[Gmecm] Closed loop and stalls

[Jay Vessels]

Hi there!

> 3 - Erratic idle can also be caused by a gummed up IAC. Pull it, check
> the pintle, and make sure the seat is clean and in good shape. 

Sounds like my old '84 Cavalier convertible :)

Darn thing idled at about 2k (making shifting from Park to Reverse 
fun!), nothing obvious wrong (i.e. timing, vacuum leaks, etc.) and 
nothing I did seemed to help.  I finally pulled the IAC out, grabbed the 
pintle, and yanked.  It came out -- whoops! -- but you can rethread them 
in, so I *gently* reinstalled the IAC with the pintle fully extended. 
Started the car, and it idled fine.  The IAC was sticky, and had 
retracted to the point that it couldn't extend itself.  All it needed 
was a little help.  I'm not saying that's the best method for working on 
an IAC but if your next step is buying a new one, it's worth a shot.

On some ECMs/cals (i.e. '747) the IAC extends itself completely when A&B 
on the ALDL are jumpered.  Not always true, but for some it works.  You 
can hear the IAC rattling at key on when it's trying to seat itself. 
Give it about 30 seconds, key off, remove the jumper, and start it up. 
Also, on some cals you can unplug the IAC once it has seated itself, 
start the engine, and set minimum air (throttle stop), and TPS idle 
voltage.  This is one of those times where it's handy to have the Helm 
manual that most closely matches your setup since it will talk about how 
to set minimum air, if it's possible.

Jay Vessels
1982 Chevrolet S-10 Sport, 2.8V6 TBI
1984 Chevrolet S-10 Blazer Sport, 2.8V6 carb. (for now)