I have a Cat 308C CR that will drive around all day just fine. Use of the blade is fine too. However, when I'm using the bucket, I'll suddenly hear the idle control throttle the engine all the way down and the low idle indicator comes on. It doesn't matter where I have the idle control set, after that, it's just stuck at low idle. I turn the engine off, and do something else for a while, then I can come back and get some use out of it before it happens again. What would cause this? How are these features supposed to behave? I often like to work with the door open. Should that matter?
The door position doesn't have anything to do with the engine rpm, at least it doesn't normally. The auto idle feature normally will idle down the machine after the controls have been inactive for a certain amount of time, maybe 5 seconds or so. The engine should spool back up to whatever the throttle is set at immediately when any of the controls are moved. I don't have too much insight offhand on what is causing the problem without a wiring diagram, but the first thing one of the guys who does and has access to wiring diagrams is going to ask is what the machine's serial number is.
Should the low idle kick in when the hydraulic pilot safety lock is down? Is there an easy way to bypass the automatic low idle? Serial Number: KCX00653
From this site: https://www.justanswer.com/medium-and-heavy-truck/dd3y8-93-312b-excavator-auto-idle-will-system.html ...I've gathered that my problem may be due to a pressure sensor or wiring harness on the main hydraulic pump. Can anyone confirm this? How are these sensors supposed to work? If the pressure is too high, it's supposed to auto idle down? Shouldn't it idle back up as soon as I let off the joystick then?
Shouldn't make any difference. Provided everything is working the way it should work, the operation of the auto idle function is determined by:- a) whether the system is actrivated or not using the push button on top of the RH joystick. b) if it's activated aut low idle engages automatically if all the hydraulic controls (inc travel) are in neutral for 5 seconds. Switch it off.? Again using the push button on the top of the RH joysitck. It sounds as though you don't have an Operation & Maintenance Manual. Your current question and many more besides would be answered if you had one. Search the usual internet marketplaces for Cat Publication SEBU7613 or download one from https://catpublications.com/
My C model machines have a switch to turn the auto idle off. Not the switch on the stick Nige mentioned, but it is down on the console under your right hand. Auto idle on/off.
The attachment I posted above comes from the O&M Manual based on the OP’s machine Serial Number. I assume that it’s correct.
Sorry Nige, I didn't intend to contradict. I didn't actually read the publication you posted specific to the OP's machine. Both of my machines have a "master" switch located on the panel as well as the switch on the stick.
I know you didn't. I looked again at all the information regarding the OP's specific S/N prefix and there is no mention of a switch on the panel to the RH side of the operator's seat, although if I look at other S/N prefixes the switch is listed. #19 on the LH illustration below which is totally different to the control layout on a KCX-prefix machine as shown on the right. It really needs the OP to confirm the presence (or not) of that switch panel on his particular machine. I can only go from the illustrations in the manual. Thinking out loud I wonder if the push switch on the joystick could be weak and the slightest inadvertent contact with the button is activating the system.?
As to the button on the stick, first of all, I rarely use it, so I could be off, but I believe that button is only a momentary button. If you push it the machine will idle, but will immediately spool back up when the controls are touched. If you push the button while operating the controls nothing will happen, the engine stays at whatever it is set at. (This is the case with my machine, I don't have experience with others) The main reason I never use the button on mine is that the buttons on the sticks of some of those earlier Cats are a poor design; the actual button is under the skin of the control, so you have to push pretty hard and almost feel around for it.
Wow! Thank you for your help, guys! Clearly, I'm very new, and I'm feeling that right now. This is the first machine I've ever used, and don't have anyone around to show me the ropes. As Acoals said, the button on the joystick is under the skin, and, with the hours on this machine, all markings are worn off. So, I couldn't even tell there was a button there. Turns out I was just accidentally pushing that button without realizing it, and that was causing it to idle down. In my case, with this KCX prefix (2018), pushing that button idles it down and it stays down regardless of whether the controls are being used, and it will idle it down in the middle of use. It only comes back up when the button is pushed again.
I'm glad that you got to the bottom of the problem but by the sounds of it you could really use an Operation & Maintenance Manual, especially if you are planning on doing your own maintenance. You can get a genuine factory manual from here - https://www.servicemanualpro.com/?page=Products&searchbox=KCX00653 $49 + S&H in CD form, slightly more if you want a paper version.
I am curious, you said originally you had a 308C, which to my understanding should be early to mid 2000's era. I don't know about the prefix, but now it is a 2018? I wish the button on my 315 would force the machine to idle.
It's not I'm afraid. 308C excavator S/N KCX00653 was built on 3rd Sept 2004. If someone told the OP that the machine was a 2018 model then I'm afraid they were being somewhat economical with the truth.