GM IAC Control

For discussing injector selection, manifold modifications, throttle bodies, fuel supply system design and construction, and FIdle valves and IACs.
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chrispel
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GM IAC Control

Post by chrispel »

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?
MS2 V3.0

92 Saturn SC2 Vortech V1 A Trim
98 Saturn SC2 DP Nitrous
S.Bretz
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Post by S.Bretz »

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
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Post by BottleFed70 »

1st step is to remove the IAC and verify that it is moving.
1970 Ford Mustang
MSII, v3.0 PCB, v2.36 firmware, Megatune 2.25
chrispel
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Joined: Sat Mar 19, 2005 8:37 am
Location: Buffalo

Post by chrispel »

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?
MS2 V3.0

92 Saturn SC2 Vortech V1 A Trim
98 Saturn SC2 DP Nitrous
S.Bretz
Helpful Squirter
Posts: 88
Joined: Fri Nov 18, 2005 8:18 pm

Post by S.Bretz »

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
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Joined: Sat Mar 19, 2005 8:37 am
Location: Buffalo

Post by chrispel »

Yeah I think I might hit up the bone yard tomorrow. I'm running 2.685 code.
MS2 V3.0

92 Saturn SC2 Vortech V1 A Trim
98 Saturn SC2 DP Nitrous
BottleFed70
Helpful Squirter
Posts: 91
Joined: Fri Jun 24, 2005 2:22 pm

Post by BottleFed70 »

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.
1970 Ford Mustang
MSII, v3.0 PCB, v2.36 firmware, Megatune 2.25
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