Ok, so if the fuel pressure is 45-50 with the key ON and the engine OFF then you dont have nearly enough pressure to start the truck. You most likely have a bad pump, AC Delco usually doesnt fail that quick but they have been known to every now and again.

 

I was afraid of this, are they good with the warranty on their pumps?

 

Something to keep in mind when checking fuel pressure....

On 1998 and newer, you can activate the fuel pump continuously to test fuel pressure. Apply battery voltage to the pump prime terminal in the underhood fuse panel. After you obtain a steady pressure reading, remove voltage from the terminal. Fuel pressure must remain above 55psi for at least 10 minutes after you remove the voltage. These two tests check the overall condition of the entire fuel delivery system, (fuel pump, pressure lines, injectors for leakage, and both functions of the fuel pressure regulator). If it fails one or both tests, it does not tell what the problem is, it only tells that a problem exists. Further testing is necessary to pinpoint the problem. GM does not publish any "engine running" fuel pressure specs for this engine, there are far too many variables involved.



Post your results.

 

Turns out my fuel regulator was bad, got that changed, got steady but low fuel pressure, warrantied the fuel pump, put new pump in and started right up. Temperamental truck. Now I got a new problem that i started a new thread with. Thanks for the help with this though.