Hi everyone looking for some help on where to start troubleshooting. My machine will only track properly ( rabbit or slow). if I am ever so slightly pressing on my stick to swing at the same time I engage my pedals. If I don't time it exactly right it will travel very slowly and rabbit won't engage. I have MP Dr. on a laptop if that helps. I know my one sensor is dodgy and Is being shipped as we speak. The code I got was pump 2 delivery pressure sensor. So I am replacing that sensor, the locking tabs are broken. Thanks. Tommy.
The pump delivery pressure sensor can cause issues with travel speeds. Sounds like you are on the right track (no pun intended ).
Thanks for the reply mg2361 But I have a feeling it's more than that. I will start with the sensor and report back. I have bigger fish to fry now so I will start a new post. Is there a way to lookup the part number? I take it genuine is the way to go. I was going to try fridayparts but the have sent me the wrong sensor already. Thanks Tommy.
Is it a possibility the 2 problems are linked.
The travel and my new issue with the swing locked up?
Yes
I'm not sure could you elaborate?
I suggest you check the items below. In particular, you should pay close attention to items Pump 1 control pressure and Pump 2 control pressure when you perform travel.
Is there a chance this is related to my swing issue in another thread? Also can I test travel if there is no gear oil in the swing motor?
What am I looking for numbers wise ?
Pump control pressure with full travel pedal should be around 3.4- 3.8 mpa
Pump 1? I get 3.6 MPA. It seemed to travel when I first started it today. And only wants to track faster if I touch the joystick a bit. One track is definitely slower too. Case drain test ? Left track in air with boom jacked. Pump 1 control 1.12. When I press stick out it jumps up to like 2.9 sometimes 3.2.
I assume you are testing the issue with one track jacked in the air ? Pump 1 supplies oil for right track …what’s the control pressure at full pedal travel (forward and reverse) Pump 2 supplies oil for left track …what’s the control pressure at full pedal travel ( forward and reverse) . What is the control pressure at full pedal travel and when you press to go stick out Pump 1… Pump 2…
Tracks on ground.both tracks traveling forward. Pump 1. 3.65 Pump 2 drops down to 0.02. same for reverse. Right track in air forwards 3.72 reverse 3.72 Tracking then stick out drops to 3.65 then back up. Left rack in air forwards. When I first hit the pedal it jumps up to 2.50 the drops immediately to 0.02. same for reverse. And pushing stick out it drops to 0.0 Hope this makes sense how I wrote it.
What is the travel pilot pressure sensor readings ? There is only one sensor so you will have to check each side and each direction individually
I will check that next. Won't be back to the machine till Monday.
One side in the air Left track forward 3.89 MPA Left track reverse 3.89 MPA Right track forward 3.89 MPA Right track reverse 3.87/ 3.89 MPA Both tracks on ground reverse and forward 3.89
See Schematic of the pilot signal manifold. When using left travel you have poor to non existent pump #2 control pressure. I suspect there is an issue with shuttle valve #10. The oil coming from the left travel pedal should shift shuttle valve #10 to the right. That same oil will then shift the pump 2 flow rate control valve sending variable oil to the control side of pump #2. .
I have never opened up a pilot signal manifold. Maybe @mg2361 could advise what you’re getting into.
Yep, I have had them apart. Lots of little screens (17) and shuttle valves (21). They like to scatter on disassembly. You have to be very careful and meticulous when disassembling so you know where everything goes on reassembly. The repair manual should have a location on all the screen and shuttle valve locations in case of a whoopsie. I know the picture in our manuals is grainy at best. If you lose any, then you have to buy the whole manifold because they don't sell the screens and shuttles separately. 99% of the time, when we find that the issue is in fact an internal shuttle, we usually replace the assembly.
I just noticed the (2) gaskets seem to be no longer available ! might turn into a *** show. Map of shuttles below. .
Is it a gasket that sandwiches the signal control valve together ? Can I use gasket maker? I do have a vinyl cutter that I have used to make gaskets before for some smaller carburetors but nothing too intricate.
Yes sandwich gaskets. Not sure what you could use instead. .
@J&R Con had a pilot signal manifold apart in June. He could possibly help with the gasket questions. . JD 270DLC Pilot Signal Manifold replace? Due to pump flow issues, overheating issues, and swing issues. I pulled apart the Pilot Signal Manifold on my hoe. Most of the spools has wear, with the worst being the spool for the flow on pump one. It’s actually scratch up a bit. New spools from JD run about $200 for all. Has anyone here... HeavyEquipmentForums
Thanks for all the info Diesel Dave. That's not for the faint of heart! I will see if my contact can source me an entire assembly. That's alot of little parts a first timer can easily mess up.
@Diesel Dave I swapped the entire assembly. Upon startup all functions worked as they should. Tracks in the air and travel was back to running good including rabbit mode. Same for both sides. Went to travel with tracks down and the machine went back to limping along. Right track in air works good still. But the Left track in air. No good. It seems like it wants to jolt at normal speed then slows back down. It will jolt like this forward or back like it wants to go then crawls slow when ever I let off the pedal then apply it again.
Does the pump 2 control pressure change when the left track speed cycles (jolts) high and low or vice versa ?
Yes it was jumping up and then not holding pressure. But when I run the machine at half throttle it will track in rabbit mode with the track in the air but as soon as I increase the idle to roughly 3/4 power the track bogs down and goes back to a crawl. It works fine until I pass the 3/4 throttle mark.
Does the engine speed affect travel performance when the tracks are on the ground as well ?
I ran out of time to try that. There are some slow leaks in places but hard to troubleshoot on my own. Was trying to record with my phone but nothing gushing out major that I can see. Spent most of my day trying to pinpoint them.
The machine will track in rabbit with both tracks on the ground at 1/2 throttle. As soon as I increase the throttle to 3/4 or higher. It goes back to a crawl. Pump 2 pressure holds steady in the 3.20 range. As you increase the throttle the MPa on pump control 2 pressure rises to almost 4.00 and then loses all pressure. I can recreate it again everytime just take feet of pedals lower throttle to half and it tracks like it should.
Using the same throttle scenario. If you can, monitor pump 1 and pump 2 control pressures at the same time and report back what you find.
Idle. P1 1.02mpa. P2. 0.93. 1/2 throttle tracks on ground moving in rabbit P1 3.32 MPa. P2. 3.10 MPa 3/4 -Full throttle tracks on ground in rabbit P1. 4.03 MPa. P2. Drops to 0.00 MPa
I assume when P2 control pressure drops to 0.00 the machine continues to track straight ?
Yeah not perfectly straight but goes back to a crawl.
I suspect the problem is produced at the Pump 2 Maximum Flow Rate Control solenoid valve. Its purpose is to set the flow at Pump 2 when using an attachment like a hammer where the attachment flow is preset in the monitor. It could be a mechanical issue where the internal spool itself is floating dumping Pump 2 control pressure. It could also be an electrical issue where the solenoid is receiving an unusually strong electrical signal from the Main Controller or a signal from an unknown source. As a test ,with key off unplug the solenoid #6 in the screenshot and see if the left track performance becomes more stable. Screenshot from the Operation Principal manual below.
Boom. Mic drop. This guy is good. With solenoid #6 unplugged we are back in business. Pump 2 Pressure holding steady. Tracking in rabbit mode again at full throttle. However it will slow if I try and use another function like boom up for example I can't recall if it was like that before.
WooHoo! good to hear. Now you can either find and fix the true issue …or not !! I don’t believe that particular solenoid is in the viewable data list on the monitor it may be viewable with your MP Dr, may help you to troubleshoot the electrical side.
This particular machine is plumbed for a breaker attachment and has some extra electrical "goodies". Installed. I will post some pics later. Could this be related? Or do I need to start with my MP Dr. ?
Do you know if it’s a factory plumbing kit or aftermarket? Interested to see the extra electrical “goodies“
I think factory but wouldn't know for sure.. But I do remember now that it was possibly the pump 2 sensor wiring connector was loose when I got the machine. I can remember plugging one of them in and cursing the shop that worked on it last. Please enlighten me at what I'm looking at here ?
Those are (2) aftermarket priority valves likely installed at the dealer. The priority valves would have been installed to run a brush cutter or other relatively high flow ONE way attachment. Priority valves allow you to use your dig functions (especially swing) and travel functions at the same time as the attachment is operating. I will have to think on how the installation and operation was signalling and controlling the swash angle of Pump1 and Pump2. The pieces mounted vertically on the black support are a pressure reducing valve and a shuttle valve.
The machine was recovered after being frozen in Lake Huron. It fits the classic description of rode hard and put away wet. Anyways those priority valves are disconnected. Would this affect my issue?
How much of the machine was under water ?? . I’m not too concerned about the priority valves themselves being disconnected. I am more interested with how the priority valve system installation was signalling and controlling the swash angle of Pump1 and Pump2. That portion of the install is likely still in place and a good potential source of the current Pump2 travel issue.
It was actually frozen in the lake. Up to the counter weight. Had to break away some ice to open the engine door to access the batteries. I might have some pictures on my old phone. So thoughts on where I should start looking to troubleshoot this? Pictures? Lemme know. Cheers!
Thinking about how the priority system likely would have functioned ,I can’t see it being a source of the current Pump2 travel issue. The priority system would only have been manipulating pilot oil pressure to each pump controlling the displacement of Pump1 and Pump2. The electrical side would have been pretty basic with a control switch, relay to power up the (2) priority valve solenoids and at the same time likely a remote pilot solenoid valve all run at 24 volts. . How high would the water have been in the cab ? Any major electrical components been replaced since being in the water ?
It would have been getting hammered by big waves before it froze up. I have had the interior trim panels all apart. Computer area looks good. I imagine it's possible it was up to the pedals. I think I see where you're going here. I have only replaced some sensors as far as electrical goes. The hydraulic pump was replaced by a shop with a supposed good used unit. They told the original owner it couldn't be rebuilt for some reason.
To me I want to say the current Pump2 issue affecting ONLY left travel is very unique and looking like it’s an electrical issue even more so unique. Potential water damage just adds more issues to the situation. I would remove the main controller behind the seat , open it up and see what you find.
Ohhh boy.... How many of you would send this machine to auction raise your hand . Be honest.
YUP ! You’ll be chasing that sh*t forever.
Understood. For now any harm just leaving the sensors unplugged ? I assume that is why it will still struggle to track fast and do another movement at the same time.
I assume you only unplugged solenoid #6 ? You could certainly leave it like that, though with solenoid #6 unplugged you lose the option of controlling flow volume to the hammer through the monitor. I want to say the travel speeds slowing while also using a dig function is normal. The right track is supplied by Pump1 and the flow combiner valve shift would allow for the left track to be supplied by Pump1 also. Pump2 would supply the boom function.