Need helploud noise coming from hipressure fuel pumpbad pump

"Problem:
After 2 yrs of sitt

"Problem:
After 2 yrs of sitting (a Volvo Penta 5.0Gi PEFS), I took the boat out & under load (engaging the throttle) the boat would stall out. I also noticed there was a loud noise/whine (almost like air was in the line) coming from the hi-pressure pump (VP#3588865) and the hi-pressure fuel line leading to the carburator was vibrating alot.

Troubleshooting:
I bypassed the fuel filter, fuel tank, gas, gas line and ran directly to a reserve tank from the filter intake port and the problem still existed using high octane fuel with added fuel cleaner. The fuel cell kit I have is VP#3594444. Fuel is being sprayed from the fuel injectors just fine. Now for the crazy part, I successfully removed the hi-pressure pump and saw there was a alot of deposits inside. I sprayed some carb cleaner inside which cleaned it up and I ran the pump by turning the key to the "on" position and verified it was pumping. I reinstalled it and bingo the boat was purring (no noise, vibrating, and upon full throttle she roared). BUT after about 5-10 mins the noise started coming back slowly until it was back to full decibels and back to square one of it dying.

Thoughts:
My first guess is that the hi-pressure pump is bad but a service tech stated, "It sounds like it is most likely bad but why did it go bad? Is it because it just went bad or is it because the low pressure pump is starving it?" Since a hi-pressure pump costs $200 and the entire fuel cell (incl low-pressure pump) costs $600 this is a very important question. Since both pumps have a service port (I assume for pressure testing) I should probably do a pressure test.

Questions:
1) How can I test the effectiveness of the low and hi pressure fuels pumps?
2) How do I properly bleed the fuel line of air that are leading to the carburators or is that even necessary?
3) What are the PSI spec ratings supposed to be for the low and hi pressure fuel pumps?
4) Does anyone have any recommendations of a good fuel pressure tester?

Any other advice or theories would be much appreciated...thanks in advance."

"After 2 years sitting, the fu

"After 2 years sitting, the fuel tank anti-syphon may be stuck and the fuel system gummed-up. You may want to dispose of the old gas, clean components in the fuel system, and try with fresh gas."

"After 2 years sitting, the fu

"After 2 years sitting, the fuel tank anti-syphon may be stuck and the fuel system gummed-up. You may want to dispose of the old gas, clean/replace choked components in the fuel system, and try with fresh gas."

I don't see any "gummy

I don't see any "gummy" deposits anywhere but please keep in mind I used new gas with fuel system cleaner added to it during the bypass test. The 2-yr old gas was treated with Stabil (which lasts only a year) but I believe last year I added new gas (Chevron 91) to the mix along with more Stabil. I agree though that I should probably change out the gas just in case but my concern right now is how to determine which fuel pump is bad.

"I just installed a hp pump on

"I just installed a hp pump on my 06 5.0 ,, there is port on the bottom of the lp pump,,,should have about 8 psi unfortuneatly I still have a whining hi presure pump,,,, upon hooking up to the lp pump I found that it had 6 psi at Idle and started to drop under heavy acceleration,, so it looks as though I need a fuel cell assy,,, also a low pressure pump can take out a high pressure pump,,,,,,, diagnosis------- low pressure pump can't keep up with the volume of fuel the high pressure pump needs to supply the injector rail with 60 psi}}"

"UPDATE: Turns out the fuel c

"UPDATE: Turns out the fuel cell assembly is not meant to be taken apart even though I was able to. So even though the high-pressure pump on that assembly might have been all that was wrong, I had to buy the entire fuel cell assembly...there went $600. Anyway, all problems have gone away since installing the replacement and I am back on the waterways again."

I have the same noise coming f

I have the same noise coming from my pump and am awaiting a replacement. It looks like the one way valve from the fuel tank had seized and as a result starved the pump of fuel resulting in it overheating. My advice would be to double check there is not a fuel supply problem in case it burns out your new pump.

"Jason, some answers to your q

"Jason, some answers to your questions;
1 - test with volt ohm meter for correct voltage and ground, test pressure with fuel pressure gauge
2 - not necessary, you can depress the schrader valve or use fuel pressure gauge which should have button for depressurizing
3 - depends on the year of your engine. ie 2000 - low pressure 8 psi, high pressure above 27 psi and not higher than 31 psi.
4 - Owatonna Tool Co. OTC7211
There are many posts on this subject read them all. Get your self a shop manual there are many other tests which can be performed."