Back to everyone's favorite topic; o2 sensors. After searching for days and no avail I assumed a post was justified. Here's the problem, I bought/took over someones e30 m3 swap project, Ive got just about everything finished properly and it is coming out of paint next week; the last issue is the 02 sensor. I have the bung in on my recent custom fab exhuast ready and an 02 for the obdi 95 m3 (applicable to the bosch 413 ecu which i am using). Anyways, the sensor has the 4 point connection but I am uncertain where to connect it as I did not start this wiring (its a good wiring job though, zionesville). The only connector I can locate is a male 4 pin but it is a screw in larger diameter similar to that of the MAF sensor connection; which will not connect to my female 4 pin o2 sensor. I no longer have my conversion CDs and need to locate a wiring diagram of the bosch 413 ecu or figure out which wires are for the precat o2 and which run to the fuse box. Any suggestions?