my volvo 940 ran out of gas and my dad and i proceeded to put in gas and attempt to restart but nothing happened it turns over but it doesn't seem to ignite or startup, according to my dad he ran the thing completely empty he said it was sputtering and then just died out. He came to the conclusion it might be the fuel filter collecting sludge from the tank because he ran it so dry, and the fuel filter became clogged, im thinking it could be more serious such as the fuel pump burning out. Is there something i can do to check if the fuel pump still works? or is there an easier solution im not thinking of. it has gas in the tank but its not starting up.