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3.9 idling waaay too high

Posted: Wed Aug 03, 2005 10:54 pm
by igould
My 3.9 manual has been idling recently at around 2400rpm. It seems to occur at random from start up, either on gas or on petrol.
Sometimes it will drop in stages back down to normal if I get stuck at a red light for a long time, but mostly it just continues idling high.
This is not too good around town, but a real pain on muddy down hill descents.
Any clues?

Thanks,
Ian

Posted: Thu Aug 04, 2005 4:17 am
by fridgefreezer
Idle air valve sticking would be a good start - I think it's on the back of the plenum on yours. Unscrew, squirt with WD40, replace.

Posted: Thu Aug 04, 2005 9:12 am
by RaginRover
fridgefreezer wrote:Idle air valve sticking would be a good start - I think it's on the back of the plenum on yours. Unscrew, squirt with WD40, replace.
Two things, don't try and unwind it or open up the spring just use carby cleaner or wd40.

The other thing is if that doesn't work turn the Idle Bypass valve in 1/4 of a turn and see how you go

Tom

Posted: Tue Aug 09, 2005 10:35 pm
by POS
Also have you had the computer disconnected for any reason latly?

If so it could just be resetting itself.

It usually takes my buggy 30 restarts to get it right again.

If not, like the others have said, idle air control valve!

Posted: Wed Aug 10, 2005 8:55 am
by Philip A
I would be looking at a dirty throttle blade. Get some carby cleaner and give her a thorough doing .
Regards Philip A