Hard start upon initial start up.

[Arcticman]

I have a '06 Silverado 4.8 liter with 76k miles. It cranks on initial start up and won't start. The second time I turn the key it starts right up. I'm trying to find out why it doesn't start on initial crank? I've replaced the fuel pump in Feb '23. I replaced the pump because of the hard start problem. I still have the same problem after the fuel pump was installed. I was told the fuel pressure was good both running and while it sat overnight. I also can't figure out where the pressure regulator is either. I've been told it's on the rail but it isn't there. I was also told it's part of the fuel pump. What are the odds the pump and or regulator are bad only being 7 months old? Is there anything else that can cause this hard start?

Thanks Chris

[CamGTP]

The regulator is built into the fuel pump.

 

What brand of pump did you install. The only brand that should be used is a Delco/Delphi/Denso pump. The aftermarket pumps just don't last.

 

I would be hooking up a fuel pressure gauge to the rail and see what happens. You'd want to see the pressure spike to 50+ psi and hold there and it should stay there while cranking and running.

 

You could also clean the throttle body if you haven't, a dirty blade could cause hard start issues but isn't as likely in some cases.

[Arcticman]

Thank you for the info. I will check those things you have mentioned. 

[swathdiver]

When you turn the key on, the pump runs for 2 seconds to prime the fuel rail for starting.  It may take 2 or 3 key on attempts to get the pressure up as high as possible for testing.  Basically the specification is 50-60 psi.  Pressure should not drop more than 5 psi after one minute.  

 

Put a manual fuel pressure gauge on the truck and do these two tests, watching the pressure build up and then bleed down.  If she passes both, the problem lies elsewhere.