I'm kinda new to this Diesel stuff I have 99 2ed gen the truck was shutting down on me then didn't run at all a mechanic told me it was the fuel pump(it wasn't) so I changed it out no power at the plug. Ran a hot on a switch to the pump still no start pump runs still no start. I was told it could be a short or the ecm yes the relay was changed also because it was getting hot . Could it be the injector pump .Any idea or suggestions on what I should do would be a big help.

 

I strongly suggest that you work through this:
https://www.bluechipdiesel.com/vp44_diagnostics.html

Especially the part where you hot-wire the injection pump.

By that you can rule out a lot of other potential issues that cause a no start condition and that would make you throw an expensive injection pump on an engine without solving the issue.

 

Got fuel in it?