ok i've hooked these up before on single wire 02 sensors but i think my car, 94 civic ex, has a 4wire o2 system. i think it's heated. which wire would i tap to get my af gauge to work. i already know about the power. just need to know which wire's gonna supply the signal to my af gauge. thx a lot. and yes i searched.

 

???

 

First off you need a wideband to get an accurate reading. If you want a cool light show then you need to tap it to the white wire on the o2 sensor.

 

for tuning i'll use a wideband... but the af is just for looks. i'd probably upgrade to an egt when i get a chance but i got these for free and they look good. so thx. white wire it is

 

Don't go off the O2 sensor. Go off the white wire on the ECU. Get a pinout schematic off of here and just tap in there. Then when you change out you'rte O2 for tuning, you are not messing with the other wires. Plus it is a cleaner install.