1990 Chevy Silverado wont start

Engine problem
1990 Chevy Silverado V8 Four Wheel Drive Automatic exempt miles

drove the truck back from the repair shop. About 10 miles. While in route service engine lite appeared on truck was running fine, took truck to the house and parked it. Next day went out to hook up to my snow plow to service snow plow pump, while sevicing the pump left truck running to keep full charge to pump. Appox, 15min. Truck proceeded to idle rough. Put one bottle of gas dryer in, thought I had a moisture problem. Went to back up. Truck then died. Will turn over hold throttel to floor will try to start but when letting off of the key stops trying to fire. Replaced fuel pump about 4 yrs ago. Did have a smell like the catylidice converter smells and some black smoke while running. Was in the shop for new exhaust the day before still has old converter on it. Singed broken