big cam idle *almost* fixed; coastdown rpm hang?

[flubyux2]

I think my idle is maybe 80-90% there using the walkthrough that has been discussed in another thread. I had to reduce the Final Idle airflow alot from what it was. It had alot of correction from over/underspeed. the adaptive idle spark was fluctuating wildly when i first got the car so i disabled it and began adjusting. i finally got the car to idle with ac on and require no spark correction at my target rpm. it keeps trying to idle high and im seeing a few degrees of spark retard to drop from 1000rpm. but im still getting 1100-1200rpm when coasting to a stop and it takes a while for it to drop below 1000rpm. my Throttle Follower Torque table has large negative values to try to trim down the last bit. Not sure if i should keep going further negative or if there is a better table to fix my coast down rpm hang.

LS7, big cam (idk which one), heads, intake, LT's.

Log and tune attached. stock file attached for comparison if necessary.

[07GTS]

if u have done double stoich u have to halve the IVT terms to correct fueling, if ur min airflow has number lower in 1200 then 800 its not going to want to lower past the 1200 as its odd to have a dip like that airflow dosnt follow that trend, u can try the integral airflow limits the coastdown halve those values see if it helps, ive had that rolling idle hang in mine and was playing around for ages with it but never got to a fix as i found a crack in the blower snout so it may have been allowing more air in and since im getting engine built so was never able to see if it fixed it or not

[c4z]

Your airflows tables look way high and don't really follow the stock curves. I would go back to your stock airflow values and see if that works, and slowly add .5 grams at a time to the entire table until your airflow stabilizes, but more than likely stock will work with your new base idle spark tables.

Also, it looks like you've removed the coast down drive adaptives ability to pull spark, at least set that back to stock so the ecu can pull timing to lower rpms even if the airflow is a little high.

I think my idle is maybe 80-90% there using the walkthrough that has been discussed in another thread. I had to reduce the Final Idle airflow alot from what it was. It had alot of correction from over/underspeed. the adaptive idle spark was fluctuating wildly when i first got the car so i disabled it and began adjusting. i finally got the car to idle with ac on and require no spark correction at my target rpm. it keeps trying to idle high and im seeing a few degrees of spark retard to drop from 1000rpm. but im still getting 1100-1200rpm when coasting to a stop and it takes a while for it to drop below 1000rpm. my Throttle Follower Torque table has large negative values to try to trim down the last bit. Not sure if i should keep going further negative or if there is a better table to fix my coast down rpm hang.

LS7, big cam (idk which one), heads, intake, LT's.

Log and tune attached. stock file attached for comparison if necessary.

[lukearmstrong1990]

can cheat and set adaptive idle to be active from 60mph and it will fix it

sounds like too much air as it hangs above targeted rpm with little timing. vac leak or too much base running air