Why won't OBD II work in an e30

[Avus_325is]

I have looked around and can't really find an answer. I mean couldn't you just dummy all the fault codes somehow and run it just fine? The o2 sensor ones wouldn't be a problem because dummies of them are already made to allow you to run track pipes with obd 2. Could someone just shed some light on this for me. I'm not doubting it, I just wanted some info since all i've ever heard was "It just won't"

[Jordan]

"It just wont" is as technical an answer you can understand.