AFM Tuning?

[RobertK]

I'm not sure if this has been posted before but the search didn't bring up anything related to my question.

The AFM on my car is one that I picked up off eBay when fixing my car up this summer. I also installed the 19lb injectors. I've been driving the car just fine for about 2-3 months with no problems except when I take the car up to and past 5000rpms it runs rich and blows out lack smoke. When I drive regularly (ie. shift between 3000-4000rpms) it does not run rich at all. I've enve pulled the spark plugs and they look fine (tanish/greyish color).

I guesstimated the AFM when I orignally installed it. I just tighten the wheel until it didn't run rich at idle anymore.

So I guess my main question is if there is a certain way to tune/adjust my AFM for the correct mixture or if I'm just running rich @ higher RPMS because of the 19lb injectors.

[MrK]

well if by 'wheel' you mean 'spring', then you're pretty much out of luck. According to the FAQ and DIY here, adjusting that on the AFM pretty much renders it partially flawed for life. Good luck.

[RobertK]

I'm aware of that but I've heard of people adjusting it and then disconnecting the O2 sensor when the engine is warm to see how it idles.

I might not be able to get it perfect but I would like to try and tune it the best I can.

[chuckybob]

if you set the idle air adjusting screw to its absolute middle, you MIGHT be able to reset the afm spring to default. maybe. I'm not sure how well mototronic adapts to AFMs being off, but on an l-jetronic system, if the idle air adjusting screw hasnt been fucked with, its signifigantly less of a problem, just adjust the spring till the CO mixture is right.