question about a noise heard

i've had my wrx wagon for about 3 months now and i just noticed something today. i got home from work and shut off the car. I turned it back on to ACC and noticed a whine + smooth mechanical sound from the rear of 3-5s in duration. Is this an AWD thing?

jon

 

The fuel pump primes when the car is turned on. That would be my guess without hearing it.

The fuel pump is just behind the rear seat on the passengers side. It runs for about 3 sec whenever the key is moved to the on, but not start, position.

Hope this helps.

 

I've always wondered why this sound always came on, too. Clears up that question.

 

igofast, sounds like a pump. your description is accurate to my experience. tanks! i'm glad everybody can learn something from my noob of a question.

 

Definitely fuel pump...if you ever get a Walbro, it's even louder.

 

Werd, the Walbro screams like a banshee when the fuel tank is full, gets less as it nears empty. I can actually hear it over my car idling which is not always an easy accomplishment.