kinds of problems is a shake test around each connector. That the problem is intermittent, tends to make me think the display and processor are OK. Good Luck!
There is a member on HEF by the name of @anuradha who appears to be have a lot of experience on these systems. If he does not post in this thread I would suggest that you contact him by PM.
Before making the comment above I should've checked the location of @anuradha . He is located in Sri Lanka which unfortunately is experiencing a lot of political upheaval at the moment. He might just have other more important things on his mind right now. https://www.bbc.com/news/world-asia-61417972
Thanks for your help Nige. Hope everything is ok there the excavator was fine today, we’ll try and have a look on Saturday.
Hi, I looked at this thread after seeing Nige sir's PM. As explained above, 02 alert indicators on the monitor, yellow led on the controller represent the communication error between controller & monitor. First thing should check is the wiring ( 02 data lines between monitor & controller ) & relevent connectors. Check the connectors for corrosion. There are about 04 connectors to check including monitor connector and controller connectors along the data line. Spray some contact cleaners for connector insides if available. Check the 02 ground wires to the controller, whether it is providing good ground connection to the controller. If all these wirings and connectors are good, then the controller or monitor faulty, or both the components are faulty. As you said i assume that the engine rpm also couldn't control at that time using engine speed control dial knob. And you said that the alarm also sounded, then we can think that the controller is faulty. Because if the monitor is faulty and controller is good, there shouldn't be a problem for engine rpm control circuit. If the controller is faulty what will happen is, this communication error and other issues will arise more frequently in the future and at some point this communication error will stay continuously. So if the above mentioned wiring & connectors are all good, i suggest to remove the controller from the machine & carefully open the controller's top lid by removing 16 bolts around the controller's top lid.( be careful not to damage the rubber seal which is placed between the lid and the housing ) Inspect for any kind of visible damage or corrosion inside the controller. Inside there are 03 circuit boards parrelal to each other. On the top board there is a microprocessor, check its pins carefully as well. If the controller's inside is good, then change an another controller if you have another machine and see what happens. I think that this will be helpful to you some what. Good luck !
I have sent you the wiring diagram and checking procedures of wiring on this issue, please check your PM. And here i have attached some pictures of the controller inside, those are not that good in quality but i think you can get an idea by seeing those.
Anuradha - thank you! I’ll respond in more detail tomorrow when I am near the machine but there was some conflicting info regarding the knob - it continued to work even when the monitor was out so I am ruling the controller at the moment.
Hi, As you said, though the egine speed dial worked properly still we can't think that the controller is good 100% . Because it is a seperate circuit from the communication line. In this case if the wirings are good, then either monitor or controller is faulty. So it is better if you can inspect the inside of the controller to get an idea. If you have another machine in the site best thing is to do changing the controller or monitor to see what happens.
Hi, I only have a 325BLN and a 950F series II, I have a crusher with a 3306 engine but the throttle on that is manual by wire.
Hi All - update on the above situation. we did not get a chance to verify the wiring today because we are now experiencing another issues. The left track is getting stuck. It seems to do it when you are pressing the pedal to the floor, if you go half-way then it does not get stuck. Also when it gets stuck, the swivel (rotation of the cabin) does not work. The cabin rotation works if you rev the engine higher and then reduce or if you move the joystick a few times. I have no idea if this is related to the monitor/controller issues we are having. On this subject - it hasn't done it since I posted which is strange. Anyway when the track is blocked the controller LED is still green so not sure again if they are related. We had issues before where if you extended the boom and stick to the max it would bog down the engine and was releasing a lot of black smoke but for the past 2 months it hasn't done that ( it did it quite frequently last year). Any thoughts on what it could be? Please see video below of how it reacts. The right track works fine. I thought it might be an electrical issue but it has no pressure sensors on the track valves underneath the pedals. Thanks Liviu
That give me the impression of something broken or very loose inside the final drive itself. Were it mine, I would probably remove the cover on the final, or at least drain the fluid looking for shiny things in the oil.
Hi John, would that cause the swing to stop working though?
You have an old machine likely with lots of worn internal parts. It is likely you have multiple problems. The gear side of the final drive is not connected to the hydraulic system. However the hydraulic motor is connected to the swing motor by a case drain. Damage in the travel hydraulic motor might be able to enter the swing hydraulic motor through that case drain. I would suggest pulling the case drain and return hydraulic filters and check for brass or steel particles caught in the filters. If you find contamination, you are likely going to need to remove some components for inspection and possible repairs.
Hi all, they are going to look at the oil today hopefully - grasping straws a bit but if you look at min 2:52, when it swings left right, the track motor seems to want to move forward backwards. Could be nothing or something. I've found an issue with this but it's unlikely this information that came out in 1994 is still applicable as it worked ok for 28 years. It's to do with negative flow control... which I don't particularly understand but am making an effort by reading as much as I can on it.
Hi all, removed the oil from the final drive, there were no metallic shavings or anything in it, however the colour was of a grey-ish nature. We pulled a little out of the other side and it was black (in the white cup). The oil was changed this winter and the machine doesn’t have more than 250-300 hours since we changed it.
Negative flow is a system that shuts off the pump flow when there is no demand for oil. The main valve spools are all open center with a parallel passage. Oil goes through the valve and stops at the bottom. There is an orifice at that point which is connected to a hose that goes to the pump. When nothing is used that pressure is high and signals the pump to go to minimum flow. When a spool is shifted that pressure drops and the pump strokes up. Hope that helps.
Hi John - thanks for the explanation. Do you know if we can remove the cover of the final drive (the one with a lot of screws) to see what's inside without removing the track, final drive from the machine? Or would that not work. We are behind with our production and we need this excavator as it's the one which has the hammer so we're trying to figure out how to diagnose the issue while being able to work slowly with the machine while the parts arrive. Thank you!
Small update - it seems that the stick and swings are slower than usual. However, if you move the boom whilst travelling forward, both tracks work (albeit slower) and the left one doesn't get stuck. I've read somewhere that when you are travelling straight and use other commands it switches both tracks on the upper pump so that it travels straight. I'm thinking now it might be the lower pump but when a pump goes bad doesn't it just stop working? Maybe it's something that de-strokes the pump. I'm starting to hope that the final drive is indeed bad because if it's something in the valve control/hydraulic, I know for a fact we will struggle a lot with the diagnostic... unless I get some fantastic help from this forum as usual
Have you pulled the case drain filter and hydraulic return filters and checked them for shiny things?
John - can you tell me what/where the case drain is? in terms of filters e have identified three filters: 1 is the 4I-3948, the other one is 094-4412 in the hydraulic oil tank and there is also a 3rd one 108-8713 (also in the tank rom memory - this was very hard to find/order as it's not usually listed in the filter lists). Which one should we be checking?
I don't know the numbers that you are giving. The case drain filter is in the pump compartment usually mounted next to the hydraulic tank. The filters in the hydraulic tank are the return filters. Follow the hoses from the filter cartridges to where they go to. The third filter you are describing is likely a fuel filter.
Hi all, Small update - we had somebody in to look at the machine but there wasn't a great deal of success. They measured the inlet pressure on the pilot oil manifold and it measured around 35 bar (around 500 psi) which they said is within spec. They suggested that we focus our attention on the hydraulic accumulator which is mounted to the manifold but they didn't have equipment to measure it so we're on a bit of trial and error. From what I have seen, even if the hydraulic accumulator would be shot, I cannot find a logic why the right track works fine and the left one doesn't. Even if you run it individually (so you are removing the need for the accumulator to provide makeup oil) it still gets stuck. I have attached a picture with what I am referring to, you can see the line they used to measure. They tried adjusting the pressure on the relief valve to 40bar just to see if it makes a difference but the valve screw snapped so we let it alone. We did however solve some conflicting information and I can confirm without doubt that if you lift the track in the air then it will not get stuck. Today we cut open the 2 filters. The hydraulic tank return filter is clean, however the pilot filter do have metal shavings - we think it's not that bad as they are quite fine and cannot see any copper particles but then again we are no experts - you might say it is a disaster. We are thinking that the machine is 29 years old however the pilot filter has less than 300 hours if that makes a difference (we changed some of the hydraulic oil in the winter, when we replaced the filter) but we couldn't do a proper flush of the system. Maybe these fragments were caught up in the old oil and have just recently been displaced. Please see pictures of the two filters. Any suggestions would be more than helpful.
Lots of small particles in that last photo. 300 hours is not a lot of hours for the amount of metal on the paper. The accumulator only allows you to lower equipment to the ground if the engine dies with it in the air.
Thanks John - what would be the next step?
I don't remember if that machine has a separate pilot pump or not. If so, I would probably remove it and tear it down for inspection.
Yes it does have a seprate one, however my judgement is currently excluding pilot pump issues as the right track and all other commands work. I’m not saying the pump isn’t bad or worn, but wouldn’t it be more likely that this is a control issue? From what I’ve thought so far I can only think this is a control valve issue or a lower pump issue (that drives the left track) however the return filters were clean so I’m tending to exclude the lower pump?
I would suggest you put a gauge back into the pilot pump circuit and check the pressure as you are using multiple controls at the same time. If the pressure drops at all below the set pressure when not using anything, you have that as a problem. The description of your original issue sounds like a spool not operating as it should. A failing pilot pump putting debris into that system can make the pistons in the pilot control valve or the main control valve get sticky.
Hi John, I told a lie, it’s not seprated per se, it’s within the main housing where the upper and lower pump are. Just for my knowledge, wouldn’t the pilot filter capture the debris anyway so the spools in control valves wouldn’t be contaminated?
That is a common misconception. The filter only traps what are commonly referred to as "dogs, tree branches, and small children." Not the smaller particles that can really do damage to valve spools (amongst others) in other words.
All filters have some kind of bypass function for when oil is cold. Start up after a cold night and maybe most of that oil is going around the filter.
solved the controller problem with programmed obsolescence camouflaged capacitors with a resistor inside... I attached images and if I could here the video of the machine operating at 100%
Hi just saw your post. The issue IMO is that the pressure switch is not getting activated for the ECU to command the PVR or the PVR solenoid itself is stuck or inoperative. So try this. you can switch to manual mode by flicking the switch behind the armrest from auto to manual. Next you can set the pump flow to low or high using by flicking switch to tortoise or hare. you can then control the engine stepper motor manually flicking the up and down switch. if the hydraulics are quicker then you have a problem with the PVR part of the circuit. to check the pressure switches (these are usually green or black 2 wire switches on the control valve). Unplug them and short out the two pins. You can just put a small sharp pin through the wires as well. this tricks the computer to think that pressure switches are activated so the PVR should open up and problem goes away. I think this model had pressure switches for each half of the main control valve. Try and let me know I can let you know next steps which would be to check the PVR and a a couple of other solenoids which control the travel speed etc.
Hi all, will post a few updates as it’s been a long and painful and unsuccessful month so far with this. Keep things short, we have opened this valve section and found the sleeve to be broken in half. All other components looked ok. We bought just to be safe valve + springs + plunger + sleeve all new. Received everything except the valve today, changed the sleeve which was broken, swing and stick function better (the swing doesn’t get stuck anymore) but track issue is still there so I’m certain it’s not this that is causing this. We will put the new valve when it comes as well just to say we’ve completey done this change.
Right, moving on from this CAT came to see the machine but didn’t really solve anything. Their work statement says: - Checked pilot pressure from pedal and pump to control valve - all ok - Checked left track plunger - all ok - Checked implement and boom raise pressure sensor - both defective - we changed them - recommended for us to check slow check valve - we’ve done this and it is ok they did not have a flow meter only pressure gauges. We’ve since change both pressure sensors (1 was genuine CAT and the other aftermarket) and there has not been any change to how the machine works, track still gets stuck. The AEC seems to be dropping the engine rpm correctly when pressed and no load and then as soon as you move something the engine accelerates - this was not working before. Now - in practical terms: - the left tracks works ok once in the air, as soon as it is on the ground it gets stuck as in the video. It works regardless of Power Mode - swing does not get stuck anymore since we replaced the broken sleeve - the excavator functions perfectly if the engine dial is on 7+, as soon as it is below 7 it gets stuck. It travels, loads, does everything as if there was no issue with it if rpm is above 7. could it be the PRV valve? Negative flow control, pilot pressure, pump issues make no sense anymore if everyrhing is working when the rpm on the engine is high. Attached pictures of the two switches on the control valve block we changed (the green ones). any suggestions please fell free
Looks like your pressure relief valve for travel motor is busted. So it’s not building up pressure. You can stick a metal rod to jam the sprocket and run the motor with pressure gauge attached to see if the pump pressure hits I think around 4000psi. Gotta check the spec for that. But since you have looked at pretty much everything else it seems like a pressure relief valve faulty on the left final drive motor.
If both pumps are hitting target pressure when arm is fully in and boom up both levers held to relief pressure with engine rpm at high then it would seem certainly like the travel motor pressure relief valve is busted. Could be just o rings are leaking on them so could be a cheap fix.
Hi, the operator which went with the CAT guys said they measured the pressure at the travel motor and also on the pilot line. When the track gets stuck the main pressure drops to zero but the pilot pressure stays the same. He seems to remember that it was around 4000 psi before it gets stuck. This is where he thinks CAT have measured the main pressure in the track motor. We have seen leaks there in the winter. But if the pressure valve is busted why could it working for 2-3 seconds and then the track stops as per the video. Also what would be the connection with the engine dial above 7?
They measured the pump as you said with the boom uparm in levers to the max and they were ok. I have to emphasize they only had pressure gauges and not flow meters, but I guess we can rule out the pumps
Could be that the relief valve is not holding the pressure. Usually you would have to do a case drain test to verify if that motor is worn as well. Could be the motor pistons are worn. Typically we see mainly relief valve and worn pistons for this type of issue.
Any tips on what should we try next then? Should we try to take the valve apart? Anything special we need to pay attention? also is the PRV avenue closed? It made sense what you were saying with it sticking, my only other question on that would have been that the POwershift line is common for both pumps so wouldn’t they destroke together, hence why I couldn’t explain why the left would stop but right would go. Although it could be connected with the engine rpm dial making it work if above 7. Thanks
Just a small update, the swing function continues to lock-up as well. I believe this and the track getting stuck must be connected somehow. Will continue to read and try to understand what it could be.
I can only think of the pilot pressure or flow getting cut off due to a weak pilot pump. Could also be pilot accumulator. But would be worthwhile checking what happens to pilot pressure when the issue arises. If the issue is replicable all the time that's a good thing as you can make sure you fixed it!
have you checked pilot pressure when you have the problem? Could be a pilot line relief valve misbehaving etc
if you want WhatsApp your number we can have a chat on what you've done so far and see if we can help with where the issue is.