I was wondering if anyone could fill me in on how the auto idle function works on the d series excavators. Mine used to work, then worked intermittent, and hasn't the past year. The light on the dash will come on when I turn the switch on so I know I have power that far. I'm guessing there is a relay in the cab for it but can't find it on deere's parts site. I don't know where the machine senses the hydraulic flow or what part actuates the throttle. It's a pretty primitive system but electrics have never been my strong point.
I don't know for sure on these models but most excavators of this era use pressure switches in the various pilot circuits of the machine. They can be normally open or closed depending on the system. The switches are connected to a computer which decides if the conditions have been met to throttle up or down the engine. The computer then drives a motor to control the engine throttle. Someone should be along shortly to explain the components in more detail.
This machine has two small hydraulic cylinders that actually open and close the throttle. I just don't know where to start looking for the parts that actually decide whether to open or close the rack and how those cylinders are told to open or close
The 590D was one of the most bullet proof machines ever made.In 1989 it was in high demand because the next model up had a computer and no one, and I mean no one wanted to have anything to do with computers. The 590D has none. It has 2 pilot pressure switches(one for propel and one for dig) on the front of the valve bank which control the solenoids in the pump compartment which direct oil to the 2 little hydraulic cylinders on the throttle bell crank. One common problem was the switch in the cab would get all gummed up and not make contact.Easily fixed by removing said switch and spray it full of brake clean until it makes a good solid click.Then I would check the pressure switches and solenoids with an ohm meter for continuity. There are lots of videos on youtube that show you how to use a ohm meter. I have been an HD mechanic for over 45 years (22 years with Deere) and if I have anything wrong with my car that's the first place I go. hope this helps.
Joe Blow, not to start an argument, but what is the difference between a controller and a computer? The D series Deere had a controller that controlled, in part, the auto idle system. In my experience as in yours it's often the switch gummed up but after that I usually found an issue with the controller.
Tomato Potato. Deere /Hitachi called them a "logic Module" and the 690E had a microprocessor.The 490E and the 790E (dash 3) had a computer.The difference being a computer has readable memory and a logic module or microprocessor does not. They are all little boxes that you do not want to let the smoke out of. I remember when the first dash 3s came out and what a steep learning curve they were. Everybody always blames the computer when they run into a problem they cannot figure out but in my 22 years with Deere I changed very few of them.It most often turned out to be a bad connection or a sensor or a ground. By changing the computer you usually inadvertently fixed the bad connection.God help us all when artificial intelligence becomes the norm.
Joe is correct ! I've been with Deere now 29 years and have replaced maybe 10 controllers (that is computers, not logic modules) on "E" series Deere's. Every one of those controller failures were caused by a short in the wiring harness, solenoid or sensor. The logic module on the "D" series I have never replaced, yet (not too many "D" series left in my area). If the auto idle switch is turned on by the operator, putting the control valves in neutral energizes the auto idle solenoid after a 4 to 6 second delay. The timing circuit is in the electronic controller. As soon as the operator activates a digging or propel function, engine speed increases unless the mode selected was light duty mode. I attached some wiring info that might help.
Thanks a lot for the help so far. I was running it on a job last Friday and looked it over again. I'm pretty sure I saw the two pressure switches on the front of the valve bank. Back by the pump there is a small hydraulic filter and a small valve body looking thing that has either 3 sensors or pressure switches on it. That is where the cylinders for the throttle bell crank get their oil. What role do they play in the system? I changed the dash switch a few years ago, I was just assuming that since the idle indicator light went on and off with the switch that it was still functioning, am I wrong to assume this. You guys are right though, there aren't many d series around, they're getting pretty old. I ran one for a guy 14 years ago when I started operating. When my business got to the point I could afford an excavator I kept looking for a 590 because I knew what I could do with one, the reliability they had, and how great they were on fuel. Mine is a 94 and just turned 7k and still pulls a full bucket every time. I'd love a nice 160 but I'd also love this old girl to make me money for another 7k hours lol
If you turn your auto idle on and the green A/I light lights up then the switch is working. The 3 solenoids in the pump compartment where the oil comes from for the cylinders is called the solenoid valve block. The center solenoid I believe is the auto idle solenoid. I would still make sure you have good pressure switches first. That is the most likely problem for auto idle issues. If a switch is stuck the controller thinks there is a demand for hydraulics so the machine never goes to auto idle.
Hello, I just bought the same machine and I love it. The auto idle doesn’t work neither does the indicator light. I took the switch off and cleaned, then tested the wiring plug and one wire is hot with key on! Does it make sense to assume the switch is bad? I can’t kind a replacement switch