# Knocking/Tapping coming from the rear of my 225Q



## SoloGLI (Jan 20, 2005)

The sound is more of a tapping that I hear when the car is stopped, or immediately after I turn the car off. I was reading some old threads, and the only answer that I could come up with is that there is something in the gas tank that levels the fuel? I've never heard of this so I have no idea how accurate that is. Anyone have any ideas what else it might be??


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## SoloGLI (Jan 20, 2005)

*FV-QR*

Anyone?


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## SoloGLI (Jan 20, 2005)

*FV-BumpIt(1260259461625)*

Really... no one has ANY ideas??? I always thought there were some knowledgeable people around here


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## darrenbyrnes (Jan 4, 2005)

*Re: FV-BumpIt(1260259461625) (SoloGLI)*


_Quote, originally posted by *SoloGLI* »_Really... no one has ANY ideas??? I always thought there were some knowledgeable people around here

I think you have a midget trapped in your gas tank who is trying to escape.
/I don't think anyone who has read this thread has ever experienced the tapping as you describe, thus the lack of responses. Plus a lot of people have moved on to other forums...


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## Minibabe (Jul 5, 2006)

*Re: FV-BumpIt(1260259461625) (darrenbyrnes)*

I have the same problem......I have had it for 2 years now and I have no idea what it could be. I will be watching this topic though because I would love to get to the bottom of this and find out what actually is wrong. http://****************.com/smile/emthup.gif 
I always assumed that it was a gremlin in the gas tank though


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## Corradokid135 (Apr 10, 2006)

*Re: FV-BumpIt(1260259461625) (Minibabe)*

I have the same sound in my 180Q. Have yet to figure it out....


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## DjSticky (Apr 6, 2009)

*Re: FV-BumpIt(1260259461625) (Corradokid135)*

Now that others have come forward I am slightly less ashamed to admit that my car is making a noise that I have not identified and now ignore.
It only happens shortly after starting and it is more feverish after I have taken a corner.
I though it was a my diff at first but closer inspection told me it was fine. 
Are their aliens in my gas tank trying to make it level? This sounds plausable because it is faster after cornering (fuel sloshing around). I need to go fill up, do a cold start and see if I hear anything.


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## l88m22vette (Mar 2, 2006)

*Re: FV-BumpIt(1260259461625) (darrenbyrnes)*


_Quote, originally posted by *darrenbyrnes* »_Plus a lot of people have moved on to other forums...

Which ones? I go to AudiFreaks a lot as well, but compared to other TT sites this is the best - its nice not to have to answer n00b questions every day (see AudiWorld)


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## darrenbyrnes (Jan 4, 2005)

A bunch moved from Audiworld to Quattroworld.
Just sayin'.


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## Minibabe (Jul 5, 2006)

*Re: (darrenbyrnes)*

quattroworld FTW








I http://****************.com/smile/emlove.gif that website


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## sims159915 (Jan 24, 2005)

*FV-QR*

vortex to BS
quattroworld for real info


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## l88m22vette (Mar 2, 2006)

*Re: FV-QR (sims159915)*

Well, I checked out QW, it has the same awful format as AudiWorld used to, and I can't imagine that there is any parallel to Vortex's 1.8T forum...no thanks, I'll keep racking up my post count here


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## EXPELLED (Jun 24, 2008)

same problem here


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## artur vel 2 hoot (Nov 25, 2006)

*Re: (EXPELLED)*

Because tank is '' U '' shaped ( only quattro ) thear is secondary fuel pump to make fuel lewel even betven left and right site of tank doing so it is create that sound ...


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## darrenbyrnes (Jan 4, 2005)

*Re: FV-QR (l88m22vette)*


_Quote, originally posted by *l88m22vette* »_Well, I checked out QW, it has the same awful format as AudiWorld used to, and I can't imagine that there is any parallel to Vortex's 1.8T forum...no thanks, I'll keep racking up my post count here









I visit all of them but have found the Vortex to be the most helpful when it comes to my cars - the TT and Rado before that.


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## SoloGLI (Jan 20, 2005)

Can you guys take the chatter about the different forums to PM?


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## Doooglasss (Aug 28, 2009)

*Re: (SoloGLI)*

The EVAP system is located in the back of your car in various places. Part of the ventilation and some mechanical valves are right in the rear passenger fender attached to the fuel fillup pipe thing. I've had my car apart back there. I've heard this noise (I believe) and I think it's 100% normal.
The other part of EVAP in the rear is in the spare tire center popup thing.


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## SoloGLI (Jan 20, 2005)

Thats interesting, thanks Doug. At least I know I'm not alone with this, so I don't feel too worried about it now.


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## redTTalms (Apr 8, 2008)

*Re: (SoloGLI)*

ive been hearing that knocking noise for a while in my car as well


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## RonN (Feb 15, 2001)

*Re: (redTTalms)*

Could be a combination of sounds you're hearing between the suspension and gas tank. The MKIV R32 is horrible at the gas tank sound. My TT just started making the gas tank sound in the past few months but I only notive it when under half tank.


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## TToxic (Nov 15, 2008)

*Re: (DougLoBue)*


_Quote, originally posted by *DougLoBue* »_The EVAP system is located in the back of your car in various places. Part of the ventilation and some mechanical valves are right in the rear passenger fender attached to the fuel fillup pipe thing. I've had my car apart back there. I've heard this noise (I believe) and I think it's 100% normal.
The other part of EVAP in the rear is in the spare tire center popup thing.

The rear evap canister purge valve releasing tank pressure is exactly what causes this noise. Not the valve itself but the fuel tank flexing from pressure relief. I had this noise since TT was new once I deleted all evap. including canister no noise ever again, my tank vents to atmosphere - no pressure build up, no noise.


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## Corradokid135 (Apr 10, 2006)

*Re: (TToxic)*

http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif


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## DjSticky (Apr 6, 2009)

*Re: (TToxic)*

Great! Thanks all! http://****************.com/smile/emthup.gif


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## darrenbyrnes (Jan 4, 2005)

*Re: (SoloGLI)*


_Quote, originally posted by *SoloGLI* »_Can you guys take the chatter about the different forums to PM?

And yet we were extolling the virtues of the Vortex - especially the TT and Rado forums.

And it's good to know about that rattle.
http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif


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## RonN (Feb 15, 2001)

*Re: (TToxic)*


_Quote, originally posted by *TToxic* »_
The rear evap canister purge valve releasing tank pressure is exactly what causes this noise. Not the valve itself but the fuel tank flexing from pressure relief. I had this noise since TT was new once I deleted all evap. including canister no noise ever again, my tank vents to atmosphere - no pressure build up, no noise.

So help me out here... Are there any negative side effects to having this on a daily driver? Is redundancy built into the vent to atmosphere to prefent fuel from leaking out? 
I really like the sound of this but am struggling with a visual because I'm not really familiar with the layout of our fuel tanks.


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## SoloGLI (Jan 20, 2005)

The evap system is for emissions laws. It really doesn't have any benefit being on the car, and you won't see any adverse effects from removing it. At least on my mk4 1.8t, I never had any issues after removing it.


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## RonN (Feb 15, 2001)

*Re: (SoloGLI)*

Thx http://****************.com/smile/emthup.gif


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## winTTer (Jul 29, 2004)

*Re: (RonN)*

sounds like we've found a little extra weight reduction thru this thread. http://****************.com/smile/emthup.gif 
my tt makes the same sound btw


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## jay2gas (Nov 17, 2009)

i think its the fuel pump.


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## storx (Dec 6, 2006)

this noise is the flexing of the fuel tanks when under pressure.. when you take off hard or go around a corner the fuel return causes pressure in the tank and your lift pump is suppose to even out the 2 tanks and after a while it gets to were it still does its job but pressure builds up on the return side because of wear and tear and climate.. i noticed this once when i went for a ride in the TT after the new stroker setup.. and when i was checking fuel pressure it was pegged.. went to take the hose off to try using another gauge and fuel shot out the return side.. was really amazed that the car works this way so i took a look in the tank and ended up deleting alot of that stuff and just venting to atmosphere..


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