Ok, long story short, THE IAC WILL NOT CLOSE COMPLETELY! arg... ideas? TunerCat here. 120 steps on the IAC startup, and 56ēC warm park position = 0.

Is there always the 120 steps? Something I'm missing here? How many steps are there, total?

Thanks!

 

Possible 255, *usually*.
Normaly, and I'm guessing here, the IAC goes thur a full range reset at key off, to *knock the big pieces of carbon* off the pintle.

 

I think I'm going to try this, and see where it ends up -

Do Diagnostic mode (flashing lights)
wait 30 seconds
disconnect IAC connector

Gonna see if it's completly closed.


What I'm trying to find out, is that if the 'Startup position' is considered like the 'zero' point.

Um.. how to explain... ok, say 120 is the startup position.

In the warm park table, a setting of '10' = 130 steps. a setting of '0' = 120 steps.

Possible?

 

Data logging is much slower then how fast the IAC can move, and be commanded to move.

From what I've been able to see in staring at the ecm bench with one of the gm codes:
At key off, the Iac is fully extended, and then retracted the 255 count.
At startup, as the engine is cranking the IAC extends from the 255 to the park position.
As the engine first runs, the Anti-stall will move the IAC to get to the commanded idle RPM/temp table's commanded speed.

Your going to have to use something other then the ALDL, IMO, to get to see the IAC's commands and movements.

Some of the old 3.8L cars, have a bolt on IAC housing, that's easy to look into, so see the IACs movement.

 

The V6's IAC bolts to a plate, that in turn, bolts to the throttle body. Seems I will be doing some experimenting tomorrow

 

Well, it looks like when you shut the car off, the IAC closes completely (goes to 0) then opens by a # of steps. I BELIEVE this is the 'IAC Startup Position'

I'm out playing with it right now. We'll see in a few