1985 Buick Riviera wont start

If it sat for more than 6 months then the fuel tank/lines/filter should probably be cleaned out , 85 was transition years going from carburetor to someones idea of TBI , check for spark , You could probably dump a little gas down the throttle and see if it will fire up . It sat there for a reason

Check for fuel, spark, and compression. In that order. Spray a little starting fluid down the throttle body or carburetor. If it runs for a few seconds on that you have a fuel problem. If it won't run on the starting fluid check for spark. If you have spark and fuel (the starting fluid) but it still won't run it's time to do a compression test. If all cylinders test very low or zero it's jumped timing or the valves are stuck open from sitting. Hope that helps! Jim

ignition module in steering column and /or starter relay may be out.