I've been helping a friend with a John Deere 690 E series Long Carridge Excavator. We are getting a flashing light in the control modual on number 8 in the second test mode. Comes up Heavy Lift Relay / and Low engine speed. The machine will dig when it is cold. All the functions seem to work only it slows down as the machine warms up. The engine runs at proper speeds so it is not the engine speed solenoid. I have a Servicemens book but it does not descibe what the Heavy Lift Relay circut is? The engine speed magnetic pickup is good and tests 28 olms as it should. The Hydraulic pump has been taken apart and checked and is in good service. The power Solenoid has been replaced. The solinoid on the pump has been tested and is good. It is the earlier serial series # 542081. We have taken apart the relief valves and the springs and spools look good in both the diverter valve on the top of the pump, and the main valve with the power solenoid. Anyone have any ideas. Stumed in Crazyville. Dandy Dave!
I would check engine rpms with a tach if you have not done already, rpms on top end go out of range pumps will decrease slowing hyds. I believe Heavy lift relay is same as power boost relay out in battery area 3rd relay in from outside.
I wondered about the heavy lift relay and power boost relay being connected. John Deere gets an F for not explaning that in the book. There should be flow charts for this stuff for the price of the manual. Thanks. I'll let you know how things go when I get back there. Dandy Dave!
I 2nd that jw......check rpm's with photo tach....... The speed sensor on the unit can become faulty as engine warms.... Good luck:usa
Yess sir. Will do. Love them Dallas Cowboy Cheerleaders Mr. Komatsu. Thanks for the advice all and I will let y'all know how we make out. Come to think of it, when we pulled the pump there was a rats nest in the housing and I cleaned it out. I pulled the speed sensor a few days ago and there were some filings on the end of it, I cleaned the filings off, and tested the olms then which tested good. But like everything else, an olms test alone is not 100% fool proof. Thanks again everyone for advice. Dandy Dave!
There is a little bearing on the end of the injection pump actuator. When you go and look at it,there will be a flat spot worn into it from where it presses against the linkage. When you replace the bearing she'll be happy again. p/n jd10181 http://jdpc.deere.com/jdpc/servlet/...HomePageServlet_Alt?search=model&model=690elc
OK. I'll check that also. Thanks, Dandy Dave!
Dave check your heavy lift control for a bad switch. When an excavator goes into heavy lift, the main relief is set higher for heavy loads and the pumps are destroked to minimum for fine control of the heavy load you are moving. Later Bob
where is the heavy lift control located?
You should start a new thread and list your machine and serial number. This thread is from 2012.
Brian, check your pm’s