Fuel Pump Whining?

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born2Run83

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During Engine idle, between the cab and bed (from the top) I can hear a whining sound. It's loud enough to hear from about 10ft away. I have a video of it for the audio but the site doesn’t allow video uploads.
I have a 5.3L LM7 with external fuel pump system mounted to the inner frame. Walbro 250LPH with inline filters. Fwd of that is the Aeromotive fuel regulator. Gas tank and sending unit are the same/original as when I bought the truck about two years ago. I'm not sure if this is the fuel pump making this sound. It just started doing this but last weekend left me stranded. truck would not start- only turned over. Sounded like it was out of fuel but I had 3/4 tank at the time. I sprayed starting fluid in the intake and it's been doing fine since.. Anyone ever experience this? TIA
 
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SirRobyn0

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During Engine idle, between the cab and bed (from the top) I can hear a whining sound. It's loud enough to hear from about 10ft away. I have a video of it for the audio but the site doesn’t allow video uploads.
I have a 5.3L LM7 with external fuel pump system mounted to the inner frame. Walbro 250LPH with inline filters. Fwd of that is the Aeromotive fuel regulator. Gas tank and sending unit are the same/original as when I bought the truck about two years ago. I'm not sure if this is the fuel pump making this sound. It just started doing this but last weekend left me stranded. truck would not start- only turned over. Sounded like it was out of fuel but I had 3/4 tank at the time. I sprayed starting fluid in the intake and it's been doing fine since.. Anyone ever experience this? TIA
It's easy to get a video on the site. Upload it to youtube and link it to the thread. It's always helpful if we can hear the noise, otherwise all we can do is guess.
 

Bextreme04

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During Engine idle, between the cab and bed (from the top) I can hear a whining sound. It's loud enough to hear from about 10ft away. I have a video of it for the audio but the site doesn’t allow video uploads.
I have a 5.3L LM7 with external fuel pump system mounted to the inner frame. Walbro 250LPH with inline filters. Fwd of that is the Aeromotive fuel regulator. Gas tank and sending unit are the same/original as when I bought the truck about two years ago. I'm not sure if this is the fuel pump making this sound. It just started doing this but last weekend left me stranded. truck would not start- only turned over. Sounded like it was out of fuel but I had 3/4 tank at the time. I sprayed starting fluid in the intake and it's been doing fine since.. Anyone ever experience this? TIA
I'd say its probably a 99% chance that your pump has gone toes up from heat and being mounted externally where it is having to pull up hill. Get yourself an EFI sending unit and an EP381 pump so that you don't keep having this problem.
 

born2Run83

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5.3L LM7
During Engine idle, between the cab and bed (from the top) I can hear a whining sound. It's loud enough to hear from about 10ft away. I have a video of it for the audio but the site doesn’t allow video uploads.
I have a 5.3L LM7 with external fuel pump system mounted to the inner frame. Walbro 250LPH with inline filters. Fwd of that is the Aeromotive fuel regulator. Gas tank and sending unit are the same/original as when I bought the truck about two years ago. I'm not sure if this is the fuel pump making this sound. It just started doing this but last weekend left me stranded. truck would not start- only turned over. Sounded like it was out of fuel but I had 3/4 tank at the time. I sprayed starting fluid in the intake and it's been doing fine since.. Anyone ever experience this? TIA
xc_hide_links_from_guests_guests_error_hide_media

Link attached for video/audio
 

born2Run83

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It's easy to get a video on the site. Upload it to youtube and link it to the thread. It's always helpful if we can hear the noise, otherwise all we can do is guess.
Thank you/ just uploaded it
 

nvrenuf

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I agree with @Bextreme04, the pump is probably dying.

99% of fuel pumps are “pushers” that are designed to start wet/primed. Since you’re using a stock tank set up it certainly, at least on occasion, starts dry which will eventually kill it.
 

born2Run83

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Thank you all for the quick feedback and insights here.
 

Ricko1966

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If you dont go with an intank pump,at least make sure your pump is mounted as close to the tank as possible,and below fuel level,other wise the pump is working harder and will fail sooner..
 

born2Run83

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I found that when I disconnect the return line from the regulator (Dump the fuel into a pan), the pump does not whine.
Tank is original, I have the filler neck connected to the tank with rubber hose, and rubber vent hose connected from the side of the filler neck to the tank as well.
Would the return line have an internal clog? Could I disconnect and blow Air through it? Or would if be something inside the tank?
 

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That may be due to the charcoal cannister.
 

Hunter79764

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I found that when I disconnect the return line from the regulator (Dump the fuel into a pan), the pump does not whine.
Tank is original, I have the filler neck connected to the tank with rubber hose, and rubber vent hose connected from the side of the filler neck to the tank as well.
Would the return line have an internal clog? Could I disconnect and blow Air through it? Or would if be something inside the tank?
Remove your cap, blow air into the return line, and see what happens. If you have a return line clog, your pump will be working much harder. Fuel pressure would go up, but your ECM might adjust for it easily and not throw a code. Try the return line purge and see what that does, but if your fuel trims are way out of whack or you read high fuel pressure at the rail, that might confirm it as well.
Note, if your return is plugged that doesn't necessarily mean your fuel pump is still good. All the above advice is still good for the "right" way to do it, and fighting against a plugged return can put a lot of wear and tear on a pump in a short period of time.
 

born2Run83

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West Texas
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Justin
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1983
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GMC - C1500
Engine Size
5.3L LM7
It's easy to get a video on the site. Upload it to youtube and link it to the thread. It's always helpful if we can hear the noise, otherwise all we can do is guess.
Remove your cap, blow air into the return line, and see what happens. If you have a return line clog, your pump will be working much harder. Fuel pressure would go up, but your ECM might adjust for it easily and not throw a code. Try the return line purge and see what that does, but if your fuel trims are way out of whack or you read high fuel pressure at the rail, that might confirm it as well.
Note, if your return is plugged that doesn't necessarily mean your fuel pump is still good. All the above advice is still good for the "right" way to do it, and fighting against a plugged return can put a lot of wear and tear on a pump in a short period of time.
Prior to reading your post, I did this but did not have the fuel filler cap off. I blew air through the return line from the tank side. Reconnected everything, and the pump still whines.

On the top/fuel sending unit (Pain fuel supply line, Return line, and open port (uncapped). is how it is set up and was originally for LS swap.
 

KnuckleBuster

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Noise by itself is not necessarily a problem. Electric pumps whine, some worse than others. If frame mounted, it may help if the pump is isolated with rubber bushings. If it still seems excessive to you, check the pump output (pressure and volume). A new fuel filter will sometimes alleviate the noise. Was the pump running (whining) when the engine wouldn't start?
 

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