Originally Posted by LaffyTaffy
Finally tested the fuel pressure and these were the results:
Fuel Pressure Test
Note: the marks on the gauge are 0, 10, 20, 30, 40, etc... PSI. If I understand the fuel system correctly, shouldn't the pressure stay at 43.5 psi? There was no fuel leaking from the lines going to the gauge, so does that mean its leaking out of the injectors or the FPR? It seems like the FPR is working at least partially correctly, because it holds pressure at 43.5 PSI. I think the lack of pressure explains the hard start but not the stalling. You can also see that when the fuel pump starts sounding weird, it doesn't generate as much pressure.
Next up is visual inspection of the fuel pump assembly (and maybe I'll actually start the car with the fuel pressure gauge hooked up).
If I was seeing that right and your fuel pressure was dropping to 0 every time the pump finished priming you're pump assembly / the internal check valve is no good. The thing should prime and HOLD fuel pressure, i.e. after you prime it and or come home and shut the car off, if you took fuel lines off, expect to get sprayed with gas. If that thing is going back to 0 that quick, your pump assembly needs replacing.
I think your key here was you saying the "dealer replaced the pump assembly not too long ago" -- ever have a problem like this before that replacement?
Get a walbro, might as well upgrade while your at it, and my money's on the problem going away, assuming I'm reading that gauge right.
I have a strong feeling that noise is the internal gears in your fuel pump having stripped out, pressure dropping to zero, and bam, no more fuel.