Sound from gas tank after shutoff?

ferocity02 · 09-10-2014, 03:57 PM

Yesterday I noticed that after I've shut off the car and even locked it, there is a steady sound from the back of the car underneath on the left-ish side. The sound resembles a fluid pump and is not very loud. I didn't time it but it will stay on for at least a couple minutes. I drive about 20 miles to work. Anyone know what this is? Fuel pump?

Car in sig, no SES light.

Snypa · 09-10-2014, 04:40 PM

I know the fuel pump primes when you unlock or attempt to open the trunk even when its locked.

ferocity02 · 09-10-2014, 05:12 PM

Quote:

Originally Posted by Snypa

I know the fuel pump primes when you unlock or attempt to open the trunk even when its locked.

Yep I hear that too when unlocking, but it only lasts a couple seconds. This sound is different and lasts at least a minute.

thomas88162 · 09-10-2014, 05:18 PM

This is common. I'm not entirely sure what it is, but I have heard that the purpose is to balance the fuel quantity between the two cells which our fuel tanks are made of.

ferocity02 · 09-10-2014, 05:42 PM

Quote:

Originally Posted by thomas88162

This is common. I'm not entirely sure what it is, but I have heard that the purpose is to balance the fuel quantity between the two cells which our fuel tanks are made of.

Very interesting, didn't know about that. I found a video of the noise on youtube...

nitehawk · 09-10-2014, 06:39 PM

I get the same noise and have wondered what this was too....

09-10-2014, 03:57 PM	#1
ferocity02 Colonel 564 Rep 2,085 Posts Drives: 2013 135is Join Date: May 2014 Location: USA iTrader: (8)	Sound from gas tank after shutoff? Yesterday I noticed that after I've shut off the car and even locked it, there is a steady sound from the back of the car underneath on the left-ish side. The sound resembles a fluid pump and is not very loud. I didn't time it but it will stay on for at least a couple minutes. I drive about 20 miles to work. Anyone know what this is? Fuel pump? Car in sig, no SES light. __________________ 2013 135is DCT Carbon Black Metallic
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09-10-2014, 04:40 PM	#2
Snypa Captain 40 Rep 656 Posts Drives: Like a mahdman ! Join Date: May 2013 Location: I-75 iTrader: (3)	I know the fuel pump primes when you unlock or attempt to open the trunk even when its locked. __________________ SUPER SLOW E90
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09-10-2014, 05:18 PM	#4
thomas88162 Lieutenant 19 Rep 595 Posts Drives: E92 328i Join Date: Jun 2013 Location: Clinton, IN iTrader: (0)	This is common. I'm not entirely sure what it is, but I have heard that the purpose is to balance the fuel quantity between the two cells which our fuel tanks are made of.
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09-10-2014, 06:39 PM	#6
nitehawk Lieutenant Colonel 111 Rep 1,909 Posts Drives: e92 335i 6MT Join Date: May 2011 Location: Toronto iTrader: (15) Garage List E92 BMW 335i [9.00] E92 BMW 335i \| Retired [10.00]	I get the same noise and have wondered what this was too....
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