I'm sure this is pretty easy, but can someone help me out on how to install a air/fuel gauge on a b16a3...Thanks

 

Find the primary O2 sensor (one closest to headers) and splice and solder into the white wire. That is your signal wire going into your A/F gauge itself. Look inside the under-dash fuse box and you'll find 5 ports with male taps in it. Number 5 port is your 12v ACC power. Using a male spade connector, connect the power wire from the gauge to this port. Lastly, take the remainder wire (ground) to a good bolt hole and ground it (ring connector) with a corresponding bolt (10mm). Waahlah!...your A/F should glow up once you put your keys in ignition/ACC. Make sure all your connections are good and soldered points are wrapped with electrical tape.