Whats the best way to check out a fuel pump?

[digesterman]

On a 2000 7.3 what would be the recommended way to check out your fuel pump?
Still having problems starting when cold. Can start on ether but it will not stay running no matter what. Given that I am thinking it may be a fuel problem vs glow plugs etc.
When I open the water drain valve and turn the key I get good flow.
Also anyone know of a good code reader that will actually give codes for this type of problem?