Isx wont start

[Unilevers]

until you can see actual fuel pressure when cranking you are wasting your time guessing.

If you have those codes its most likely a bad leak or blown pump.

1 - Get insite
2 - small sniff of ether verify engine will fire (rules out total failure/timing)
3 - Verify low pressure and that lift pump is running constant
4 - Check rail relief
5 - Pop pump head and check check valves/plungers
6 - Isolate injectors and check for leaks
7 - verify rail pressure with manual gauge for sensor plausibility
8- try test ecm