Xfi 2.0 question on lt1
 

When I rap the throttle and the rpm goes up. It seems to take a long time for the rpm to get back to idle. When it does idle down It idles at 1200-1300 rpm. What can I do to make it go back to idle quicker?

Re: Xfi 2.0 question on lt1
 

Adjust the throttle followers

Re: Xfi 2.0 question on lt1
 

Like previously stated, if the car has an IAC ( Idle Air Control) on it you can adjust the throttle follower and try to help it. But an active IAC on a Superstock car is rare. I doubt you have one. Most of them are unplugged, blocked off, gutted or deactivated in the program. Its probably just a ill tuned map with the tune needing much more air than it should to idle, so the throttle body blades are opened way up, which in turn causes a sloppy return....
Make sure you don't have any type of vacuum leaks, especially at the map sensor or hose. Vacuum leaks play havoc with FI tunes...
You didn't mention whether is does this right after its been started, of after its warmed up and siting there running. If its right after a restart it is the After Start Enrichment and Decay rate,. Probably more so the Decay rate.

Re: Xfi 2.0 question on lt1
 

Anybody got a screenshot of a properly adjusted throttle follower? What is the proper way to adjust the throttle follower? Which way does what? Sorry to be so stupid.

Re: Xfi 2.0 question on lt1
 

It does it most all the time. Cold or warm. It’s a B-C/SA.

Re: Xfi 2.0 question on lt1
 

What is decay rate and what’s the proper way to adjust it.

Re: Xfi 2.0 question on lt1
 

It sounds like you are using the IAC. Disconnect that sumbish. You don't need it and should solve your problem to allow the throttle body to simply close to your set idle point.

Re: Xfi 2.0 question on lt1
 

I was having similar issue last year with Holley HP and IAC controlling. I tried tuning decay etc. I couldn't get it to work well.

Thanks to posts on this site I finally unplugged the IAC this year. Much better returning to idle along with better idle quality.

Re: Xfi 2.0 question on lt1
 

So... I'm a carb guy, know zip about FI...
What exactly is the IAC supposed to be doing?
Is that similar to the Idle control that was to up the idle when the A/C was on, back in the carburetor days?
Or something else.

Always curious about how things work.

Re: Xfi 2.0 question on lt1
 

That is it pretty much and why we can disconnect them.