testing fuel pressure regulator and crankshaft position sensor

I have read in previous posts that you can test the fuel pressure regulator and crankshaft position sensor but no one mentions how.

So I am asking does anyone know how?

Thanks for your help.

You need a fp gage hooked to the port on the injector rail for a fuel pressure test, a resistance test can be done on the crank sensor but if the engine starts and runs the crank sensor will always pass any test, basically.