2000 Chevy K2500 spins fast but slow to start!

[CurtisMcDaniel]

My 2000 k2500 has the older engine as seen in 95- 99 c/k trucks. 5.7 vortec with distributor on rear of engine, 4l80e tranny.
The truck never had this problem until my mechanic changed my gas tank. The gas tank was leaking from a crack in the tank.
I have recently installed a brand new starter so the engine spins over very fast.
But since I got it back from the mechanic, the engine spins and spins and finally the engine will fire and start.
I think they reinstalled the old original fuel pump.
I’m thinking maybe the fuel pump or fuel pressure regulator is getting weak or maybe they were rough with my fuel lines and put a crack in one of the fuel lines and it is sucking air/ losing prime?
What all problems will cause this engine to spin so long before cranking?
Thank you in advance!!

 

[Schurkey]

What is the fuel pressure?

Does the fuel pump prime when the key is turned from "Off" to "Run" before the engine starts?

No prime probably means the fuel pump relay circuit has failed, so the engine has to have oil pressure before the fuel pump will run.

 

[SUBURBAN5]

Also do you smell gas under the hood? Leaky fuel regulator could be bad