Good Morning, All:

The Patient: 1999.5 A4 2.8, stick.
The Problem: A few months back, whenever the car was started after sitting overnight, a soft gurgling noise starting coming from the passenger rear of the car for a second, It's been getting progressively louder and longer as the fall has set in (we're in New Jersey). I know that it's the fuel pump sitting back there, and not much else is in the neighborhood, so I figure it's gotta be him. The car has no driveability problems, starts right up, does not sound like it's starving for fuel at any point, so I don't think the pump isn't working, it's just that damned gurgle getting louder that's bugging me.

So, my question: Is the pump on its way out? Or is some check valve that's supposed to keep the system solid with gas failing, allowing the return loop to drain back into the gas tank overnight? If that's the case, where is said check valve?


Thanks!
-Red

 

Mine's been doing the same thing, though after 5 months of doing it and no major problems arising, I more or less just learned to ignore it. But I agree, it did get annoying for a while, but it's one of those things I found easy to tune out after a while. I am interested in knowing if it is a lurking problem that needs resolved though, so techies: any ideas?

 

This is a redundant thread: https://www.audiforums.com/forum/sho...uel+pump+noise

But no one has given a good technical reason why some cars make this noise and others do not. Anyone?

 

Aw, crap. I misread that thread when I did my search. I though it was from earlier, hence my starting a new thread. Sorry 'bout that.

But yes, no one has a good technical reason why it's happeneing, and it seems like there are more than a few of us with this particular problem. There has to be a good reason for it somewhere.

My guess is that the gurgle are the fuel lines or pump being repressurized, but why would they drain in the first place? Anyone have a service manual with a breakdown of that end of the fuel system?

-Red

 

i believe the pump itself has a check valve to prevent the fuel from flowing backwards thru it. im only guessing but you could have some air in the fuel filter or something? when you turn the ignition to "on" the fuel pump pressurizes the line even before the engine starts. it could be the fuel return line somehow is above the fuel level in the tank and your hearing it splash back down into the gasoline. does it happen all the time regardless of how full the tank is? try changing your fuel filter, it couldnt hurt and if you still have the stock filter it would be worth doing anyway. remember to change the 4 copper washers when you change the filter too.

 

Mine has made that noise the day I got it and so has my friends. I thought i read online somewhere about the quattro tank design being kind of goofy so that when the pump gained pressure, it had to pump it up and over before heading to the engine or something like that so it made a noise...

 

yea mine makes that noise all the time...

 

I changed my filter a few months ago and it continues to make the noise.

 

This link addresses the same noise:
http://www.audizine.com/forum/showth...oise+fuel+pump

"Its probably the smaller pump that pumps the fuel over the hump in the tank that you can hear." - What is the "smaller pump"? could it be the culprate?

 

BUMP

Does anyone actually KNOW what makes this noise? and know why only some cars make it?