Idle air control
- Thread starter wooooof
- Start date
Yes there is, but it's a little time consuming and involved, although not complicated. Since you have the scanmaster you'll be able to see your adjustments at work.
First, locate the minimum air bleed screw near the top of the throttle body on the driver's side. (Most people mistakenly think that screw is idle speed adjustment, it is NOT).
By making small adjustments to it, you can bring the IAC numbers in line with what you need. Turning it clockwise will cause the idle rpm to increase a bit, the computer will see this and decrease IAC value to bring rpm back to it's computer controlled value.
Try bringing it down in small incraments of about 10. Then you'll have to re-adjust the tps idle value. Moving back and forth between IAC and TPS to keep them both in proper adjustment as you go. Try not to get the IAC too much below 20. 15-30 are good values.
First, locate the minimum air bleed screw near the top of the throttle body on the driver's side. (Most people mistakenly think that screw is idle speed adjustment, it is NOT).
By making small adjustments to it, you can bring the IAC numbers in line with what you need. Turning it clockwise will cause the idle rpm to increase a bit, the computer will see this and decrease IAC value to bring rpm back to it's computer controlled value.
Try bringing it down in small incraments of about 10. Then you'll have to re-adjust the tps idle value. Moving back and forth between IAC and TPS to keep them both in proper adjustment as you go. Try not to get the IAC too much below 20. 15-30 are good values.
Usually none unless they're WAY too high, which might cause an off idle stumble. If his are 75 or so, but causing no issues, there's really no reason to change it.
On these cars, the old addage "if it aint broke don't fix it" goes a long way.
On these cars, the old addage "if it aint broke don't fix it" goes a long way.
Did a spring cleaning the last few weeks and finally was able to change the serpentine belt. My IAC was between 75 & 80. I am new to these cars but learning
at a rapid pace. Does someone have a picture of this screw? Hopefully with an arrow to it suggesting "Here it is dumbass". I just want to be sure so as my usually luck won't bite me on the ass. Thanks!
Mike
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- Joined
- May 27, 2010
Just take your head and smack it into the Throttle body a couple times you will feel a bump with a rubber cover on it remove said cover and WALLA!!! if there is no cover then wipe the blood off your forehead and you will see a screw attached.
GNONYX
Well-Known Member
- Joined
- Oct 16, 2009
This what I was looking for. I am very green when it comes to these cars. However, if you need help on a 1992 S-10 4 banger, I'm your guy!
Mike
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My rubber piece is painted gold. Is that how it came from GM? It looks to be in perfect condition.
Mike
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They were originally silver. They can take on a goldish tint with heat and age.
Thread hijack. I have the same problem and idle screw is backed out all the way, not even contacting the throttle bracket. My iac value is still around 80-90. My tps value was around .55 and I clocked it back to .44 with no change. I have a new iac on order but I think the problem is the ECM commanding the value, not the actual iac. Any suggestions?
X2, people get crazy over that no higher than 30 IAC count thing.
You screw it back IN to decrease the IAC number. Probably nothing wrong with your IAC valve. And again, it is not an idle screw it is the minimum air rate adjustment. Yes the ecm commands the value. Your's is high because your throttle plate is almost totally closed.
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GNONYX
Well-Known Member
- Joined
- Oct 16, 2009
I had this many years ago from one of our member, and have yet to see if it will reset the IAC back to base reading. You can give this a try and see if this will help you to lower the IAC count.
Post some results once you accomplish your adjustment of IAC and TPS
That is the correct procedure to set the minimum air rate and it does work. However opening the throttle plate causes the IAC to close not open. It should also be noted that the IAC and throttle body passages should be perfectly clean prior to doing the procedure. If the IAC circuit is dirty the IAC counts will be higher to compensate.
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My car when I turn it on will run fine, then sound like it is going to die, then catch back up with itself and repeats the process. I was assuming the IAC was causing this. There is that word.... Assume.
Mike
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Romove and clean your throttle body and follow the minimum air rate procedure above.
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I've nevet heard of the "reset" but it can't hurt to try it. The iac adjustment is right in the service manual and is the better procedure to follow. I don't think there is any "magic" number. The goal is to have a smooth idle and no stumble upon acceleration.
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