I'm working with a 7747. I dug thru the archives and found a bunch of neat stuff. Which brought up a question I've always had.

If I raise the throttle follower what effect will it have on the IAC. It seems to me that if I raise the throttle follower the IAC doesn't move as much. BUT I've noticed that the coolant temp has alot to do with the IAC position (at a cruise 40 kPa, 2000 rpm, 70 mph). Since we always get crazy weather here it's hard to tell what's going on.

Also, can someone tell me how the TF and AE tie into each other? Generally, do you run alot of AE with little TF...or what?

 

And folks wonder why I keep menioning an ECM bench...
It doesn't care about the weather.

 

I know the IAC doesn't care about the weather. I know the IAC doesn different things according to engine temp. That's what I meant. Or am I mistaken?

I know why you keep mentioning the ECM bench, given my current financial position it's not something I can budget for. Maybe you could enlighten me since I have no ECM bench at the moment.

 

V8,

This is exactly the exercise I have been finalizing. The more TF you have the more air bleeds past the butterflies. Originally, the idea was to allow increased airflow through TB's that were a bit on the small side. However, if the TB's have been increased in size, then you should be trying to keep air velocity through the venturis' as high as possible. By minimizing the throttle follower, more air runs through the venturis and less bleeds past it through the IAC opening.
And I have found that by limiting the TF, you run less AE although you need to watch the %MAP transitions.

 

Hey, an answer! Thanks Dom!