Signal wire on the o2 sensor to install air fuel gauge

Can anyone tell me what signal wire is which on the oxygen sensor on a 2001 acura integra... i am trying to hook up a a/f guage.... there is a white, green, and two blacks.....
please help
thank you

dont hook it up directly to the O2 sensor cuz u will have to run wires outta the engine bay. just run the sesnor wire of the gauge to the O2 sensor wire on the ECU. it's a white wire on the last row of plugs. it's shown here as PHO2S pin D7 of the OBD11 B16A3 ecu diagram
http://www.autoserve.8m.com/cgi-bin/i/obd2to1ab2.jpg

the ecu is located on the passenger side kickpanel (on the right side of the floor of the passenger side -right in front of the door, u will see a plastic cover held together by a round plastic clip and a big black plastic flat head screw looking clip. remove those clips to give access to the ECU then unbolt the ecu from the brackets use n a 10mm wratchet. splice into the O2 sensor wire and ur done!