If somebody be kind enough which wire to splice into to install my A/F gauge, i know you can't rely on it but i got it for free. It's an b18a, i have already searched in the archieve.

 

What ecu are you running??

 

Purple wire connects to the white wire on the ecu harness, its a thicker white wire that is the primary o2 wire. Then the red wire connects to a 12 volt source like the cig lighter, black wire connects to a good ground source.

 

yup what he said above!