Obd2-1 questions

My 94 pickup has reached the end,..so i bought a 99 suburban.
I have the 5068 pump on the pickup, and i have a custom chip for it,.
To get a "tune" for the obd2 is out of budget,.
So the question is, what would be in order to convert the 99 back to obd1?

I am getting the burb on saturday, i have never owned an obd2 truck, are the ecm's totally different or similar?

Thanks
Nick

The OBD's are completely different. No interchangeability. You would have to downgrade the entire harness (cheaper to just buy another pump). Your 5068 pump will probably work, as is, though.