Hello there, I'm having troubles with a Johndeere 490e excavtor. The machine is a 1996. The problem I'm having is with the stick boom. I move the joystick, and the boom is very slow to move, both in and out. All other functions seem to be fine. The seal kit in the cylinder seems to be good, the boom doesn't creap down at all. I have had the spool out of the valve bank, seems in good shape. I swaped the relief valve from the main boom, main boom worked good, the problem stayed in the jib boom. I swaped the pilot hoses to the other joystick, but the problem stayed in that boom. I find when i use another fuction, like open the bucket all the way and hold it, the boom will work not bad, but alone the boom will not work good at all. Is there something somewhere that tells the pump to send oil to the function, and the message is not being sent here? Would pressure switches do something like this? I'm at the end of 'er here boys, I don't know where to look next:beatsme :Banghead
490E is a very fast machine when setup right, it has an angle sensor that can ruin your day if not adjusted properly. You have a couple options for adjusting this sensor; one is multimeter or DR ZX. I assuming you dont have DR.ZX (or DR EX, etc..) so multimeter is going to be the way to go. The angle sensor is a large round sensor mounted to the pump on the side, its a three wire sensor. So you need slightly loosen the two 5mm allen head screws just enough so you can turn the sensor. Then probe the black wire and the white wire I believe, set you meter to DC Volts and read voltage. Turn sensor until you get 4.40 +.05 volts on your meter, if you get no voltage keep probing until you get voltage and are able to make it change by turning the sensor. If you cant get any voltage or adjustability you may have a bad sensor or wiring issue, you may even have a controller issue. Remember CHECK YOUR FUSES! Good luck
I freely admit I'm no expert on the 490E, but I fail to see how his problem can be with the pump angle sensor if his trouble is with stick operation only. :beatsme
Im with atco here, if you have swaped things at the valve chest and it still dose the same id be looking at the cylinder! seals!! scores in the barrell, bent rod etc! Aiden
Without cycle times we don't know what is really working correctly or not, in my experience most all operators only catch the main or worst issue and miss several other minor problems. 490E is not known for mistracking do to the one pump, so that can't help us. Arm and bucket aren't nearly as demanding as the boom cylinders so a slow cycle time on those functions can be easly missed. So that brings us back to the boom, it will be the most effected by a mis-adjusted angle sensor thus the operator notices it the most. I more than willing to bet that other functions are below cycle time spec, adjusting or checking an angle sensor is much easier than dropping boom cylinders down and inspecting. I always check the simple stuff before tearing into machine. As a technicain my time is spent 60% of the time on my computer, and solve 50% of problems using it. This very well could be a piston bypass issue on one of the boom cylinders, however adjusting an angle sensor first is where I would cerenlty go first and do all the time. My method of diagnostics is always K.I.S.S (keep it simple stupid) this helps me stay organized and not overthink simple issues. Otherwise I could tearing into a bunch of components for no reason.
The A sensor adjustment is done at max swash angle only! If your stick is the only slow part I would look at your Variable Pressure Compensating Valve (vpcv) system. A little information about how that system works. When you activate a function (we will use stick) the spool on the valve bank moves in response to the amount of movement on the joystick. Now here is the fun part on that style machine. The inputs to the Pump Valve Controller (PVC) from the Pressure sensors, DP sensor, Angle Sensor are read by the PVC and the PVC sends a signal to the High Speed Solenoids to stroke the pump and to the VPCV for stick to open and allow oil to the Stick spool. So if you activate the stick and the pilot oil goes to the Stick spool stroking it, this does not mean any significant oil is being allowed to go through the spool to move the cylinder. Unless the VPCV is getting oil to it. If you look at the 2 hoses coming off the valve bank going to the stick, there is a plate with Allen bolts in between the 2 hoses. That is the plate holding all the VPCV in it. There will be steel lines going into it for each function. These are the pilot feed lines from solenoids that control the amount of oil to the VPCV spool allowing oil from the pump to go to the stick spool. Hope that helps you understand the system. Here is what I have commonly seen. 1) The solenoid that feeds the steel line that goes to the VPCV is sticking mechanically due to a varnish build up on the tiny spool. I have pulled it apart and cleaned it and all works ok. The solenoids are adjusted so don't play with swapping them around or playing with the adjusting screw. 2) The VPCV and the PZ orifices are leaking behind the plate. Sometimes the Allen head bolts are broken off because of leakage pushing the plate off a bit. There may be no external leakage present. If you get into taking the plate off look out. Many parts and pieces that MUST go back exactly in the same hole they came out of. Springs can be slightly different PZ orifices are different etc. 3) I have seen the VPCV spring on the back of the spool broken. You have to take all above apart and the VPCV spool out and fish the spring out. Deep inside. Good Luck
Yes make sure you pull the to Displacement solenoid connectors before adjusting angle sensor, they are mounted towards the top of the pump on the same side as the angle sensor. When performing boom raise make sure arm fully stretched out and bucket in level position, start with bucket on ground and pull boom raise all the back until cylinder stop. Measure and post times here, do each test at least 3 times per function. Oil Temperature 50 ± 5°C (120 ± 10°F) Power Mode Speed ’P’ (Max. Power Mode) Work Mode ’M’ Speed General Purpose I Test Course Length 20 m (65 ft) Boom Raise-Max Cycle Time 4.3 sec Arm In-Max Cycle Time 5.5 sec Arm Extend-Max Cycle Time 3.6 sec Bucket Load-Max Cycle Time 3.4 sec Bucket Dump-Max Cycle Time 2.6 sec Swing Left or Right, 3 Revolutions From a Running Start-Max Cycle Time 21.7 sec Propel (Check in Both Direction): 20 m (65 ft), Max. Speed Propel Cycle Time 13.0 ± 1.0 sec Propel (Check in Both Direction): 20 m (65 ft), Normal Speed Propel Cycle Time 21.0 ± 1.0 sec Propel (Check in Both Direction): 20 m (65 ft), Super Low Speed Propel Cycle Time 29.0 ± 5.0 sec Propel (Check in Both Direction): 20 m (65 ft), Track Raised at Max. Speed Propel, 3 Revolutions From a Running Start-New Cycle Time 14.5 ± 2.0 sec Propel (Check in Both Direction): 20 m (65 ft), Track Raised at Max. Speed Propel, 3 Revolutions From a Running Start-Max Cycle Time
im kinda of having the same problem with my 490e we have changed some lines around. the problem still stays with the boom where ever you put it it wont move out but it will move in toward you and every thing else works great HELP PLEASE!!!!!!!!!
Thank you fellas for all the advice. KenAl, I believe your on to something here. This sounds like it could be the problem. Dbarron, you are right as well, I don't know the proper cycle times, because I haven't been around the machine enough to know. To me, the other fuctions seem fine. Track power was messed up a bit. I replaced the seals in the rotatry manifold, they were bypassing and leaking. I really don't think the problem is in the cylinder, but I've been wrong before. jlange, stay with me here, I'll let you know what we find as soon as we find it. I've called in a John Deere mechanic. I think we're going to go at it this weekend or the first of next week. We put it on the '' back burner'' so to speak, but it's time to get'er goin.
did you fix the problem?
The post has started in 2011!!!