- 2004 5.7gxi-F 3869260 4012119425 Duoprop
- 530 hours on the block (heavy overhaul as the engine was partially submerged during Hurricane Sandy.. Most parts new, but fuel cell original)
- Used in brackish water
- Religiously run engine with fresh water after every use.
I had the dreaded whine and substantial heat in my high pressure pump, and just bit the bullet and bought a whole new fuel cell. After I installed it, there was a definite improvement:
- Hi pressure pump is cool
- Have 50 PSI on the high side
- No whining
- Engine sounds good at idle
- I can feel water moving through the cooling jacket of the cell and out the port riser
However there are still a few strange things:
- At idle (in gear) my low pressure pump is 18 PSI (according to the manual it should be "8PSI +-2 at load")
- At 2500 RPM under load the low pressure pump is 14 PSI
- At 4000 RPM under load the low pressure pump is 10 PSI
- At 4300 RPM under load the low pressure pump is 10 PSI
- At WOT my max RPM is around 4300
https://youtu.be/j5rVgDwcBJY
Before I swap out a different brand new pump (Dealer was quick to give me a new one free of charge), are these specs normal given that the service manual states that the low pressure pump needs to be "8PSI +-2 at load"? Parts guy was uneasy with it being 18psi in gear at idle.
Asking the group: Should I swap a new fuel cell in, or keep the current new installed one as these specs are seemingly in line because the readings are only relevant at significant loads? If 18psi is considered too high at idle (under load), Is there anything in my setup (outside of the new fuel cell) that could be causing the pressure to be that elevated?
Also, the WOT max of 4300rpm doesn't seem right either.. that could be end of season fouling of the hull (haven't used boat in the past month).. but if there is any thing you guys might suggest that would cause the seeming loss of power (considering the newly installed fuel cell), I'd really appreciate it.
Thanks!