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06-29-2021, 07:29 PM
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#1 |
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Member
Join Date: Nov 2016
Posts: 206
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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?
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06-29-2021, 10:29 PM
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#2 |
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Member
Join Date: Mar 2003
Location: MA.
Posts: 288
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Re: Xfi 2.0 question on lt1
Adjust the throttle followers
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06-30-2021, 07:36 AM
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#3 |
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Senior Member
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Posts: 894
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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.
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Jeff Niceswanger 3740 SS Last edited by Jeff Niceswanger; 06-30-2021 at 04:30 PM. |
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07-01-2021, 09:02 PM
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#4 |
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Member
Join Date: Nov 2016
Posts: 206
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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.
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07-01-2021, 09:05 PM
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#5 |
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Member
Join Date: Nov 2016
Posts: 206
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Re: Xfi 2.0 question on lt1
It does it most all the time. Cold or warm. It’s a B-C/SA.
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07-01-2021, 09:07 PM
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#6 |
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Member
Join Date: Nov 2016
Posts: 206
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Re: Xfi 2.0 question on lt1
What is decay rate and what’s the proper way to adjust it.
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07-01-2021, 10:10 PM
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#7 |
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Senior Member
Join Date: Sep 2011
Posts: 769
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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.
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07-02-2021, 12:44 PM
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#8 |
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Junior Member
Join Date: Aug 2013
Location: Chatham, ON. Canada
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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.
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Pierce Jones 1995 Camaro D/S #3102 |
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07-02-2021, 12:56 PM
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#9 |
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Senior Member
Join Date: May 2020
Posts: 517
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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. |
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07-02-2021, 01:04 PM
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#10 | |
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Senior Member
Join Date: Sep 2011
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Re: Xfi 2.0 question on lt1
Quote:
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