Hi guys I have been lurking for a little while now while my partner and myself have been working through a whole slew of issues on multiple pieces of heavy equipment that we bought in a court sale. My name is Kevin and we are up in North Eastern BC. We have kind of hit a wall with the excavator and I'm hoping someone here maybe able to give us a push in the right direction from where we are at now. All the equipment had sat for a number of years (3+) while tied up in court and none of it looks like it was looked after prior to that time to begin with. This particular machine has been through a previous auction and a repaint at one time. It was not operating when we aquired it. The engine had at some point dropped a push rod and broke a connecting rod cap. Surprisingly it did not punch it out of the side of the block and the cylinder actually looked ok when I lifted the piston and the remains of the rod clear of the bore. We bought a new complete isuzu 4JB1 and installed it. The good news was that most everything seems to function the bad was it did not function very well and a short test run started to heat the machine up. Under load it will bog the engine and would most likely stall it but I have not let get there, this happens with all systems from digging in loose soil to walking it up a shallow grade to even turning on flat ground. Initially we thought it was the brake system dragging and we did and do have issues there. The brake release was not recieving any line pressure initially we traced it back to a wiring issue on the controll solinoids under the front corner of the cab. Once that was sorted out we get 550-600psi when the switch is engaged. Unfortunately we still get a park light indication that will briefly go out if you swing the house and relights within 1.5-2 seconds after you stop the swing. We have checked the final drive line pressure it was up over 3000psi with out any load. Setup up to read bleed down the brake pressure will drop from 600psi to 200psi in 2 minutes cold, when hot it will drop 200psi in 3 mintues or so and takes 15 minutes to drop to 200psi. We have pulled apart the final drives and inspected everything there was no dirt or debris and the fibers and steel (1) for the brakes looked good no discoloration or heavy wear and are not warped (being as the brakes were non operational due to the wiring being wrong a local HD mechanic thought there might be the possiblity of warped fibers and steels causing a continue drag). Reading through a lot of the other threads on stalling it seems it comes down to one of two things 90% of the time either fuel issues or pump sensor/wiring issues. The new engine came complete with everything including the oil filter new fuel pump, injectors etc. All fluids were changed along with filters when it was installed. At the same time we cleaned the whole fuel system replaced all the other filters on the machine and did a complete service. Yesterday we went back through the entire fuel system from end to end with no change in operation. When its under any load it will bring the engine to stall if pushed. The RPM will recover very quickly and there is no black smoke. When the machine is in the air and no load there is some change in the track speed with the park brake switch toggled on/off (faster with the brake in the off position) but under load it actually seems to have better power with the brake switch in the on position. Unfornately the sensor descriptions and locations are not the same from the machines I have been following on this site and thats where we could use a little help. We have tried to source a service manual for the machine and the only luck we have had so far is an outfit out of Austrailia that wants around 1K for the book. We have bought a few manuals that are a little pricey including a $400 dollar one for the Gradall telehandler we acquired but this one seems a little too steep. the only wired sensors on the pump are mounted on a bolted on flange at the front bottom of the pump that the main hydraulic line coming from the tank passes through. On the top of it is what appears to be a temp sensor and below that on the bottom side of the flange is a two wire sensor. We were told that the Komatsu PC75UU-1 is very simular and we did buy what was suppose to be a service manual for that machine but unfornately the book we recieved is for the PC75UU-2 model and does not seem to be much help at the moment. So if anyone can point me towards a solution to the stalling issue, where these sensors are located on this machine if it is using a simular system to the other machines or where I might aquire a service manual from for a reasonable price I would really apprieciate it. And I am truely sorry about being so long winded on this but thought I would try a save a little little time by letting you know all we have done to date with out too many Q&A sessions. Kevin.
We just finally got this issue sorted out with the excavator and I thought I would post the cure encase someone else can use the insight down the road. I turns out the Isuzu 4JB1 was off in its timing. although the engine came complete with everything including filters and oils in it, and supposedly ran after assembly, the timing was off by about 2* causing the the engine to run hot and keeping the machine from producing the power it should have. The engine would start fine and seemed to rev fine but the change of 2* timing from 19* to 17* BTC seems to have cured it. Now that its been sorted out we are starting a hunt for a hydraulic thumb to install on the unit. Kevin.
Thanks for the update Kevin. Always nice to hear what the outcome was. Even though I own a different machine, I think my general knowledge increases every time I read a post like this. Good luck on the quest for the hydraulic thumb. I would like to have one also, seems plumbing the boom is going to be an expensive proposition, at least more than I expected.