IAC goes to 310 and desired air hits 40g with LS2 TB using .0192 Scalar

[Mike04]

I have been fighting idle issues ever since I installed a LS2 TB. When I originally got the car back after an engine build, the ETC Scalar was set at .0330. That is incorrect for a 90mm TB so I adjusted it to .0192 and could never get the car to idle well and the IAC would go to 310 with desired air hitting 40 g/sec on a cold start. Once warm the count go down but was still above 150. After trying to adjust the tune off and on for weeks I gave up and put .0330 back in and got the car running pretty good and my counts where in the 70 range. After switching to a 2.5 bar MAP, I got back into the tune and couldn’t leave the wrong ETC scalar value in the tune anymore. It kept me up at night knowing it wasn’t right

I’ve reading a lot about IAC Step vs Effective area, thinking that might be the ticket I started messing with that. I’ve tried increasing and decreasing values here with no real progress. I’m kind of at a loss as to what to do next. I was hoping someone might have some insight why it would max IAC and desired air at start up.

Attached is my tune with the .0330 Scalar as reference. From this tune file I changed the scalar to .0192 and then messed with increasing the values IAC Step vs Effective area and then tried decreasing them. With this file and the .0192 I couldn't get the car to start without giving it gas and it would die when I let off.

[DSteck]

Your electronic throttle system doesn't use a IAC. You need to make changes to the base running airflow.

[Mike04]

I'm obviously confused... Is this because of the SD tune?

So, IAC Step vs Effective area is left stock, Scalar changed to 90mm TB, log new base airflow and add to tune (initially add some air to get it to run)?

[DSteck]

You can make the IAC chart whatever you want. It's not use. Your electronic throttle vehicle does not use an idle air control motor or system. It's all throttle controlled.

Yes, you need to log desired airflow.