With the stock throttle body, IAC were fairly consistant at around 50-70.
I bolted on a borrowed 58mm TB that has a sinlge small hole drilled in each blade and now the IAC counts are around 15 in Park (A4) and anywhere from 80 to the max 160 in gear at a stop...one stop sign they are 80..the next they max out at 160. Idle speed is set to 800rpms.
If I open the TB any with the set screw, the idle in Park goes sky high sometimes..not all the time and the IAC steps will be 0 so it can't control idle.
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I have a rough idling 236/242 114LSA cam.

I'm wondering why the IAC counts are so different in gear from one stop to the next....it did not do this with the stocker?
Also, why would a hole need to be drilled in the blades, I think that may have something to do with it, not sure.
Should I even be worried about the IAC steps going so high? Doesn't seem to make a difference, of my GN if its higher than 50 there's a terrible tip in stumble.

 

Problem is the TB was modified in the wrong fashion, should have recreated the IAC bypass hole found in the center of a stock TB that way the idle air uses the IAC distribution circuit rather than the plenum like it does with the drilled blades.

 

You should NOT be using the "idle screw" to hold the blades open atall.
Here is a link, not all TBs will need the "plug" he had to make but the drilling the hole applies to all the aftermarket LT1 TBs I know of.
http://members.***.net/chipsbyal/page/idle/index.html

 

switch back ,cuz it aint goin away,just curious if its a 3.8 what do u mean each blade?your eventually gonna burn ur iac out and i hope u got a c-note to cover it.just sayin what i see.

 

Makes perfect sense...why in the heck are the aftermarket TB made that way??

 

Gotta make that alum. for it to "seat" and "seal" against the intake. Otherwise, the IAC circuit will bleed thru into the throttle portion

 

Drilling the holes in a Tb is a poor mans tune and isnt the correct way of doing things.

Getting a car tuned correctly will fix your iac issues. Now you might find out that your holes that you drilled will cause a high idle code and cause a cruise control effect where the car will idle high for no reason.

Those were all the problems i was going through when a local tuner drilled the holes in my holley 58mm tb for my 847 cam. when i got the car it was running like crap and couldn't figure out why until i took off the intake elbow to do some cleaning... So got the car retuned and covered the holes and now the car runs perfect no "cruise control" effect, no check engine light no high idle... but i defently got a $400 dollar tb with 2 holes because someone was too lazy to tune my car correctly.

 

Yep, I can sometimes cruise at 35 mph without ever hitting the pedal after I get up to that speed.
From everything else above and the links, sounds like a 11/64 hole may be required if there are high IAC counts only in the IAC passage like the stocker has, but definitely not in the throttle blades as everything you descibe and others are the symptoms I'm having.
It was a borrowed TB, I did not drill the holes, so I'm returning it.

 

If you did things yourself rather than relying on others you would understand what we were talking about, it is clear at this point you do not. We are talking about duplicating something the stock TB has aftermarket ones do not. You are talking about holeS which tells me you had guys drilling the blades which is what I came in here saying was wrong. Go back and actually READ and look at the link.

 

My Holley 58mm idles fine with no holes drilled anywhere. Also borrowed a BBK 58mm when I was doing some work on the Holley, and that idled fine as well.

 

Maybe yours is like mine. Check out my pics a few posts down here:

http://web.camaross.com/forums/showthread.php?t=471969

Maybe some of the old Holleys didnt have that hole, but mine does. Makes perfect sense to have it though (to actually make the IAC work), so if you have idle problems and no hole, drill it

The hole in mine is pretty large as well. Larger than the OD of a pen, but just smaller than my pinky finger

 

first off i would like to apoligize for misunderstanding the post.

Second... I do most if not all the work on my vehicle.... unfortunally there is things in the world where people don't have the knowledge or acess to do, I didn't authorize anyone to drill holes in my tb while they were tuning my car but they took it upon themselves to do such a silly *** thing "because every car with a large camshaft needs holes in the tb to run correctly".

And before you go making comments to me like this
I would advise you to STFU Because you know nothing about me or what i do!!

 

Fred, didn't I see another post where you had to modify the Holley to get it to perform correctly and for the blades to return correctly when letting off the throttle??
Did Holley fix these issues since then?

 

I have no idea what Holley has done in the 6 years since I bought my 58mm TB. I've seen people complaining about the blades not closing all the way, and I recently told someone how to use the spring adjustment holes that Holley provides, but I have no way of knowing whether those people had new or old units.

 

Does yours look anyhting like the one in the pics in this thread?
Someone said that it appears to be a newer design
http://web.camaross.com/forums/showthread.php?t=471969