2G IAC and Throttle Body Questions

[wishihadatalon]

Hey guys, I am trying to figure out a high idle situation on my wife's car right now. It has a modified BBK dsm throttle body (modified to take dsm shaft seals so no leaks) and megasquirt ems (so no stock ecu thinking here please).

Anyway, I have the FIAV blocked off on the car. I use the megasquirt ems to run the IAC for fast idle duty. I however do not use the megasquirt to control the idle after the car is warmed up. This is where I am having my issue. The car will not idle below 1,300 rpms. Today I pulled off the throttle body elbow to see if the small hole in the BBK throttle body was letting too much air by but what I found was that air was being pulled through the IAC hole. I was able to control the idle if I put my fingers over the holes. After looking at pictures online, the holes in the BBK body are the same size as the stock body so I know that isn't the issue.

So my question is how does the stock IAC work exactly. If its not being used does it seal off the passage to limit the amount of air the engine will see?

Thanks in advance for any help that you can provide.

 

[CleverDSMusername]

vacuum leak maybe? use berryman's b-12 card/choke cleaner & spray ALL vacuum lines, around the TB, around your intake manifold, if it picks up idle in a certain spot then spray in small increments in that area. i used this trick a lot in my 4 yrs of working on cars & helps out a great deal if you dont have access to a smoke machine like the dealers use.