water pump 4m40

What do high and low Fuel pumps do?

What do high and low Fuel pumps do?

I have a VP 5.0Gi PEFS engine that wont go past 3000 rpm under load. (easily does it in Neutral). I dont know exactly what the High pressure and low pressure fuel pumps do and am thinking it may be one of them. I replaced them with aftermarkets beginning of last year and started developing this problem mid season and it seems to be getting worse. I checked compression - good Timing is good and advances properly. any adittional information is appreciated, im worried to drop the cash on OEMs on a hunch thanks

The lower pressure pump delivers fuel into the fuel canister. The high pressure pump delivers fuel from the canister to the fuel rail. These pumps have been problematic because the fuel pump manufacture painted the inside of the assembly with black paint. Ethanol in the fuel reacts with the paint and causes the system to be contaminated with paint chips and goo. Here are a few things you need to do assuming your engine is proper tuned and that isn't the issue:

1) clean the fuel regulator screen. If it was clogged with paint chips, your injectors will be dirty too. 2) replace the anti siphon valve on top of your fuel tank. It's cheap insurance. 3) replace the fuel line going from the anti-siphon valve to the fuel pump. The lines get gummy and collapse from the vacuum created by drawing fuel through the line. 4) clean off the electrical connects to each individual pump and reinstall with dielectric grease. These connections must be in extreme working order or the pumps stop functioning properly. 5) change your fuel filter Hopefully, these things will remedy your issue. I had the fuel pump issue myself and after performing these things, my boat is running strong.