does anyone know what wire that goes to the ecu that you splice into?

it doesn't go to the ECU, it splices into the white wire on the O2 sensor harness. That is what everyone on here said way back when I was searching and reading on this. It is also what I did.

Brent

Coach is right it is the white wire,if you follow your o2 sensor wire back to the connector,on the other side of the connector you'll see a white wire that is a thicker gauge than the other two,THAT'S THE ONE.

Just splice into at the ECU for best results.