2000 Chevy Silverado 1500 fuel pressure

God bless you my brother's and sister's!

Well I got this truck in for a quick check long crank. I checked fuel pressure key on no crank needle moves to about 12 psi and drops next key cycle to about 30 psi and again drops. When I cranked the truck it starts after second crank and fuel pressure is 45 psi without vac it's 50 to 55 psi. The pressure drops to zero immediately after truck is turned off. Customer had to go so no time to check really I do know the pump is working I hear it turn on when key is on the on position. When customer comes back I would like to have a ideal of what could be causing this. No leaks no fuel smell from tale pipe no misfire only code is a knock sensor.
Thank you for your help.

Hey Gilbert!

This is a return system, which means you have tworked ways to drop rest pressure. Well, three, if you count a stuck open injector, but you'd have white smoke out the tail pipe and a misfire if that were the case.

The other two are the regulator itself, and the check ball in the pump. To eliminate the regulator, you'll need to either pinch the return hose if it's rubber, or installed a shut-off valve in-line behind the regulator. With the valve closed, rail pressure should hold with the pump off.

If it doesn't, and there are no external fuel leaks, then you're down to the pump itself. Or, you can install a shut-off in-line on the pressure hose coming into the rail. Leave the valve open, run the pump, then close the valve. If pressure holds, the regulator is good.

Does that make sense? Post back if you need clarificafion. Also, there's a ScannerDanner video that shows some of the procedures I'm talking about:

God bless you my brother's and sister's!
Hey brother Tyler it's good to hear from you thank you for your help the video was helpful. I did understand all you said just one ? Is the check valve part of the fuel pump assembly or the fuel pump itself.

gilbert wrote: God bless you my brother's and sister's!
Hey brother Tyler it's good to hear from you thank you for your help the video was helpful. I did understand all you said just one ? Is the check valve part of the fuel pump assembly or the fuel pump itself.

The check valve is part of the pump assembly

Tyler wrote: This is a return system, which means you have tworked ways to drop rest pressure.

Tworked, LOL. You guys gotta call me out on stuff like that :lol:

Anyway, yep, part of the assembly. I've never been able to find them serarately. Let us know what you find!

God bless you brother's and sister's!
Brother Tyler it took me a minute to figure it out but I did. LoL
I will keep you posted if the truck comes back thank you very much for your help.

God bless you my brothers & sisters!

OK so i got this truck with the same symptoms the only difference is the year it's a 02.
Brother Tyler i did pinch off the lines and when the fuel supply line was pinched the pressure held.
Now by what i understand is the fuel pump check valve, in other-words it's the fuel pump it self or do i have to change the hole assembling?

Thank you for your help.

Hey Gilbert! Yep, if you pinched the pressure hose and got the pressure to hold, then you're looking at a pump check valve.

You're looking at a pump assembly in this case. To my knowledge, the check valve is separate from the motor and not available separately.

God bless you my brothers & sisters!

Hey brother Tyler can you point out which one is the check valve? I'm going to recommend the hole assembly but i would like to know.
Thank you for your help.

God bless you my brothers and sisters.

The fix to this was replacing the fuel pump assembling the truck holds pressure and starts right up.
Thank you all your help.