Just put in my boost and AF Mix gauge and I'm having a problem with the AF gauge I got from Summit. Everything is plugged in correctly and the O2 sensor I have only has a single line coming from it. (btw, i own an SR20DET) What's going on is this: the AF gauge is reading irregularily even once the engine is warmed up.
the summit gauge works by having 10 led's light up. Lean ->red red orange orange green green orange orange red red <-rich under normal conditions it should read up to the 1st green bar which denotes 14.1:1 ratio. what i end up getting is a wildly fluctuating gauge that will go full lean when the engine is at idle, but once i begin to press load to it, it will go up to the greens and then randomly fall, then rise back again.
i'm hoping it's not the O2 sensor sense that was new when the engine was installed 5k miles ago.
AF gauge Problem
Sounds like your AF gauge is working just fine. When your car is at idle, or light throttle, it's operating in closed loop. What this means is that your ECU is constantly adjusting how much fuel is being delivered by reading your oxygen sensor. That's why it usually just bounces up and down. The only time your gauge will be accurate(figuratively speaking) is when you are at or near full throttle. Your car will go into open loop, and ignore the oxygen sensor readings. That's when your AF gauge will level out and show you how rich/lean/stoich you are running. This is just the limitation of running an AF gauge.
$350 http://www.tuneyourengine.com I got one and its phizzat. I used to have a techedge 1.5 But i like this one better