signal wire

I'm trying to install a performance chip on my 03 VFR...the install instruction tell me to connect to the "signal wire" going to the O2 sensor. there are 2 white wires, a black and a grey wire...what could be the signal wire...any help would be appreciated

Thanks

 

what kind of "performance chip" did you get? and are you sure you want to install it on your bike?

 

it's from a company called Magnum Tuning. The product is called Dyno Boost. I should trick the ECU into making a richer fuel/air mixture...another member said it did the same thing as a Power Commander, but for only around 60 bucks. I'll give it a try.