Firstfives.org

<Posted this in another thread , but wanted to post again in it's own thread.>


I threatened several months ago to post this, but never got around to it (sorry, Peter!). This is an AFM calibration instruction document I got from Metric Mechanic over ten years ago, and have their permission to post it publicly. It's just a digi-pic of the instructions, so it is what it is. It can be found here (there are three pages):

http://i99.photobucket.com/albums/l309/ ... ion001.jpg

http://i99.photobucket.com/albums/l309/ ... ion002.jpg

http://i99.photobucket.com/albums/l309/ ... ion003.jpg

Perhaps we can add this to the FAQ.

Thanx very much Lenny! I just printed everything for me to study.
Big help! Now I can go mess up one of my AFM's! GripGreg

my two cents worth
I used a slight modification of the procedure from Metric Mechanic. Knowing that the idle mixture screw did not affect running at speed, I did the AFM spring adjustment at 3000rpm. Once I got a fairly stable voltage reading around 450mV at that rpm, I dropped back to idle and used the mixture screw to get around 450mV at idle. Then there was the day our county extension people were offering emission checks for cars (we do not have state inspections in KS) CO, HC, and NOx were all below spec thresholds with that AFM adjustment, but they told me the O2 level in the exhaust was too high (!?WTF). Does that mean the car is making oxygen??

And note that you really need a high impedance voltmeter. O2 sensor does not have enough output to develop significant voltage into low impedance.

Great post...
Great info...