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Cat 304C CR Auto idle

Discussion in 'Compact Excavators' started by Danny L. Thomas, Apr 15, 2019.

  1. Danny L. Thomas

    Danny L. Thomas Member

    Joined:
    Apr 9, 2019
    Messages:
    9
    Location:
    Texas
    Looking for a little assistance. The auto idle on my 304C CR works like it is supposed to about half the time with no problems. The other half goes something like this. Start and warm up the machine, the indicator light for the auto idle is lit up. Lower the hydraulic lock out lever and the light goes off and the engine revs up and does not idle back down. Sometimes I can raise the hydro lockout and "slam" it back down anywhere from one to three times and the auto idle engages again and works like it supposed to. When the auto idle switch is engaged but the indicator does not light up while the hydro lock is in the up position, I can reach down and literally just touch the plunger on the hydro lock switch and the auto idle will engage. I then lower the hydro lock and the light goes off and the engine revs up. Other times, with the auto idle indicator lit, when I lower the hydro lock the light goes out, engine revs up, light will come back on and idle down, then light up and rev up again, not moving any hydraulic controls. I don't have a service manual and am not about to spend $450 to buy one but I can't see how the hydro lock switch has anything to do with the auto idle circuit, hence, just touching the switch making a difference and the randomly correct function has me stumped. I pulled the housing off the stick and checked all the connections and wiring and found no obvious problems. I can certainly just idle down manually but have this thing about all systems working properly. The other thing it does it start out working like it is supposed to and randomly stop working and the light go out sometime during operating the machine. Anyone have any idea what could be causing this?
     
  2. Nige

    Nige Senior Member

    Joined:
    Jun 22, 2011
    Messages:
    10,591
    Location:
    G..G..G..Granville...........!!
    Possibly a dodgy main harness connector somewhere..? I can see a couple, and the wiring for the auto-decel pressure switch is in the same "branch" of the harness as the manifold valve that controls the Hydraulic Lockout Solenoid. A Serial Number gets you the correct schematic - I was looking at one for an FPK-prefix machine.
     
  3. Danny L. Thomas

    Danny L. Thomas Member

    Joined:
    Apr 9, 2019
    Messages:
    9
    Location:
    Texas
    Thanks for the reply Nige. You are correct. S/N FPK03735
     
  4. f311fr1

    f311fr1 Senior Member

    Joined:
    May 12, 2016
    Messages:
    494
    Location:
    Middle TN
    Check these out
     

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