I a little confused what exactly the differences are in all the ODB's. I understand in 92 pretty much everything went to ODB1 and then in 96 to ODB2. But other than a stupid diagnostics port under the dash and an extra o2 sensor on ODB2 what's the difference. Everything should be in the ECU. I keep hearing that you can't use an ODB2 engine in an old car unless you have everything ODB2. I can't see what possible difference it would make if you dropped in a D16Y8 into a D16Z6 car other than maybe the distributor. Far as I know the ECU wouldn't know any difference and everything should run fine. I have a 90 CRX with a D15b2 and plan on doing a very mildly built "mini-me" with the D15b2 block and Y8 head with a D16Z6 ecu and odb0 to odb1 conversion harness but really couldn't understand what the difference was and why I would even need to get a conversion harness as long as everything is pinned out properly on the the wiring harness and connectors.

Thanks,
Bruce