2002 GMC Sierra fuel pump

2002 GMC SIERRA
110,000 MILES • V8 • 4WD • AUTOMATIC
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JIMMOONANDSUE2
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It sounds as though the electric fuel pump is running continiously. Its a very high pitched whine or whistle type noise. I feel sure it is comming from the fuel pump. But, why would the pump run continiously? I have owned this truck for 4 years and it has always done this but it seems to be getting louder.

Thanks You,
Susan
Oct 12, 2009 at 10:49 AM
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OBXAUTOMEDIC
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Hi Susan,

Were does it sound like it is coming from, the front of the vehicle or the rear.

Also when you say that the Fuel Pump runs continuously, do you mean when the vehicle is running or whether the vehicle is running or not. When the vehicle is running the Fuel Pump should run continuously.
Oct 12, 2009 at 6:37 PM
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JIMMOONANDSUE2
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It makes the sound when the truck is running. The sound comes from the side of the truck where the gas cap is . There is a loud hissing sound if a stand by the passenger rear fender well. Back pressure from the fuel line?
Oct 16, 2009 at 2:25 PM
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OBXAUTOMEDIC
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Hi, Sorry for delay in getting back to you...


A hissing sound is usually and indication of a Vacuum Leak or possibly and Exhaust Leak.

The fuel return shouldn't have enough pressure to cause any noise.

Does it sound louder when you remove the gas cap?

If so it is most likely the fuel pump.


.
Oct 18, 2009 at 2:15 PM
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