Help with my initial AFC tuning please

[snafer100]

Car is a 93 TSI AWD
MODS:
101 comp cams
20g turbo
680cc injectors
fuel pressuse regulated at 43 psi
22 psi boost
stock short block
full 3in exhaust and dejon intake
johnny fmic
dsm chips eprom setup for the injectors and fuel pressure and all the other nifty mods
...if im forgetting sumthing important please let me know

right now i have the afc pretty much zeroed out, the car does run decent, but i really need a starting point, basically an idea of what and how much correction i should be seeing to get this car tuned LT and HT. Now i read a few post dealing with LT and leaning out still the a/f meter cant correct the ratio anyhow and richen it up a tad from there, but when i did thatthe car seemed to stall alot ( also b/s removed and fidanza flywheel, heard that may be part of it). Im hoping someone knowledgeable can give me a guessitmation on a baseline for this, thx ken

 

[JohnCIV_Talon]

Wel if you have a chip for it, the car should be running like stock. You need a logger to do any kind of tuning with the afc. Until then dont mess with anything un less you want to mess it up.

When tuning you being a 1g, want to get the short term fuel trim to 100%. There are ways to do this. You should start with the low throttle. Just sit in your car after it is fully warm and rev it up to each rpm point on your afc. Adjust the afc at each point so it is at 100%. Do this up to 4k. If you want you can just use the 4k setting for the rest of the points or do it while driving. Then use all the low throttle points at high throttle and that will give you a baseline for high throttle.

From there you can start doing logs. Go from 2500-7k while logging, RPM,Timing, and o2. Then you can see where you need to add and subtract fuel. Just post your logs on here if you need help with what and where to adjust.

Im no pro so if im giving bad advice, someone tell me.

 

[snafer100]

i have a logger... im trying to get an idea of of what i should be expecting as in correction factors, ill run some logs on it this week or weekend and post em

 

[JohnCIV_Talon]

Well do what i said, and instead of gettinag a idea of what you need to do, you will have the idea already. No one can tell you, especially with your set-up what your corrections should be. Not even a baseline.

 

[Eastwood95]

High settings are pretty easy once you get the hang of it. You want to Tune for .92 o2 volts with no knock. Timing should steadily increase from the point you go WOT to redline. If your timing holds or drops at any rpm, you have knock and you need to richen up that rpm point. You should be able to log knock on a 1g as well to double check.

With 680's, you will be pretty far into the negative side of the correction's on your settings. Like said, each car is different, so I would log it first with the SAFC settings at 0, and go from there. If you're running rich (.94 volts or higher), drop the HI settings into the negative at those respective rpm points.

Did you read these yet?:


http://www.roadraceengineering.com/newafc.htm

http://www.roadraceengineering.com/newafcsetting.htm

 

[snafer100]

ok i went to set my low throttle setting today using MMCD. When i started the car and let it warmed up i plugged the logger in and was watching RPM/ O2 / KNOCK / and FTRL low trim, It was at 135ish%, (1000rpm) i got it corrected to 99.4% kinda jumped up and down just a tad, like less then 1%, I went to go to my next point 1600 rpm and it got stuck at 90%, no matter how far i changed the afc settings it would not change, i tripple checked the rpms, and where my setting was, and i could definately hear a change in the way the car was running. So now Im frustrated and i unhooked the battery for about a minute and hooked it back up. I started the car and left it run about 5 minutes and checked the logger again... Now its stuck at 100% no matter where i change the settings.. So now im wondering if its stuck in some closed loop mode so i drive it around the block a couple times and it is still at 100%... No way... Only thing i can think of is for some reason im throwing a knock code at idle.... when i tap the gas it kinda dies a bit and sometimes has a couple counts of knock.... What the hell is going on???? The wiring has to be correct cause i can most def feel a change when i adjust it. Is this knock code screwing me?? please help
Ken

edit btw, when it was working for the first setting i had it at +16% for the 1k rpm point, just for info and the 02 sensor is working fine