won't start when switch gas tanks

I have a 1987 Chevy Silverado truck with 167,000 miles and a 350 engine. It has two fuel tanks which were both working fine when I drove to the gas station. I used the left tank to drive there and could switch between tanks on the way. At the gas station I filled up the right tank, started driving away and switched to the right tank and the truck died. When I try to start the truck with the right tank it sounds like it is turning over but won't start. If I switch to the right tank when already started the engine immediately dies. Everything is working great as long as I only use the left tank. Thanks to anyone who can help :)