Tried to adjust (what I thought was) the IAC. Unplugged the IAC plug, and tried to adjust the torx screw to lower the idle from the new 1800 RPM to 550 RPM. No matter what i did no difference at all, one time it went to 2200 though. Then i npticed that it was connected to the throttle adjust screw, so was i turning the right thing? this pic shows the location of the screw i was messing with. (in red).

 

TTT

 

You can't adjust the IAC, that stands for Idle Air Control, it's a stepper motor. You're trying to adjust the idle. There's a procedure for this in the thirdgen.org tech section. How did you get the idle to 1800 in the first place?

 

You keep saying two diff. things!

You and the tech article say that you can adjust "minimum air" or in other words idle. And i followed the (not really complete) steps on how to do it! Now if you cant adjust it why is there a billion threads under search for IAC minumum air adjust? All I want is two adjust this, no ttt or anything else (I assume Tisk,tisk,tisk).

Pick a mouth side and stay with it.

(yes im frustrated!)

 

actually ttt mean take to top i think, so other peopel can get you an answer.

and i think that is the torx i used to adjust my idle with, it's right near the TB. mine is painted yellow in this pic...


<img src="ftp://nfimports:pics@142.163.97.139:9600/Picture%20234.jpg">

 

I always thought it meant To The Top

 

I always thought it meant To The Top

 

I'm not saying two different things. Again, IAC stands for Idle Air Control. But there's no such thing as IAC by itself, it describes a type of motor. So put them together, and you get "IAC Motor". You can't adjust anything about it. You can reset it, sure. You can replace it, and you can clean it. But unless you bust that case open with a dremel and start rewiring the motor, you can't adjust it! Even then, I doubt you'd get that little motor back together, and you'd be paying $60 for one. The IAC motor has a 4 pin connector coming out of the back. 85-89 IAC's screw into the TB like a spark plug. 90-92's use retaining screws.

That being said, adjusting the idle is possible. Adjusting the IAC isn't. You're make things harder than they are, man! If it looks right, have a go at it. What part of the procedure wasn't clear? Have you bought a manual for your car yet? The Haynes 82-92 Firebird manual shows clear pictures of the throttle body, if I recall correctly (IIRC).

You're finding tons of messages that mention IAC and adjust and minimum and air, but not necessarily related. And people re-set the IAC, which allows them to set minimum air.

And yes, TTT is To The Top. BTT is Back To Top. IIRC is If I Recall Correctly. IMHO is In My Humble Opinion. Did I miss any?

 

to adjust the idle you just turn that torx screw on the back of the tb.,it pushes out the throttle linkage and all it does is open and close the throttle body a little bit to let in more or less air, tahts how u adjust ur idle. its pretty simple

 

I know what a 2.8 looks like, lets se a better shot of that dynomax.

 

First, let me make one thing perfectly clear. You can ONLY adjust the Idle Speed through the eprom. PERIOD.

Adjusting the "minimum air screw" is to resolve driveability issues when either your IAC count is too high or too low to maintain a stable idle. If it "hunts" (idle speed rises and falls), that is a good reason to adjust the "minimum air" via the torx. If you were to hook a scan tool in a "unstable idle" situation, you'd see either the IAC counts are very low (near 0) or very high (near 160).

You normally adjust the idle speed (via the torx) to match the "normal operating idle speed" of the engine. Typically it's around 600 rpm. If you modify your engine and raise your idle speed to say 750 rpm (within the eprom), then you should set the "minimum air screw" to correspond to the 750 rpm.

But DO NOT adjust the torx screw if you are trying to adjust the Idle Speed of the engine. You can only do that in the eprom. THEN you may need to adjust the screw (so the IAC counts are not too high or too low). But adjust the screw by itself (to raise the idle speed) will cause driveability problems (much like you are experiencing).