I have a 2001 Silverado 5.3 liter (see signature). When I try to start it, the motor turns over for at least 3-4 seconds before it starts. Then, it runs normally. It used to start immediately. If I turn the key to the run position and hold it there for a few seconds, then crank it, the engine starts normally. Is my fuel pump getting weak?

 

Anyone?

 

I think the check valve or whatever its called is bad no big deal. What is happening is when you turn the truck off the fuel isnt staying in the line its going back to the tank so thats why you have to leave the key in the on position for a few seconds to prime it.

 

That makes sense. I figured the system was losing pressure. I was thinking about getting a fuel pressure gauge to check it.
You said check valve was bad, where is the check valve located?

 

I beleave its on the pump it self, Yeah you can hook up a fuel pressure gauge at the fuel rail and see whats happening when you turn the ignition on and then off. After you drive it and park it, how long before you notice it again. Ive seen some right away and some have to sit for hours.But check make sure thats it.

 

Im leaning towards a bad pressure regulator on the rail, its got a bad o ring and its letting the pressure bleed off when it sits. I had it happen to a friend of mine's 2000 silverado last year.