I have a 1998 silverado with 5.7 vortec. 124k miles It has always started very quickly (the starter dosent even turn the engine one revolution and it is running). Now it will sometimes crank the engine 6 to 10 time before it will start...or sometimes it wont start. replaced fuel pump with ac delco one in June of 2007 (87k miles) also fuel filter. anyone have any suggestions....................Thanks

 

I would start by checking fuel pressure should have at least 58 psi and hold.
If it drops even a few psi will have long crank times.

 

Is there a check valve in the fuel pump? talked to a mechanic and he said if the check valve goes bad then it will crank a lot to build up pressure to start

 

Yes there is

 

Thanks loosebearing and MDTAHOE I have not checked fuel pressure yet. truck runs fine after it starts. I have found out that the truck will start easier if I cycle the switch a few times or if I park the truck with the nose downhill thats what makes me think it could be the check valve

 

I had the same similar problem on my 89 and 91 350ci both, replaced the pump on both, same problem pulled the new pumps and found the rubber hose that connects to the pump had a hole or crack in it bleeding off the pressure causing hard starting or several restarts.

Always replace the hose when you replace the pump along with the screen on the pump and inline fuel filter.

I really did like doing this job twice on each truck to find that the ethanol in the fuel we get now is causing these hoses to go bad..

 

Sounds like a fuel pressure regulator...