The CO at idle is what it is ment to adjust, on a stock car after 2000 rpm everything is supposed to be by the O2 sensor. My AFM screw was tampered with by the PO, we varified on 2 other NAs that were not tampered with that the screw is about 7 to 8 turns from bottom which correspond roughly with the shadow on the side of the AFM screw hole on my car, close enough to pass the smog test.

 

you adjust it at idle, but it affects the car throughout the rev range, closed loop or not

 

ya, thats right. I've messed around with the AFM screw after the installation of my rebuilt engine, and it sure makes a noticable difference in the way the car responds throughout the rev. range.

 

I never messed with the AFM screw, but I did adjust the wiper to contact a fresh part of the resistor strip. I have a new O2 sensor, new injector seals, I pressure cleaned my injectors, new fuel filter, and new FPR. I don't drive that aggressively. My mom gets 25mpg in her 84, and when I let her drive my car one day, she got about the same economy as I do: 18mpg or something. The only thing I can think of is that my DME is set to run richer (the car DID previously have fuel injection problems, so maybe the PO turned the fuel quality switch to try to fix it, and left it at rich?

Arash

EDIT: Sorry Stig, didn't mean to hijack the thread, but my problem is directly related to your question about rich = power. My car is obviously running too rich right now, since it gets poor gas mileage. My mom's car isn't running rich: 25mpg. My car has more power than hers at low-rpms (like 2000) but I can feel that my car dies out at like 5000 rpm, but I can take hers all the way to 6 before I feel a dip in power. So from my experience, richer just means a little more power at low rpms and much less at high rpms. I could be wrong, this is just what I have felt, no dyno runs here.

 

Jgleano, in your previous post on this thread you stated that you were worried about the smog test, just to let you know that once you have tampered with the AFM screw there is a chance that with or without the Wilk Chip installed your car could fail the smog test unless you put it back close to the stock setting.

If you are planning on buying the Wilk chip read the info on the FRWilk.com web site regarding tampering with the AFM.

http://www.frwilk.com/944dme/p_prom2.htm

In a nut shell, FR Wilk makes a great product for the NA but it the car is NOT maintained properly or if it is out of spec the chip will NOT work like it is supposed to.

Good Luck