Surely you're a clever mechanic? (Answer my Q, and I won't call you Shirlely again!)

[TreeHogger]

Economy and High Output mode and idle speed eratic/intermittent/mischievous - 490D

Greetings - 'thinking maybe a seasoned mechanic or operator here may be aware of a common problem, for a place to begin looking for a repair. My 1990, 490D Deere frequently does not come off idle when one turns the three position switch from idle to economy or high output work mode.

It seems as though it gets 'tricked' (sometimes) into working if (with the switch not in idle mode), you engage the tracks - but only if in Rabbit and never in Turtle.

Additional clues:

Once it is working, you can switch between eco and idle and it seldom fails to cycle between the two RPM settings...

~ High Output seldom works ever (though I don't try it often)

~ Auto Idle seldom works either

~ Once, it was 'stuck' in idle mode at start up, with the switch in the center position (economy), and I 'rolled' all the fuses with the palm of my hand, that seemed to work...

~ It always idles nice.

Might this be the switch itself, a stepper motor(s), a electrical connection, sensor? Mechanical linkage? Other??

Thanks for any ideas, I do have the repair manual...

Mark

 

[TreeHogger]

Whaaa...? No replies?

Was it something I said?

(Seriously, no one's got ideas/experience???)

 

[cutting edge]

It could be one or more than one of a few different problems. (PVC,switch panel,wiring harness,ec motor or sensor,throttle cable)

The first thing i would do is clean all electrical connectors involved,including fuses and fuse holders,check for flash codes on the pvc abd do an ec motor learn.

will add instructions later when time permits.