Buzzing sound

[dgn]

Alright guys, for some time now I've noticed that once I turn my VW off there is an audible sound I can only describe as a buzzing sound coming from the car, sounds like it's in the rear near the fuel tank. Today, it lasted for approximately 4 minutes after I turned the engine off and removed the key. Then what sounded like a "pop" sound and the noise was gone. Any ideas?

 

[CT8]

maybe a fuel pump relay? WAG

 

[bioburner]

I am thinking fuel vapor system

 

[SZR48207]

Originally Posted By: bioburner
I am thinking fuel vapor system


Same. My Tacoma will do random cycles at random times where I believe it is testing if the system to hold fuel vapors in is still functioning. I'll go into the garage at 2am and will hear it making a buzzing noise from the fuel tank area.

The other thing it does is it pulls a vacuum once I shut off the car. Sounds kind of like a turbo spinning down.

 

[dgn]

Cool, thanks for thr quick replies. The location makes since for something fuel related.

Follow up question: Is that something we would call normal or should I get it looked at by a pro?

 

[bioburner]

If it has a problem you will probably get a idiot light on the dash. Similar to loose fuel cap. My Xterra throws once in a while when the seal on the cap gets dirty.

 

[CR94]

Originally Posted By: dgn
... Follow up question: Is that something we would call normal or should I get it looked at by a pro?
My Toyota normally does the same thing Reddy45 described with his Toyota, 5 hours after shutdown. I'd read about it, but never actually heard it until this Tuesday. VW might do something similar.

 

[FordBroncoVWJeta]

My Jetta does it too! Best answer I found was there is a vacuum pump pressurizing the tank. It measures how long the tank is pressurized so it can say if there a leak somewhere.