question about fuel pump noise and 2 pump setup

[Fendego]

Hey guys, my car was built in 4/87 so it has the dual pump setup. When the car is running there is a terrible noise coming from fuel pump. Keep in mind the car is stripped but still how do I know which pump it is or which one needs replacing? Is it possible that one has already died? I also have fuel cut problems around hard right hand corners. Thanks for the help

ps- if video of the sound will help I can go take some
- Nick

[jlevie]

Generally a loud pump on this car will be the high pressure pump mounted just in front of the left rear wheel. The high pressure pump will make noise if:

the transfer pump in the tank is weak or inop
the fuel filter is clogged
the fuel return line from the FPR is obstructed
the high pressure pump is badly worn

To check the transfer pump, remove the access plate, disconnect the fuel line and replace it a piece of hose pointed into a jug or other container, and jumper the fuel pump relay. if you get no fuel the transfer pump is dead. There's a spec in the Bentley (which I don't have with me) for pressure and flow rate for the transfer pump.

If the transfer pump is operating correctly, replace the filter and check fuel rail pressure and flow (the specs are in the Bentley). A weak or worn that is making a lot of noise probably won't meet specs.

If, as it sounds, the high pressure pump needs to be replaced, pull the transfer pump and sensor and check to see if there is a layer of rust sediment in the tank. Rust is highly abrasive and will wear out a high pressure pump in short order. It will also tend to plug up the transfer pipe between the tank saddles and cause starvation in right hand turns when the tank isn't completely full.

If there is a layer of rust in the bottom of the tank you can replace the tank, or acid clean and seal the tank you have. Do that before replacing worn pumps.

[Fendego]

Generally a loud pump on this car will be the high pressure pump mounted just in front of the left rear wheel. The high pressure pump will make noise if:

the transfer pump in the tank is weak or inop
the fuel filter is clogged
the fuel return line from the FPR is obstructed
the high pressure pump is badly worn

To check the transfer pump, remove the access plate, disconnect the fuel line and replace it a piece of hose pointed into a jug or other container, and jumper the fuel pump relay. if you get no fuel the transfer pump is dead. There's a spec in the Bentley (which I don't have with me) for pressure and flow rate for the transfer pump.

If the transfer pump is operating correctly, replace the filter and check fuel rail pressure and flow (the specs are in the Bentley). A weak or worn that is making a lot of noise probably won't meet specs.

If, as it sounds, the high pressure pump needs to be replaced, pull the transfer pump and sensor and check to see if there is a layer of rust sediment in the tank. Rust is highly abrasive and will wear out a high pressure pump in short order. It will also tend to plug up the transfer pipe between the tank saddles and cause starvation in right hand turns when the tank isn't completely full.

If there is a layer of rust in the bottom of the tank you can replace the tank, or acid clean and seal the tank you have. Do that before replacing worn pumps.

Exactly what I needed to know, thanks!

[Fendego]

Is there anyway to switch to the single pump setup in the late model?

[Mike]

solid rundown, jlevie

[e30trooper]

solid rundown, jlevie

more info pls!

My High pressure pump is loud, very loud.