Where is your FPR mounted, and where are you checking your fuel pressure. Also I have seen a little debris caught in the valve on the FPR making it hang partially opened. Can you take the FPR apart and inspect it to make sure it is sealing?

 

I picked up a stock replacement fpr and its mounted on the fuel rail in the stock location.
Are you saying it could be debris in the fuel rail or in the fpr. I just replaced the fpr yesturday

 

Im checking the pressure on the fuel rail on the pass side

 

Hmm. What year truck is this? Just trying to make sure there isn't a regulator in the tank. Also how much boost are you running, and to make sure, you are running pump e10 fuel, and not e85 right.

 

Its a 2003 sierra 1500 5.3l. Boost set to 7lbs. And im not running e85

 

This one is pretty confusing. I don't think you are running past the pumps abilities.

Are there any kinks in the line anywhere? Do you have the ability to check the fuel pressure down by the frame rail to see if it is dropping there? I'm just wondering if there could be a restriction in the line.

Another thing is, how long does it take for your fuell pressure to bleed down when the truck is off? There could be a small leak inside of the tank.

 

Well, I wasnt able to pull the bed this weekend. I did pick up a loaner gauge kit from autozone, I should be able to connect it at the fuel filter so I'll hopefully be able to check that this afternoon. I was able to check if its bleeding out when the engine is off and its been at 50psi for about an hour now.
BTW, thank you for these suggestions as its starting to get frustrating trying to find the culprit.

 

I keep forgetting if you ran new power for the new pump. A drop 1 volt is gonna lose around 50 lph off the pump, and you'll lose about the same with 10psi from the turbo.

 

Im on the stock wiring.
Also, i wasnt able to check the pressure at the filter cause i dont have the right fittings.

 

Where do i test the voltage of the pump