Fist. Never hear of obd-3. To convert you will need Distributor and ecu for obd-1 or obd2. What ever you want to convert to. OBD-1 you will need to use a p-72. GS-R ecu. You will also need a conversion harness for obd0 to obd-whatever you want to convert to. VR-4ever makes them, or and shop, like millenium can get them for you.