Adjusting AFM

[sjwcougs]

I have seen several posts mentioning a out of tune AFM could lead to rich running conditions. What adjustments can be made? I see the one allen wrench fitting. I have played with that and the result was interesting. The car would idle fine with the hood open and then when i shut the hood it would die out. The car is running ok, right now, but curious as to what this adjustment does and how to make sure it is correct.

[rlux4]

I have bad news for you. The AFM is a factory sealed unit, and by tampering with it you've voided the warranty.
Seriously, is there a reason you have been "playing" with it?
As far as how you know if it's set correctly, if it's at the factory set point, it's correct. The ECU reads resistance from it and the numbers are: between terminals 6&8 on the ECU, no more than 600 ohms. Between 7&8, no more than 1200 ohms. Between 8&9, no more than 350 ohms.
The only adjustment Brad Artigue mentions in his manual is to trick the ECU into running the engine richer. This would be done by changing the flap tension spring.
Ron

[So Cal Mark]

do not adjust the spring tension, the afm will not work properly. You can adjust the potentiometer inside, but unless you have air/fuel ratio meter you will have a really tough time setting it. Even adjusting the air bypass screw without an a/f meter is just guesswork

[sjwcougs]

So in my original post I had mentioned this allen wrench fitting on top of the AFM towards the back right of the unit if you are looking at it from the front of the car. I didn't open anything up on this unit and adjusted nothing on the inside. It is on the outside of the airbox. What is this?

[rlux4]

Ohh, I, and Mark also I bet, thought you were adjusting something under the lid.
I looked at the fitting your talking about, can't really tell what it is by looking in the boot end. So at this point I, for one, don't have a clue.
Ron

[So Cal Mark]

you are adjusting the air fuel mixture with that allen screw. It allows air to bypass the flap. Opening the screw will lean the mixture since it allows air into the intake that isn't metered. Closing the screw obviously does the opposite. Still, without any way to measure the CO out the tailpipe, you're guessing at the setting

[sjwcougs]

Thanks fellas.

[htchevyii]

Ohh, I, and Mark also I bet, thought you were adjusting something under the lid.
I looked at the fitting your talking about, can't really tell what it is by looking in the boot end. So at this point I, for one, don't have a clue.
Ron

From the factory there is a plug in the hole to make it harder to adjust, so you may not see the allen. Here is a link to AFM fuel richening, (the screw only idle and very low rpm). I don't know it it's a good idea or not, but I suppose you could always change it back.
http://www.hiperformancestore.com/Ljetspider.htm