* Is there any way to check the fuel injectors to make sure that they are not plugged up and that they are allowing fuel to pass thru ????

The engine cranks over fine and sounds like it is gonna start but it wont. I put new spark plugs in and they all have spark, i replaced the fuel filter and checked the fuel pressure at the rail ( 40 pounds ). Also checked injectors and got 12 volt supply and negative pulse. Any ideas or what should i do next ????