my car is about to die!

[nwe30]

My car has been making this weird "whirring" sound. I have a feeling it may be the fuel pump about to go out, but I am nowhere close to having the aptitude of car knowledge that everybody else here on r3v seems to have.
The sound has been present for awhile now but it was never as loud as it is now. I knew it was imminent that the sound would only get worse, but I don't know what to do! Is there a way I can test the vitality/ life span of my fuel pump? I have an extra fuel pump in my garage from the PO but I'm not entirely sure if that is even fully functional. ANY help would be greatly appreciated.

Thanks r3v!

My car is a non vanos m50 if that makes any difference....
Also, I only get about 240 miles to the tank (my car is a 1990 so it has a bigger fuel capacity compared to the early models too), could this be due in part to the fuel pump about to give out (if that's the culprit causing the "whirring" noise) ?
If a video is necessary for you to help me out here, I would gladly upload one onto youtube.

[nrubenstein]

Fuel pump is in the back of the car. Figure out where the noise is coming from.

[nwe30]

Fuel pump is in the back of the car. Figure out where the noise is coming from.

Yes, the noise is coming from the back end of the passenger side. I believe I know where the fuel pump is located, it's underneath the back seat on the passenger side. I would just like to know how to diagnose the problem.

[Van Westervelt]

The Bentley manual narrates how to do a flow test on your fuel pump. That will tell you if it is in good nic or not.

You listed your miles per tank, but everyone fills up at different levels. How many mpg are you getting? Cant really use that to pinpoint a faulty pump though.