IAC Count at 130

[qwic87gn]

I can't get my IAC count down to the target value. The set screw is backed out to where it's not even making contact. Has anyone experianced this? Is there a adjustment in the linkage to remedy this?

 

[Just a Six??]

I have had problems with mine that are not typical & I learned a lot about the IAC from them. Like that the ECM has a separate driver for it? Many other things. The thread is on TBS under my name if you seach a few months back. Mine works fine until I put it in park & still pegs to Max everytime but doesnt affect anything for me so I havent gone further with repairs to it yet. Probably in the column or the switches mentioned in the threads.

 

[turbo39151]

Did you rest the ecu? There are numerous "ways" to try and fix the issue. I tried them all. Best advice is to borrow a known working unit from a fellow TR friend and see what happens. Likely that the unit is bad. I had to replace two on two different cars at the same time! When I installed the new one, it worked perfect and I did not have to touch anything.

 

[Eric Stage I]

You are going the wrong way. If the screw is not touching, then the throttle blade is completely closed, and the IAC has to max out to get enough air to idle. You need to open the throttle blade to get the IAC's down.

 

[qwic87gn]

You are going the wrong way. If the screw is not touching, then the throttle blade is completely closed, and the IAC has to max out to get enough air to idle. You need to open the throttle blade to get the IAC's down.

Idle is 850-900rpm with the screw not touching. If I open the blade, the counts go higher, not lower. It's doing the exact opposite as it "should".

 

[Eric Stage I]

Make sure the idle TPS volts don't go above .48v during the process of adjustment.

 

[87NAT]

When looking at the TB from the drivers side you should see only about 1 1/2 threads of the screw sticking out . This is a good ballpark setting to get started with.

 

[Dwayne]

I have never been able to get me iac counts below 50. It doesn't matter where the adjusting screw is, I've used several different iac's and 3 different ecms. I do know that my throttle plate to bore clearance is much tighter than stock............could this be a contributing factor ?........also I have no vac. leaks.

 

[GNRick]

Mine came down after spraying the inside of the throttle body with carb cleaner.

 

[turbojimmy]

Make sure the idle TPS volts don't go above .48v during the process of adjustment.

What he said.

You have to watch both the IAC counts and the TPS voltage when you're goofing around with the set screw. If the TPS voltage goes to high, the ECM will think you're no longer at idle.

I just put a 70mm Accufab TB on my car and despite having to start from scratch with the TPS, IAC and set screw settings, it only took about 10 minutes of playing around with it to get it right. Just watch both values (IAC and TPS).

Jim

 

[83ttypecooled]

Hi,
Minimum authority (that's what Buick calls it) idle adjustment is pretty critical, so you need to set that before proceeding. They have a cap on the screw for a reason. It sounds to me like your IAC is out to lunch.Also, verify TPS setting after your readjustment of base idle.Good luck with your troubles...