6.5l fuel problem
 

I have a '94 6.5l with mechanical pump. The fuel shut off is worked by a toggle on the dash. the other day my buddy borrowed it and tried to start it and forgot to flip the switch. now it wont start. could the pump have sucked air when turning over with the fuel off? I wanna see what some opinions are before i see. i work mornings and college at night. so i dont have time to mess with it most the week. Thank you

i finally had time to look at the truck and switch stopped working. got new switch and starts just like my cummins