Still starting hard, looking for suggestions.

[Cowboy Tom]

Morning all,
I replaced the fuel pressure regulator and fuel filter. Truck still takes two to three tries to start. I hooked a pressure gauge to the fuel line and got:

After setting all night: 0 psi
Turned key to on: 40 psi
While cranking engine: crept up to 55-58 psi and engine started
With engine running: 55 psi
After turning engine off: 62 psi
After setting an hour: crept down to 50 psi
Turned key on: 59 psi and then truck started right up

I replaced the fuel pump assembly last year with an aftermarket pump from Kragen's auto supply. Anyone have suggestions on what to try?
Thanks.

[gilias16]

Originally Posted by Cowboy Tom

Morning all,
I replaced the fuel pressure regulator and fuel filter. Truck still takes two to three tries to start. I hooked a pressure gauge to the fuel line and got:

After setting all night: 0 psi
Turned key to on: 40 psi
While cranking engine: crept up to 55-58 psi and engine started
With engine running: 55 psi
After turning engine off: 62 psi
After setting an hour: crept down to 50 psi
Turned key on: 59 psi and then truck started right up

I replaced the fuel pump assembly last year with an aftermarket pump from Kragen's auto supply. Anyone have suggestions on what to try?
Thanks.

My truck is doing the exact same thing, let me know what it was when you figure it out. thanks
[email protected]

[sherman69]

you didn't say what year the truck is.
On my 97 5.7, it was doing the same thing as you describe. But then after several weeks of that, we went on a trip. after 100 miles at a rest and pit stop, it wouldn't start and had no fuel pressure. (I started carrying my pressure gauge in the tool box)
Got flatbed towed home.
So I found the 13 month old Carter fuel pump was bad. I took it apart and it was siezed up. The pump motor looked like it melted. I guess the comments about not running the tank below a quarter tank must be true.
I replaced it with a Delphi and it's doing fine and starting immediately again.
Bob B

[2000CAYukon]

40 PSI is too low for the Vortecs to start. It should jump to 60 or higher when you first turn on the key. Since the regulator is new, it sounds like your pump is on the way out.

//2000CAYukon

[Cowboy Tom]

Sorry I posted year ealier. 1998. I replaced the fuel pump assembly last year with an aftermarket. Do I have to buy the entire fuel pump assembly, sending unit and all, or just the pump? If so, how much is just the pump from the GMC dealer?
Thanks.

[sherman69]

Yes you need 60 lbs pressure.
Go to GMpartsdirect.com and pick your way through the catalog.
My 97 K1500 pickup 5.7 only needed the pump for way less than $100, But a friend has a 97 tahoe 5.7 and his required the whole thing for about $350. They did some changes around 97. Some need the whole unit and some don't.
Bob B