It could be many things as carl has already said. Try your pump to see if it is supplying fuel.This is a good way to check you pump voltage and see your fuel rate. Check voltage to the pump and see what it records (ideally it should be around 12v). Undo the fuel pressure regulator return pipe. Place a jug under it and see how much comes out. Only leave it on for 20 seconds for this test

10 volts at pump should read 0.46L minimum
11 volts at pump should read 0.6L minimum
12 volts at pump should read 0.76 minimum