Whine from in-tank fuel pump

[Jack Schmidt]

My 2003 4L is running fine. I'm just worried about it before we take a long road trip.
I can hear the high-pitched whine while I'm in the cab, the engine is running, and the windows are down, but not when the windows are up.
I tracked it to the low-pressure fuel pump by getting under the truck while the truck is running, just like you're not supposed to do.
Maybe the noise has gotten louder but it could be my imagination.
I replaced the pump assembly a couple years ago with a NAPA version.
Should I replace the pump again? Or is this noise nothing to worry about?

 

[Curious Hound]

How full is the tank? The pump will seem louder with an empty tank. A full tank absorbs and deadens the sound more.

The fuel also cools the pump. If you habitually run around with very little fuel in the tank, that can potentially reduce it's lifespan because it will run warmer.

 

[Josh B]

I used to run my 93 low on fuel almost continuously. I carried a gallon of gas in back so when it ran out I would use the gallon and know I had to get somewhere within 20 miles It does make a bit of noise running it low but fortunately I never had any serious problem

 

[Uncle Gump]

First of all... it is a high pressure pump.

I can hear mine at times. Lower fuel level and seems when I'm sitting next to a building... think drive thru window.

 

[Jack Schmidt]

Thanks for the replies.
The whine is the same whether fuel tank is full or empty.
Almost every time I fill the tank I fill it completely, and I always run it to about 1/8 tank.
I called it "low-pressure pump" because I thought there was a high-pressure pump somewhere near the fuel rail. I guess there's only one fuel pump in this pickup. Thanks for the correction.

 

[Jack Schmidt]

Thanks for the replies.
The whine is the same whether fuel tank is full or empty.
Almost every time I fill the tank I fill it completely, and I always run it to about 1/8 tank.
I called it "low-pressure pump" because I thought there was a high-pressure pump somewhere near the fuel rail. I guess there's only one fuel pump in this pickup. Thanks for the correction.

Based on comments here I guess I'll just keep driving.

 

[Milkman5687]

My pump was making a louder than normal wine that I could hear in the cab. I had my suspicions about the fuel filter, that was it in my case. I let it sit all night and changed it the next morning and the pump to tank line section had spewing pressure from the blocked filter. Pump noise gone immediately.

 

[mikkelstuff]

Yes, change the filter first.

 

[Jack Schmidt]

Good tips about the fuel filter. Thanks.
It's only about 30k miles old but I will change it.

 

[Jack Schmidt]

Following up.
Replacing the fuel filter didn't help.
I replaced the fuel pump assembly just to be safe. The new pump is so quiet I hear it only during those first couple of seconds after turning on the ignition and before starting the engine, and if I have the door open.
The new pump was a huge relief during the long spring break road trip.

 

[Milkman5687]

Nice. Glad you found the issue, piece of mind and confidence in your ride is invaluable.