• Thank you for visiting HeavyEquipmentForums.com! Our objective is to provide industry professionals a place to gather to exchange questions, answers and ideas. We welcome you to register using the "Register" icon at the top of the page. We'd appreciate any help you can offer in spreading the word of our new site. The more members that join, the bigger resource for all to enjoy. Thank you!

Cat 308C CR Excavator Idles Down Randomly with low Idle Indicator On

Gravity

New Member
Joined
Mar 21, 2023
Messages
4
Location
Seattle
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?
 

Acoals

Senior Member
Joined
Dec 15, 2019
Messages
1,274
Location
Wisconsin
Occupation
Jack of all trades/Master of none
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.
 

Gravity

New Member
Joined
Mar 21, 2023
Messages
4
Location
Seattle
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
 

Gravity

New Member
Joined
Mar 21, 2023
Messages
4
Location
Seattle

Nige

Senior Member
Joined
Jun 22, 2011
Messages
28,984
Location
G..G..G..Granville.........!! Fetch your cloth.
Should the low idle kick in when the hydraulic pilot safety lock is down?
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.
Is there an easy way to bypass the automatic low idle?
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/
 

Attachments

  • Eng Spd Ctrl.pdf
    282.7 KB · Views: 4

Acoals

Senior Member
Joined
Dec 15, 2019
Messages
1,274
Location
Wisconsin
Occupation
Jack of all trades/Master of none
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.
 

Acoals

Senior Member
Joined
Dec 15, 2019
Messages
1,274
Location
Wisconsin
Occupation
Jack of all trades/Master of none
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.
 

Nige

Senior Member
Joined
Jun 22, 2011
Messages
28,984
Location
G..G..G..Granville.........!! Fetch your cloth.
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.?

1679585977747.png1679586071097.png
 

Acoals

Senior Member
Joined
Dec 15, 2019
Messages
1,274
Location
Wisconsin
Occupation
Jack of all trades/Master of none
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.
 

Gravity

New Member
Joined
Mar 21, 2023
Messages
4
Location
Seattle
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.
 

Nige

Senior Member
Joined
Jun 22, 2011
Messages
28,984
Location
G..G..G..Granville.........!! Fetch your cloth.
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.
 

Acoals

Senior Member
Joined
Dec 15, 2019
Messages
1,274
Location
Wisconsin
Occupation
Jack of all trades/Master of none
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 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.
 

Nige

Senior Member
Joined
Jun 22, 2011
Messages
28,984
Location
G..G..G..Granville.........!! Fetch your cloth.
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?
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.
 
Top