Hey gang - 88 TPI. I have been dealing with a minor rough idle from time to time and was told to suspect the IAC. I would like to clean it and have three questions:

a) Finding it - see attached pic. Have I drawn the arrows correctly? Is that the IAC?

b) Cleaning it - I've read various posts and have no plans on taking this apart (worried I will ruin it). I just want to remove it from the housing and clean the area I can get to without messing up / modifying the pin / spring. I plan on using throttle body cleaner and just wondered if anyone has any pointers for cleaning this correctly without screwing things up.

c) installing - I've read the torque should be about 13FT LBS, correct? And what I'm confused about is the computer re-learning process. I recall seeing somewhere on the forum that because my car is pre-90, I don't have to do anything manually to reset the computer / relearn idle. The car will do it by itself after a few drives. Do I have this correct? Can I just install it and let the car do the rest on its own? Or do I need to perform a manually reset with the A/B pin sequence stuff i've seen.

Thanks everyone.

 

You've got it labeled correctly. Once you unscrew it from the throttle body, you'll see that it's basically just a pin and spring. Take the whole throttle body off the car and clean it out too.

I used carb cleaner to spray everything off. An amazing amount of black gunk came out of mine. Much more than I expected. After waiting an hour for everything to dry, I simply screwed the spring and pin back into the IAC plastic holder and put the whole thing back into the throttle body. I didn't use a torque spec as the plastic seems to stop when it's in all the way.

Turn the ignition to RUN and wait about 5 seconds. You'll hear it go "plunk." At that point, it's been reset to the proper position. Start up the car and away you go.

The A/B pin under the dash is for changing your min idle RPM settings. That's optional. Vader has a good writeup about halfway down the page.

https://www.thirdgen.org/forums/tpi/...hen-going.html

 

Thank you for the detailed response Reid. Last night I removed the IAC and throttle body as you suggested. It was definitey in need of a cleaning.


I started it up after reinstalling it, and initially it seemed like the car was still having the minor rough idle. I took it for a ride and it drove fine (as usual). When I came back, I turned the car off...let it sit for a moment, and re-started it. usually doing this would cause an even more noticable idling issue. But this time is idled amazing.

I have much more test driving I want to do, but hopefully this at least helped the issue somewhat. THANK YOU!

Side note...Not so much on the throttle body, but the big silver piece it attached to (plenum??) was absolutely disgusting. I reached what I could but I could still see a bunch of blackness I just couldn't get to. Perhaps one day I'll try cleaning that, but I don't think that's the cause of my idle issue. Can't imagine what the rest of the engine looks like.