[Gmecm] $8D IAC stalls engine on decel

[David Allen]

> Good point... I haven't set mine... but shouldn't then all the IAC settings be 
> too high after setting the min idle with the throttlebody? 

  Nope.  You want the ECM to be able to add supplimental air to the engine to overcome cold operation and added load such as the A/C but there is no need for the ECM to have the capability to lower idle speed below spec.
  There are several schools of thought as to min airflow setting technique.  The one that works for me is......

Set the idle speed high at minimum airflow screw; then turn off engine and want for ECM to power off. 
Connect ALDL program.
Then re-start and allow engine to be FULLY warmed up.  
Now lower minimum airflow until you see 4 or 5 IAC counts on the scan data.

The reason to start high and then lower the min airflow setting, is to prevent the ECM's IAC throttle-follower function from defeating you.

What kind of throttle body are you using?  The original Bosch one?

>> Have you a VSS input?  
> Nope, and that was one of the problems I was thinking about.
> Tried to follow the IAC code from the ANHT hac, but couldn't figure exactly 
> why with a VSS=0, the throttle follower keeps getting down to 0 anyway.
> BLM cells don't want to change because of lack of VSS too :(
> So I'm still trying to figure out how to get a VSS installed.
> My problem is where to install a VSS ... and what kind of VSS sensor to use.

What kind of VSS did the Bimmer have from the factory?  If any?  Even if it had one dedicated to the Cruise (or 'tempomat' IIRC) you might be able to adapt this to your system using a divider or buffer of some sort.

I have run without a VSS with no stalling issues.  Really it is not necessary; but it is nice to have! My EFI Boat has no VSS (BSS?) and it never stalls.

Glad your project car is working well!
David