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Hard start upon initial start up.

Arcticman
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Arcticman New Member

Arcticman

Posted
Posted

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 Senior Enthusiast

CamGTP

Posted
Posted

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.

  • Like 2
swathdiver Senior Enthusiast

swathdiver

Posted
Posted

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.

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