Underneath that little cover is the pre-programmed fuel curve for the 22re, physically moving the wire a tooth over will have the perceived effect of richening up the mixture-what its actually doing is richening the mixture sooner in the curve. As the butterfly valve swings open, the little dial in the box also swings over the fuel map, as it swings, it sends a message to the comp to send fuel, moving the wire over, puts it later on the fuel curve, but earlier in the mechanical swing of the butterfly valve. Or at least that's how I understand it. It's also not very warranted on a stock breathing 22re, too much can actually decrease hp. Have fun.