1999 Ford Crown Victoria - Cranks but won't start. What Sensors would prevent a car from starting

more than likely the computer sets the timing , if you move the distributor it throws the crank and cam sensors out of sync , fuel pressure should have been checked before replacing the pump , do you have spark ? Who replaced the timing chain the " "mechanic" " ?

Sorry to not be clear, this might be even more confusing, but here goes. Spraying starting fluid does allow it to run for a few seconds, so there is spark. The fuel pump primes when the battery is hooked up, but does not continue pumping when the key is turned. Timing : I did the timing, and know the right cam was skipping whenever the timing slipped, when replacing the old parts with new I attempted to 'reset' the timing by comparing crankshaft position marks, (The bump being straight up and the timing mark about 15 degrees off to the left) and making sure the right camshaft was at top dead center, (this was approx. 11pm with the timing mark on the sprocket on the right side) then compared firing order for the cylinders, thinking when 1 is top dead center, 5 should be all in) (This made the Left side be at approx. 12pm on the left Sprocket) I then manually advanced the crank and cams to check and had no resistance. After It didn't start I brought it to a Mechanic to check and (Hopefully fix whatever I broke) - ie. the timing, they told me the timing was fine but I somehow had a fuel pump failure. I call them a "mechanic" because the new fuel pump does exactly the same thing as the old ... and I no longer have any faith in their ability to fix or diagnose my problem.