Vortec 8.1 hard cold starting

[Bigbad496]

My '01 2500HD is getting hard to start from a cold start. It spins much longer than it used to until it fires. It used to fire right up. Runs great after it starts. Lots of power. It has 72k miles. Put new plugs and wires on last year.( AC platinum & bosch wires ). Fuel filter changed at 44k. Have run several fuel system cleaners thru. Also had crankshaft sensor replaced earlier this year because it was cutting out sometimes. ( that problem's gone ) It acts like my old Pontiac carburated engine after it has sat for months and has to get fuel pumped up to carb to start. Anybody have any ideas ?

 

[Denali24]

Sounds like the check valve in the fuel pump is bad, this would allow the system to lose gas pressure. The fuel pump is in the fuel tank. Try turning the key to on and wait a minute then try to start, if it starts right away you'll know the check valve is bad. ( the fuel pump when on for that minute it re-pressurized the fuel system )