thetundrawolf

My friend bought a 4 Runner that we discovered had a throttle stop screw that was turned in quite a ways just to get it to idle.

We bought a new TPS sensor for it, and adjusted it.

We also replaced his Auxiliary air valve.

Except it idles real rough, now. The idle speed adjustment (not the throttle stop screw) when I turn it all the way in, it idles at about 900 RPM. If i back it out past that it wants to idle at 2,000 RPM.

If I disconnect the tube that goes into the intake manifold from the AUX air valve the engine will die.

But... If I hold my thumb over the nipple that goes to the tube from the AUX air valve, the vehicle idles fine. Shouldn't it stall out if I cover that tube? Do I have the throttle stop screw too far in?

osv

where is the throttle plate set at when the motor is idling? it should be barely cracked open.

thetundrawolf

I took the throttle body off of the intake when I adjusted the TPS, I may have turned it 1/3 instead of 1/4 but it's barely open at all. Not sure what is correct... Everything I have read is that the throttle stop nut is only to keep the butterfly valve from closing all the way and sticking shut...

osv

is this with the motor hot or cold? or both?

when the motor is warmed up, i think that the aux air valve shouldn't be a factor, unless something is wrong... i assume this is a 22re? what i did with my '86 was degrease the inside of the tb, in front of the throttle plate, and put a big piece of tape over the passageway going to the aux air valve... it was a big enough piece of tape that i was able to wrap it around the outside of the tb, so that it wouldn't get sucked in.

if the problem goes away with the aux air valve taped over, you know that it's related to that.

ideally you should get rid of the aux air valve setup, do a plenum/tb swap from a later 22re, it's a much better warm-up system.

Terrys87

iTrader: (1)

I forgot about this upgrade and need to look into it again. Thanks!!!

osv

http://siestaoffroad.com/tbody.html

:-)

jennygirl

I swapped to the later model TB/plenum as well for the cold idle up improvement. I highly recommend it!

There is a link in my signature if you want a secondary reference, with more pictures.

Sounds like you could have a vacuum leak, though. That will cause it to idle higher and run rough (lean). Likely culprits start from the brake booster diaphragm, to a simple vac hose attached to the plenum or one of its connected assemblies.

Easiest way to find a vacuum leak is to take a propane torch (without lighting it of course!!) and go around all the vac hoses with it. Propane is not very dangerous and won't harm the motor one bit! If it idles up more when you are hovering over a certain area, you have found the leak.

Other option is to get a set of rubber vac line caps at the auto store, and cap off all of the connections on the plenum. Take a picture before capping everything so you don't forget the routing of all the vac hoses. You won't harm anything by having them all disconnected as long as all the holes capped on the plenum. I prefer this method, actually. I have deleted most of my vac lines anyway

Good luck! These idle issues are super common on this motor, it seems

EDIT: forgot to add. if you go the cap route, I would leave the PCV and breather hoses attached. It is safe to cap everything else. Still have to check for vac leaks on those, too.