Cars use in-tank pumps turned by brushed electric motors. Why don't they blow up when empty? Even in an empty fuel tank the vapors are way to rich to ignite.

Cars use in-tank pumps turned by brushed electric motors. Why don't they blow up when empty? Even in an empty fuel tank the vapors are way to rich to ignite. You might get a good flash if you introduce air and ignition at the same time but odds are you won't get any sort of sustained fire.