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John Deere 490D problem
- Thread starter heyu29h
- Start date
overworked
Senior Member
Sounds like u might have left a rag in a line u had off, remove and inspect return filter and u will probly find fibers from rag. If so ,not a big deal, remove and clean relief valves and posibly main spool for the boom line u had off. Not a big mistake , we have all done it before.
Thanks for the reply
I don't think anything was left in the line, but figured it would be easy to check that filter so I pulled it. I checked the return filter and found nothing there. I even took out the filter and tried it, but the machine worked the same.
As I mentioned earlier, when you try to raise the boom or push the arm out, it creates pulsing vibrations. When you push the arm and curl the bucket some, it moves a little better (still pulsing some, but not as much) (and slowly). Without curling the bucket, it will not really move at all. The swing will swing slowly without pulsing. Auxiliary hydraulic thumb works slowly without pulsing.
I don't think anything was left in the line, but figured it would be easy to check that filter so I pulled it. I checked the return filter and found nothing there. I even took out the filter and tried it, but the machine worked the same.
As I mentioned earlier, when you try to raise the boom or push the arm out, it creates pulsing vibrations. When you push the arm and curl the bucket some, it moves a little better (still pulsing some, but not as much) (and slowly). Without curling the bucket, it will not really move at all. The swing will swing slowly without pulsing. Auxiliary hydraulic thumb works slowly without pulsing.
rgl726
Well-Known Member
Thanks for the reply
I don't think anything was left in the line, but figured it would be easy to check that filter so I pulled it. I checked the return filter and found nothing there. I even took out the filter and tried it, but the machine worked the same.
As I mentioned earlier, when you try to raise the boom or push the arm out, it creates pulsing vibrations. When you push the arm and curl the bucket some, it moves a little better (still pulsing some, but not as much) (and slowly). Without curling the bucket, it will not really move at all. The swing will swing slowly without pulsing. Auxiliary hydraulic thumb works slowly without pulsing.
this symptom is angle sensor problem. check your angle sensor.
try to remove the connectors of the 2 pump displacement solenoid and try to operate the machine.
tell me what is the movement.
rgl726
Well-Known Member
Ok. Sorry for my ignorance, but what area would the connectors of the 2 pump displacement solenoid be? In the area of the hydraulic pumps or the main control valve. Thanks for the tip and help.
this is on the top of the main pump.
Ok, I'll look for this. Wouldn't functions that are on the other hydraulic pump function at full speed and not just slowly if this problem had to do with just one pump? Unless the pump you are referring to controls the pilot controls...
rgl726
Well-Known Member
Ok, I'll look for this. Wouldn't functions that are on the other hydraulic pump function at full speed and not just slowly if this problem had to do with just one pump? Unless the pump you are referring to controls the pilot controls...
There are 4 sensors that monitor the system and tell the computer what is happening so it can control the pumps.
#! N sensor, this is the small sensor on the top of the hyd pump that monitors the RPM of the engine.
#2 P sensor , is the sensor on the outlet port of the pump that monitors the pressure that the pumps put out.
#3 A sensor, the small can shaped sensor on the side of the hyd pump, this monitors the angle of the swash plate inside the hyd pump to tell the computer how much oil the pump is tying to put out.
#4 DP sensor , is the can shaped sensor on the top and in the middle of the control valve. This tells the computer the difference in pressure between what the pump is putting out and what the valve bank is using.
If the wiring to any of these sensors is bad or the sensors are bad or the fuses are bad all of your pump control is lost and many problems can occur.
Last edited:
I tried unplugging the connector and got the same result for the machines movement. I checked fuses. Some looked to have some corrosion, so I put new ones there. One of these was the EC Motor fuse. I noticed it did a slight spark when I attached the new one (the machine and key was off). Does EC Motor deal with the hydraulics? Could there be a short?
Thanks
Thanks
You said EX160-5. You have no High Speed Solenoids, no A sensor and no DP sensor on that machine. It sounds like you have something stuck in the main relief valve. The pulsing does not sound good. Could be you have a pump starting to fail. I would pull your main relief valve mark it very well, take it apart and see if you have something stuck in the poppet/seat. Secondly I would again take your return filter out and run a magnet at the bottom of the cavity to check for any metal.
The relief valve is on the bottom left forward of this machine. Check the technical manual you said you looked at.
The relief valve is on the bottom left forward of this machine. Check the technical manual you said you looked at.
PhilipJMcclain
New Member
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