In the morning when I start up my car after the secondary pump is done and i'm just sittin there, I hear a faint knock coming from the rear of my car. It sounds like a tied-up midget is trying to break out of my trunk or something. It doesnt do it constantly but maybe 3 times a minute or so till I start driving. Does anybody have an idea of what that might be?

 

do you park your car in the garage or outside? maybe the mobs decided to dump a tied-up midget in your trunk over night.

On a serious note, maybe it's the fuel pump?

 

sounds like the vac vent on the fuel tank so normal

 

Would it make an electronic noise at all?

 

When a friend of mine had the same knocking noise caused by the vacuum vent on his Mazda fuel tank, he took it to a meachanic... I did not know what the mechanic had done but the vacuum vent noise was really reduced to a lower tone... I'l to talk to him this coming weekend...

 

I read that the quattros have two gas tanks and have a pump that tries to level them out. Perhaps that is it.

 

Where did you read that? I see one tank...

 

Quattro fuel tank is divided in two sections. If you looked a little more you would see two sending units on the quattro and only one on the fronth wheel drive.

 

The quattro fuel tank is not divided. It's shaped that way to clear the driveshaft. It's also sloped to keep the fuel closest to the pump.
There is only one fuel sender, the other sender looking unit is the fuel return. Yes, the quattro tank does differ from the fwd tank... because the fwd TT's don't have a rear differential to get in the way.

 

You are arguing symantics. The sound he is here is the pump leveling off the two sections of the fuel tank.