A/F Gauge Hook up (Narrow Band)

The best way to tap into the O2 sensor is to:
1) key out of the ignition, unplug the battery.
2) remove the connectors going to the ECU.
3) near one corner of one the large ECU connector you'll see the O2 shielded wire. There is another shielded wire on the other end of the connecter - actually IN a corner - DON'T USE THIS ONE! That is your tachometer signal to the ECU. Anyway, on the shielded wire for the O2 sensor (it'll have green+red and yellow+black wires on either side of it) tap into the O2 signal at the connector pin. This way, you have the shortest wire possible to your A/F guage and you are well away from the noisy ignition system. You don't need a shielded wire to your A/F guage this way.

also.....the ECU has a seperate ground signal which goes to the TPS,ISC and coolant temp sensor plus a few other misc things (check your wiring dia,its pin 4 on the ECU I believe). to get an ACCURATE reading on your A/F YOU NEED TO USE THIS GROUND.......this is where I tapped my ground for the A/F, I used the coolant temp sensor. A/F seems to react slightly quicker and now I know its accurate