IAC issues

For discussing injector selection,manifold modifications, throttle bodies, fuel supply system design and construction, and FIdle valves and IACs.
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64Vair
MegaSquirt Newbie
Posts: 10
Joined: Sat Jun 11, 2005 10:35 am
Location: Detroit Michigan Area
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IAC issues

Post by 64Vair »

I need some help setting up my IAC. I know I need to count the steps to open, but how do I do that? It is a GM IAC, and I have read others here that say theirs opens 160 or so steps.
Also, when I hook it up, seems no matter what I set the steps to, it jumps the engine to 2500 RPM. I have it set at 160 total steps right now, and it will return the engine to proper idle, then 2500 RPM. I shut it off, restart, and again, proper idle, then 2500 RPM. So I am guessing that 160 steps is right? Also, I have set it to open 50 or 25 steps for fast idle, and as mentioned, 2500 RPM. Any suggestions welcomed, I know this is something simple and easy. I only want IAC on until around 100 or 115 degrees, (air cooled motor, warms up FAST!).
Thanks!
Tom
RIT Rocks, Cancer Sucks!
dave.a.cote
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Posts: 3
Joined: Sun Feb 24, 2008 7:48 am
Location: Saskatoon, SK

Re: IAC issues

Post by dave.a.cote »

I am also having IAC issues. Mine seems to be inconsistent from time to time - like it looses it's zero position. It is a Dodge IAC but it looks identical to the bolt-on style GM IAC in the manual. If I close my IAC entirely the engine will basically not run - not enough air - if I set it to idle at say ~900 RPM one day, the next day at the same coolant temperature, the IAC will allow enough air to idle the engine at 2000 RPM - definitely no good for an automatic transmission! Has anyone else seen this kind of problem?

How long after you start your engine does it take to ramp up to 2500 RPM? Change one of your gauges to IAC position in megatune - what does it read when your engine is idling properly and what does it read when your engine is idling at 2500 rpm?

Dave
64Vair
MegaSquirt Newbie
Posts: 10
Joined: Sat Jun 11, 2005 10:35 am
Location: Detroit Michigan Area
Contact:

Re: IAC issues

Post by 64Vair »

I have been thinking about my issue, and I have to wonder if the IAC is wired backward. When it is hooked up, and I start the car, it idles at normal speed, then after a few seconds, maybe 5 or so, it jumps up to speed. Also, if I have the IAC out, and hooked up, when I turn the key on, it shoots the pintle out! I will have to try your suggestions. I just have not had time to mess with it. I want it to be completely off by 125 degrees or so. At that, it will never be in use for more than 5 minutes of running. Air cooled motors warm up FAST.
Thanks for your suggestions, will give them a shot when I have some time.
Tom
RIT Rocks, Cancer Sucks!
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