Air/fuel ratio guage help

[WRXVinny]

I installed and AutoMeter Comp Air/Fuel ration guage. It has three wires on it. Purple, black and red. I take it red goes to the positive terminal on the battary and black is ground and purple goes to the signal. Well I hooked the purple wire to the white wire of the O2 sensor behind the downpipe. The O2 sensor has 3 wires: white/blue/black. I hooked it to the whirte and whwn I start the car it is on the red zone (lean) and one bar lights up all the time no matter if I give it gas or not. The car was not warmed up by the way. Anyone can help me please? Also I heard you can hook it to the ECU box but which wire does it splice to and where is the ECU? Thanks guys in advance!

[wrxrolla]

Do you have a wideband o2 sensor?

[boosted scoob]

If you wire up an a/f gauge to the secondary 02 sensor (narrow-band), it will give erroneous readings. The secondary 02 sensor on WRXs do not read the same as regular 02 sensors.