Throttle body wheezing

[Craig 94 TA GT]

I'm not sure how to describe the sound, but every so often, I notice the new 58mm AS&M making a wheezing sound that resembles a high pressure sink turning on. It only does this once in a while...mainly after a cold start, or after a running on the freeway for a while, then hitting a stop light. The sound lasts for a few seconds. I'm thought this has something to do with the IAC.

So recently, I scanned the PCM and noticed that I had split BLMs at cell 16: 160/128. IAC counts were around 20. So I tried adjusting the stop screw on the TB because I heard that this can affect cell 16 BLMs. I adjusted the IAC up to 40-50, and BLMs at cell 16 went to 155/135. So it's now a smaller split. However, this "wheezing" noise is now much more frequent. It can happen during any time when driving or starting. I'm not sure why the IAC seems to be affecting this noise...does anyone have any experience with this and bigger TBs?

Thanks in advance.

[BDM Camaro 95]

Has your intake manifold been ported to match the 58mm throttle body?

[Craig 94 TA GT]

Yes, it has been ported to match the bigger holes.

[Injuneer]

Check the IAC passage for casting flash or dirt. The BBK TB's are known for a "whistle" that comes from a poorly finished IAC passage. Maybe there's something in the AS&M.

[Craig 94 TA GT]

Thanks Fred, I will check the passage out. I wonder if this will also help my cell 16 BLM split, or not.

I also noticed that someone claims that the AS&M TB has an issue. Here's his description: "OK, now for the aftermarket throttle bodies. My AS&M 58mm throttle body had a major "short circuit" between the IAC outlet and the main plenum as shown in the pic below left. Even if I close the throttle blades completely, this will allow idle air into the main plenum. What to do?"

http://para.noid.org/~lj/PCM%20Tutor...litBLMinfo.htm

Is putting this tubing necessary? I don't see why the original design is an issue, but I don't know if it's beneficial to perform this "fix".

[Injuneer]

I'm not sure how valid that concern is. Everyone says they have problems with the Holley 58mm TB providing the correct IAC air, but I never had a problem.

[Craig 94 TA GT]

When I was inspecting the throttle body (about 2 minutes after being run for 1 minute), I pulled the butterflies up to look inside. I noticed that there was a smoke-like vapor that smelled like gas - probably gas vapors. It kept coming out of the intake manifold. What is this from? I don't ever recall this on the stock motor, but I don't know if I ever opened the butterflies and looked inside after a minute of running.

I at least had a chance to inspect the IAC passage and it looked OK.