You can use OBD-1 for trouble codes and some limited diagnostics and I'm not sure exactly what is was or what it was called but, I just recently redid my 85' at my friends speed shop and he had it plugged in somehow and was tuning my car with whatever he had. I'm pretty sure it was limited information he was able to observe,(not as much as a scantool produces) but it was definitely better than nothing at all. Sorry I don't know what exactly he used but I guess I just wanted to assure you that something other then upgrading your Ecm and everything else that goes with it $$$, does exist. I will reach out to him and ask him what it is. Some other members are sure to post more tangible information over the next few days as well. My name is Jimmy and congratulations on your new hotair GN ie: (welcome to hell) and welcome to the forum! Alot of great folks here with everything you need to know about turbo buicks, purchase and sell for turbo buicks, and network with some really great people throughout the turbo buick community! Good luck.