1991 Sentra

HI. drove car to work today,25 miles shut engine off for a few minuts and it will not start,checked for spark and I can hear the fuel pump running.It would not start after I shot it with some either.Battery is good and engine is cranking good,plenty of fuel in the tank.Please,any ideas would be apprecated,Diesel 1962... p.s engine is GA16DE..