FJ62 high idle back with a vengeance. Update, new mystery, 2nd update. (1 Viewer)

[Saucerman]

I’ll freely admit that I haven’t analyzed the whole thread but…
I was sticking high idle after pulling out the auto trans. A combination of de-activating the dash pot and loosening the accelerator cable did the trick.
The springs at the TB were set assuming some snap back tension from the kickdown cable which is no longer in your rig.

Yep, me too, have done both. Still mixed results. It may be the cable, maybe not though. It may be I need a stronger spring or something to help snap the butterfly closed definitely every time. I have to play with it some more.

 

[Saucerman]

New cable, added small spring to throttle. Problem still persists. For those in the know...is there something other than the mechanical throttle that could keep the throttle open? I can still blip it to drop the idle. I can even blip it while in gear and I can feel the idle drop if say I am coasting in 4th. The TPS was set to factory spec. The isc never quite made me happy when testing it, but it did move just never by much. I just don't know if I need to tear into the manifold again. Thanks for looking this over with me.

 

[pithicus]

What happens if you push the butterfly mechanism towards closed with your fingers when it's idling fast? If it slows down, it may need an even stronger spring.

FWIW I've had 2 aisin carbs that did this. Not throttle bodies but same principle. Something about the way the bushing wears stops them from closing properly. I would liberally spray wd40 on them and it would fix it for a while. The only fix was a stronger spring.

 

[Saucerman]

Thanks @pithicus I will give that a try. When you mean a stronger spring you added a spring in addition to your existing springs? The TB spring would be a bear to replace. I was thinking about adding another return spring where the kick-down cable used to be.

 

[pithicus]

you added a spring in addition to your existing springs?

Yep, that's what I remember doing. Extra spring on the old kickdown cable linkage would be fine also.

 

[Ned]

Oh yeah I checked the dashpot alright. I removed that POS when I removed the erg. It was non functional anyway. The truck is now a 4speed too, so no auto trans to worry about.

I am chasing an intermittent high idle as well on my 85 FJ60 / 3FE swap as well. I still have the dash pot on mine, but it is de smoged otherwise. I haven't seen any info on deleting the dash pot. Do tell. What did you do to delete it?