Hey I have reset the iac a couple of times the exact way it says here.When i goto unplug the iac I can here it clicking or vibrating.Everything is clean i even took the pintle out and lubed it up,When i plug the iac back in and restart it still says 0 counts on the scanner.Learned iac is 40,while im driving around on and off the gas the iac counts go up and down but at idle in park or drive it still says 0.Does this mean it probably is no good?My rpms in gear are 650-750 in park 850(approx)It stays idling but i want everything to be working correctly!Thanx

 

I would say your as good as it gets. Having the IAC open is like having a controled vacuum leak. If you can idle fine with it completely closed that's great.

 

Ok,I thought it was supposed to be open or have some counts.I am not really sure what everything does for what yet.This is the first TPI engine I have messed around with,but thanx!

 

ideally you should be idling at 30-60 counts. This gives it enough room for a "fudge factor" if necessary. Your car's idle should change with various operating parameters (such as coolant temp and A/C request) and if you're idling at 0 counts, you don't give the car the opportunity to lower the idle speed when it calls for it.

 

Ok so any ideas how I could move it around if i turn the min air screw in more it will make the idle go up will the iac bring it back down???

 

Yes, assuming you don't have a vacuum leak...i/e the IAC could be giong to "0" because ,

a) the throttle blades are too far open and it's trying to slow the idle speed down..
or

b) you have a vacuum leak and the IAC is trying to compensate.

The "clicking" though, is a concern, mine never clicked when reset it, not sure abut others...

 

What you want to do is back out the minimum air adjustment screw on the throttle body. This will cause the IAC to open, thus increasing the counts, in order to maintain the commanded idle speed.

Turn the minimum idle screw counter clockwise. This will close the throttle blades and open the IAC.

I recently had to do a lot of adjusting to mine when I installed a new 52MM TB. I ended up with 59 counts. Anything lower and the engine would not idle down when I took my foot off the accelerator at roadway speeds.

Each modified setup is a little different though, so you just have to find the sweet spot for your combo through trial and error.

Jake

 

ok checked it out with a scanner on it and with key on not running iac says 160 counts then start it and at idle it counts down to 0 idle is right around 750 in park.When its cold first starting it wont even idle without some help from gas pedal.
Any more ideas??????????

 

Did you set your minimum air already? I think you said you did. How about trying to close your throttle stop screw a turn or so to force the IAC to work. That might not work, just a thought.

I suppose from the sound of it, your IAC is not working correctly. I only guess this because you just said that it won't idle when cold.

 

i have set everything just like they are supposed to be by the directions on this site.It wont idle when cold at all i have to give it gas.no vacuum leaks gauge reads steady at 16"everything is new except for tps and iac.
thanks

 

Pay no attention to the IAC counts with the ignition key to the "On" position and engine not running. It's not part of the procedure to set minimum idle speed.

What you're looking for are the counts with the engine idling; in gear (auto) is the best I've found.

If your system is showing zero counts, yet the engine idles at 750, your throttle blades are open too far ; the IAC is completely closed. This is not what you want.

If you close them a little - by turning the adjustment screw counter-clockwise, the IAC counts will begin to rise.

There is a step by step procedure for setting minimum idle speed. I'm sure it's posted here; I know it's on the CorvetteForum in the TechTips section and it's in most of the GM
service books.

If you need me to type it out I will; let me know.

Jake

 

Suggest you look for a vacuum leak, assume your ngine is stock? 16in/hg is a few in/hg too low, indicating a vacuum leak.

If you don't find a vacuum leak, suggest you get a full gasket kit for the TB (about 10 bucks) take it all apart and clean it and all passages.

No reason with a stock engine to adjust minimum air, assuming it was correct (and most likley was) when it left the factory...also assuming noone monkeyed with it before.

 

I thought if the vacuum gauge was steady that would show no leaks?I replaced every gasket from the manifold up twice!After driving for a while the idle has smoothed out but when cold it wont stay running and when changing gears like into drive or reverse it wants to stall only sometimes catching itself?Any more ideas im thinking of just replacing the iac????

 

When you replaced the pintel did you make sure it was not extended more than 28mm?

You can remove the IAC, connect it to the harness connector and turn on the ignition key. It should move.

Best to have it in your hand when you do this because when I did mine that way, the pintel extended all the way and actually came out of the IAC body and fell on the floor.

Vibrating shows you the little motor is working.

Jake

 

When you replaced the pintel did you make sure it was not extended more than 28mm?

Vibrating means the little motor is working.

You can energize the pintel with it removed from the TB and connected to the wiring harness. Hold it in your hand so the pintel won't extend all the way and come completely out and fall on the floor as mine did.

Jake