We have a 1993 John Deere 490E Excavator the we bought in 95. It has around 9800 hours on it. We recently had our engine out for rebuild. After reinstalling it we have encountered hydraulic problems. The speed is fine, however when putting any really pressure on any certain cylinder except the swing or tracking it will choke the engine down and kill it. This happens at an idle or full throttle. All fluid levels are full and filters are new. This seems to be an electrical problem and not engine or hydraulic pump. Any help is much appreciated and I will gladly drink a beer for you.
Did this happen before the rebuild or only after. If it was after check the fuel system first, check all lines and make sure they are clear and tight. At the lift pump where you would have disconnected the fuel the fittings are soldered on and if a back up wrench is not it will crack and cause the pump to suck air. Also when you removed the engine what else did you disconnect on the electric/ hydraulic side?
It's not a fuel issue. You can curl the bucket in with the bucket empty and it kills the engine. It never did that prior to pulling the engine. I had all five plugs off of the pump. I ran it today and was just doing light work with it. Pulling brush and very small trees out of a fence row. Biggest tree was the size of my ankle. Suddenly the hydraulics quit. Engine kept running.
The curling of the bucket and the engine stalling can be fuel issue but the hydraulics quitting and the engine staying running like that is not. Did the hydraulics come back after they stopped? If they did. Check the angle sensors on the pump and make sure they haven't moved, if they go over voltage they will shut off the hydraulics. Check all the connections and make sure they are where they belong and that they are connected fully. What do you mean you pulled all five plugs off? I usually hang the pumps with a bar and ratchet strap or take them with the engine .
It's not a lug down fuel starvation kill. It's abrupt. Very quick and sharp killing of it. The hydraulics did not come back on. I unplugged all five plugs and pulled the pump out after I pulled the engine to clean out the mud. It had not done this prior to pullin the engine.
Sorry when you said plugs, I thought you were talking about a hydraulic blanking plug and not an electrical connector. You are 100% sure the connectors went where they came off from? Do your joysticks feel like they would when the machine is turned off?
Joysticks feel normal. I've had the hard feedback feeling in them before. Yes my apologies connectors lol. Is the angle sensor the one on the right side(fuel tank)? Three wires coming out of it?
Its just terminology, where the brain connects the dots. The reason I asked about the joystick was to confirm the pump coupler didn't split and it sounds like it did not. The angle sensor is the one by the tank. If you are going to take it off mark it first and use it as a reference when installing it as it is adjustable. It could be the rpm senor on the pump or the pump proportional solenoids also so you need to make sure everything looks good before going too far. Look for any damage to the sensors or clean areas around the angle sensors. Its easy to bump things when those pumps come out.
I haven't pulled any sensors off but I did bump the pump around pulling it and reinstalling in on the engine. I put a new coupling on before putting the pump back on. Is there a position the angle sensor should be in with the engine turned off? Is there a procedure?
Expensive coupler on these older machines aren't they. See this link for adjustment. HeavyEquipmentForums
Around $900 Thanks for the link Is that known to stop the hydraulics?
Yes it can overshoot and then the computer goes from seeing lets say 4.5vdc then when it over shoots now will read 0vdc I have done it manually with a computer connected. The other solenoids and sensor at the pump can also cause it but this is the only one that is adjustable other than the rpm sensor.
Hi I as well replaced this part on my 490e and the engine still bogs down all the components are good as well as the pvc except the pvc is getting power in and giving some power to the pump and when we put the sensor in it worked for about five minutes then it started doing the same thing again. If anyone has any suggestions I would love to hear them.