greenvortec97

iTrader: (1)

Fbody A4 car with h/c/i

Car idles perfect, nearly got the whole RAF dialed in with the idle config histogram (It doesn't get cold enough in TX to dial in the far left)
drives perfect, Races Perfect. The only problem i have is the (ughhhh....ughhhhhh....) the RPMs do coming to a stop. It doesn't do it as bad when the car is warmed up but when its cold it does it horribly. I do not know what could be causing it. Im running SD enhanced OS as well.. I've made a few changes in real time tuning seeing if it would help (underspeed/overspeed/throttle follower/throttle cracker) It just pisses me off how great i've gotten the car to perform but I can't dial in that coasting idle or coming to a stop etc. I'll post a copy of my tune and see what you guys think.. I'm looking to learn how to do this on my own.. Not just a "here, try this" I wanna know why the car is doing this and what i should do to fix it..

ctd

iTrader: (1)

Well then a log of what is going on would really help.

greenvortec97

iTrader: (1)

I can get one asap, is there any specific parameters I should be logging that would help?

aknovaman

iTrader: (7)

Throttle follower and decay tables need adjusted among a few other minor tweaks.

greenvortec97

iTrader: (1)

i did a few changes and the problem is less now. Still does it though. heres a log from today when i went to meet someone

ignore the Wideband in the scan, I screwed up my inputs when i made a seperate config for my NGK wideband (car has PLX afr mounted)

locrzn

iTrader: (9)

I had a simular situation, I'm working on mine also. It would want to die as I'm coming to a stop. I know its that cam thats causing the problem and I'm not the best at this but getting closer

96lt4c4

iTrader: (5)

Try to turn off the Throttle cracker in the lower RPM and engine speed areas by zeroing the table out.

Exidous

iTrader: (11)

Aside from the follower usual I also needed to:

Inflate the cooler temp areas of the RAF by 1-2g and let the stit worry about pulling air as needed.
Raise the timing table at 800 by 4* and 400 by 8*. Kind of a catch so you don't loose brake boost.
The low speed areas of the follower are VERY sensitive. Little to much it hangs too little it dies.

greenvortec97

iTrader: (1)

ill do these changes and report back to you guys

greenvortec97

iTrader: (1)

zeroe'd out the cracker table and the problem is very minimal now, still hanging a bit with a slight bit of overshoot. what are some average over and underspeed spark values i should be trying? other cammed cars i've messed with do not do this or are as needy lol

96lt4c4

iTrader: (5)

Sounds like you still need to play with the throttle follower. The lower the delay the sooner the decay starts, the higher the decay the faster the follower closes. Try to shorten the delay. Then you may try increasing the decay which will make the IAC/Follower close faster.

Russ K

iTrader: (1)

Using my idle .cfg file (Just change it to a .cfg as I can't upload a .cfg file here), do a cold start scan in park till operating temp. Don't touch the throttle or move the car while scanning. Then copy the #1 idle desired histogram into your RAF table of your tune, making sure the units match. Then in compare mode with a stock tune, make the differences the same for the temp cells you didn't hit while scanning.

What are your cam/engine/trans/gear ratio specs?

Russ Kemp

greenvortec97

iTrader: (1)

lq4 370ci
231/238 113+3 lsa
ss3600 4l60e
3.70 gear 26" tire

Monte4ever

iTrader: (2)

Do these same numbers go in the Idle Airflow "in park" table too?

Russ K

iTrader: (1)

That is for in park. Then do another scan in gear. The in gear numbers will be higher than the in park numbers.

Russ Kemp

SladeX

I found a tidbit that has helped me with my ac on and hot start which also affects that scenario.

When cammed and both ve and maf tables are all dialed in correctly the base running airflow vs ect needs to be adjusted a lot for bigger duration cams.

Basically when you slow below 3 mph, it uses base running airflow to idle. Think of it this way, you are on the brake and the throttle is shut and you are relying on the IAC to feed it air, except the values its deriving from are stock hence you are starving the engine of air.

If you play with the throttle cracker, you are keeping it in adaptive a bit longer which is fine as well, but the underlying problem is the transition back to base running airflow which is wrong to begin with.

96lt4c4

iTrader: (5)

For some reason, If I use the Russ K idle config, and paste the numbers into my RAF table, my car has a hard time starting and I have to add more air. It gets it close but I have to bump the numbers up a bit to get it to start better.

greenvortec97

iTrader: (1)

fixed this issue a while back.. actually a long *** time ago lol

Car is on OLSD still, was rocking OLMAF for a while till i cracked the maf on a nitrous pass.

lowered my throttle follower values like stated above. no hang, instantly goes to idle after free revs
I raised my Throttle Cracker to 35mph (Lopes like a som' bitch just coasting, I love it)
Zero'd cracker pretty much to 35mph.. Played with over/underspeed spark tables.. over starts at -4 and slopes up to -8.. Under is commanding 8 all across. Spark in park and drive is 19*... Car drives as smooth as ever. only problem is the cold start surging still, I figure some RAF fine tuning will take care of that however