Ok tracked down all the information we need to know. I am currently using: 93 civic coupe OBDII integra wiring harness OBDI B18B here is what I am trying to figure out. I have like 3 unused plugs. One I am sure it's just emissions stuff i don't have ,and the other probably secondary o2 sensor? But the wierd thing is that it has 2 plugs that can plug up to the TPS. What is this second plug? The car seems to run fine how it is.