GM IAC Control

chrispel · Post by **chrispel** » Tue Aug 15, 2006 7:39 am

Ok I have been trying to read all I can about how to control the GM style IAC. I have it all wired up right from what I can tell but all the changes I make to the idle steps table don't seam to change idle rpm. I had it all the way down to 0 and all the way up to 255 for the temp I was at without any luck of change the idle speed. I read some place that you need a H bridge circuit for this now does the MS2 V3.o have this built into the board or do I need to build it in the proto section and wire it in?

S.Bretz · Post by **S.Bretz** » Tue Aug 15, 2006 8:36 am

Chripsle...mine did work, WHen I had it. you just need to hook the circuit up right. I didn't use a bridge. There appeared to be a probelm with the older codes where after a minute or two the IAC would just stop working...thry the latest 2.3x code and see if that helps out.

BottleFed70 · Post by **BottleFed70** » Tue Aug 15, 2006 10:30 am

1st step is to remove the IAC and verify that it is moving.

chrispel · Post by **chrispel** » Tue Aug 15, 2006 12:28 pm

I'm running 2.6 something. If I remove it while the car is running it's going to rev up really hi. Is there a way to check to see if it's working without the car running?

S.Bretz · Post by **S.Bretz** » Tue Aug 15, 2006 4:24 pm

Get an extra one and just plug it in...have someone cycle the key and watch to see if the indle moves. I know those IAC's are a PITA to get out without removing the tbody, so try to find and extra.

chrispel · Post by **chrispel** » Tue Aug 15, 2006 4:46 pm

Yeah I think I might hit up the bone yard tomorrow. I'm running 2.685 code.

BottleFed70 · Post by **BottleFed70** » Tue Aug 15, 2006 9:53 pm

chrispel wrote:Yeah I think I might hit up the bone yard tomorrow. I'm running 2.685 code.

Let your car warm up(pintle should fully extend) then shut it off, remove IAC and turn on key(don't start). You should see the pintle retract.