Bluefire

How clutch operation effects Idle airflow on a 2003 C5 Manual with respect to the Throttle Crack/Follower Airflow adders.

This is how I believe it works:

1. Throttle closed, rolling, clutch released.
a. Cracker airflow table is used when Vehicle speed is > Cracker Enable Speed.
b. Cracker airflow is used in-off throttle coasting down to Desired Idle RPM value. (Follower airflow adder is only used for on-throttle adjustments).
c. Vehicle speed is < Cracker Disable Speed, Cracker airflow is disabled and Adaptive Throttle table is used.

2. Throttle closed, rolling, clutch engaged (Neutral for A4).
a. When clutch is depressed (Neutral for A4), the Cracker Airflow adder is disabled, and the Rolling Idle Airflow table is used as the engine RPM drops down to the Rolling Idle RPM value.

Does it make sense? Am I close?

Thanks

Bluefire

Wow. 30 views and... nada,

tblu92

Ok I went to the EFILIVE training school and was taught the only time you need an adjustment to the cracker tables is if you inatall a larger than stock T Body
otherwise increased airflow or major mods are best tuned using the FOLLOWER tables
Also why do you think you need an adjustment in the 1st place ? Typically these adjustments are used to correct both in gear and P/N off idle deceleration where your engine wants to try and die or it has a hanging idle----What are your symptoms ? mostly these corrections are only needed with large cams---

Bluefire

I needed to adjust these because I just did a rebuild.

Fast 92mm intake
LS2 90mm MAF
Comp Cam 231/242 .617/593 112 (14° overlap)
Haltech CAI

It runs great, and idles well. It would surge and die only when clutch was engaged. I found out that the TC and TF tables are disabled when clutch is engaged. When I understood that the Rolling idle table was use when clutch was engaged, I set the Rolling Idle RPM and Airflow. Now my car behaves as it should.
My original post was just looking for validation on how I thought the clutch function worked.

BTW, I did need to decrease the Cracker airflow because there was a slight idle hang on off-throttle decelerations.

tblu92

Normally we fix idle surging with the "desired airflow table" try like adding 20% to that whole tbale if ypu are still getting surging------Also have you adjusted ypur fuel trims ? or have you disabled them ? Often with that may mods it's best to disable them If not try and get all your P/T fuel trims to read slightly negative or "0" ( the large MAF and T-Body often skews the trims) and can be troublesome to fine tune