Gary, you cannot live map over OBD!
1. Serial programming mode will be corrupted if you try to run the engine.
2. While the engine is running checksum checks are being run all the time . If you try to change any content , before you finish a sum another check happens, ECU content fails the check and the engine stops.
This is even true for a Flash emulator such as OLS300 which is pretty well instant, never mind the MUCH slower baud rates used in serial(OBD).
The only way to change content is to have ignition on, engine off and then download/upload.