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  1. #1
    Active Member Two Rings
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    Nov 03 2010
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    Edmonton, AB

    Strong Gas Smell Inside Car

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    Hi Guys,

    New problem just developed with the cold weather.

    2001 Audi Allroad, Tip Car

    When you let the car warm up in the morning and it's below -20C outside the cabin fills with a very strong gas odor. Once you start driving, it clears out.

    Where should I start looking? Anything common to check? I have only had the car for about a month now, so it's tough to give a bunch of different scenarios. Both times so far the car has been snow covered. Next time I will try making sure HVAC intakes are clear of snow. Also going to check rear hatch door and make sure it's closed properly.

    Thanks for any help,
    Steve

  2. #2
    Veteran Member Three Rings ben916's Avatar
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    Feb 02 2010
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    54393
    My Garage
    2012 CR-V (sipping gas while I gulp it)
    Location
    Seattle, WA

    Quote Originally Posted by wanarace View Post
    Hi Guys,

    New problem just developed with the cold weather.

    2001 Audi Allroad, Tip Car

    When you let the car warm up in the morning and it's below -20C outside the cabin fills with a very strong gas odor. Once you start driving, it clears out.

    Where should I start looking? Anything common to check? I have only had the car for about a month now, so it's tough to give a bunch of different scenarios. Both times so far the car has been snow covered. Next time I will try making sure HVAC intakes are clear of snow. Also going to check rear hatch door and make sure it's closed properly.

    Thanks for any help,
    Steve
    Well the C5 RS6 roll-over check valve for the gas tank had a recall on them about 2-3 years ago, IIRC. This did cause a couple of owners to have the fuel tank, which was leaking/cracked, to have them replaced under the recall.
    There were some photos on RS6.com about cracks in the fuel sending unit (i think, sorry I am unable to remember exactly what it was) from over filling?
    Not sure this helps...

    Is the smell from inside the car OR is it in the engine compartment and being pumped into the passenger compartment?

  3. #3
    Veteran Member Three Rings PaperToast's Avatar
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    Apr 29 2009
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    Quadzilla
    Location
    Longmont, CO

    when i start my ar up in the morning the exhaust has a strong fuel smell but goes away once its warmed up
    this is normal because the ecu is trying to get everything going by making the mixture richer than normal
    once the engine reaches temp, then it leans it back to normal
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  4. #4
    Senior Member Two Rings
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    1999 VW Jetta TDI 48MPG!, 1998 F150
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    New Jersey


    Sit Down, take a look at it, take it apart, and FIX it!

  5. #5
    Active Member Two Rings
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    Nov 03 2010
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    66542
    Location
    Edmonton, AB

    Thanks for the replies.

    The smell is inside the passenger compartment. Honestly it smells like I have a gas can sitting in the back. I believe the car has had the gas tank replaced under warranty, I will have to check the service history again. Also, when the car sits in the garage, there is no smell in the garage. The problem started happening once temperature dropped this week, below -20C, and the car has been sitting outside overnight. Normally the car sits in an unheated garage (5C), when you start it then, no problems.

    I will check out the exhaust and see if it's getting in through the back hatch, maybe there is some snow or ice getting in the seal, creating a leak. Also I will try putting it on "recycle cabin air" next time it heats up in the morning.

    Thank you,
    Steve

  6. #6
    Veteran Member Four Rings Vinchenzo51's Avatar
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    Jan 31 2010
    AZ Member #
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    S-Line A6
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    East Haven, CT
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    Let us know what you find

    But be careful, you don't want to mess around inside the car too long with gas fumes... Not gonna end well

  7. #7
    Veteran Member Three Rings ChescoS6's Avatar
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    Jan 13 2007
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    My Garage
    2012 Golf TDI 2003 Ducati ST4s ABS 2007 Ducati Monster S2R
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    Quote Originally Posted by PaperToast View Post
    when i start my ar up in the morning the exhaust has a strong fuel smell but goes away once its warmed up
    this is normal because the ecu is trying to get everything going by making the mixture richer than normal
    once the engine reaches temp, then it leans it back to normal
    Yep, I agree, mine does the same thing.
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  8. #8
    Active Member Two Rings
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    Nov 03 2010
    AZ Member #
    66542
    Location
    Edmonton, AB

    I will be safe, maybe bring the CO alarm from the garage in the car with me. Maybe a good way to see if exhaust is getting into the car.

  9. #9
    Active Member Two Rings
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    Nov 03 2010
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    Edmonton, AB

    The gas smell is coming from under the hood and getting sucked in to the cabin. I believe the problem had more to do with the vents being covered with snow, then the cold weather.

    Also, the exhaust smells pretty standard.

    Now, for a strong gas odor coming from under the hood. Where should I be looking first? This is still cold weather related, I believe, as the car can sit in the garage all night, and there be no smell of gas.

    I am going to look into the vented oil cap update as well.

    Thanks,
    Steve

  10. #10
    Veteran Member Three Rings ben916's Avatar
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    Feb 02 2010
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    2012 CR-V (sipping gas while I gulp it)
    Location
    Seattle, WA

    Quote Originally Posted by wanarace View Post
    The gas smell is coming from under the hood and getting sucked in to the cabin. I believe the problem had more to do with the vents being covered with snow, then the cold weather.

    Also, the exhaust smells pretty standard.

    Now, for a strong gas odor coming from under the hood. Where should I be looking first? This is still cold weather related, I believe, as the car can sit in the garage all night, and there be no smell of gas.

    I am going to look into the vented oil cap update as well.

    Thanks,
    Steve
    Steve,

    Start with the fuel rail as with colder temps, metal and other materials tend to shrink which might be enough for fuel vapors to escape and then, once warmed up, the metal/bits expand to seal the gap(s).
    This is, to me, rather alarming. Either bad design, loose connection, or item(s) not put back together properly.

    One spark and it is all over.

  11. #11
    Active Member Two Rings
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    Nov 03 2010
    AZ Member #
    66542
    Location
    Edmonton, AB

    I will yank the engine covers look around. Fuel regulators tend to be a problem in other cars, so I will start checking everything from supply line to return line, and all the pieces between.

    Thanks,
    Steve

  12. #12
    Senior Member Two Rings
    Join Date
    Oct 26 2005
    AZ Member #
    8517
    Location
    St Paul

    From my local forum:

    Models Affected: S4 2.7T, A6 2.7T, allroad 2.7T (these added for search hits in future)

    As the 2.7T engines age, a common issue that pops up is a small leak where the fuel supply line connects to the fuel rail. The leak is typically either at the actual fitting to fuel rail connection or where the rubber hose attaches to the fitting. Typically the leak first occurs only at very cold temps, and the symptom will be the smell of fuel in the cabin shortly after the car is started up.

    Because the fuel is leaking onto the engine above the exhaust manifolds, I recommend taking care of the issue ASAP. You can imagine what might happen if the fuel leaked out at a rate where it was able to make it to the hot exhaust manifolds before it evaporates.

    If the fitting is leaking, I recommend buying a NEW fuel supply line (part number 4B0201541C ). The hose fitting at the fuel rail end is a ball type seat. When tightened onto the fuel rail, it deforms slightly creating a seal. (kind of like a crush washer). Because of this, simply tightening the old fitting tighter on the fuel rail frequently results in continued leaking days later. Replacing with a used line is not recommended due to the same reason. Again, it *can* work, but this isn't something I'd recommend playing around with.

    Buying the supply line locally at the dealer will cost just over $70 with tax, and you can find them online for around $55 shipped. If the car is being driven, I highly recommend buying it locally and fixing it asap, as saving $15-$20 isn't worth the risk of fuel leaking in your engine bay. The best/safest advice is don't drive the car with fuel leaking at all.

    In order to change this line, you will need to depressurize the fuel rail before disconnecting the supply line (so you don't spray fuel all over the engine bay / your face / your garage). To do this, remove the fuel pump fuse and start the car. The car will die after a few seconds if you pulled the right fuse. Start the car up again, and let it die. Continue until it won't start anymore.
    If you aren't able to locate the fuel pump fuse, please stop and schedule some time at a good shop to have this done.

    Also worth mentioning to do this in a well ventilated area, as there will be fuel fumes present when changing the line.

    When you disconnect the fuel supply line, there will still be some pressure in the line, so make sure to wrap the connection with rag/towel before loosening, and go slow to control rate at which the remaining pressure can be relieved.

    You may have a "fun" time getting the clip off the other end of the fuel hose where it attaches to the hard line near the firewall. It's important when attaching the new hose that this connection is secure. Failure to secure this well can result in the hose popping off from the fuel pressure and dousing your engine bay with raw fuel.. near the turbo and exhaust. I like non-perforated rolled edge screw clamps where turning the screw has good resistance so it does not back itself out. Feel free to toss two clamps at that connection right next to each other.

    When putting the new hose on, attach the fuel rail end first. This prevents the hose from twisting the wrong way if you attach the other end first. If the hose is twisted, it will have a natural tendency to back the fitting out. Do not over-torque the 17mm nut, but it does need to be nice and secure. I don't know what the official torque spec is for this connector, but I'll try and find out and include in this post.

    Hope this helps someone when they run into this issue!
    Note the line/connection being referenced here is the one that goes over the airbox. Hope it helps!

  13. #13
    Active Member Two Rings
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    Nov 03 2010
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    Edmonton, AB

    Thanks Rageman2, everything always helps. I will check it out.

    Steve

  14. #14
    Active Member Two Rings
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    Nov 03 2010
    AZ Member #
    66542
    Location
    Edmonton, AB

    Took covers off today and had a look. I can see the line and connection mentioned in Rageman2's post. It looks like there maybe be a slight leak in that vicinity, but it's very hard to tell. The fitting was bone dry, but the injector wiring near looked a bit wet. Could also be from the injector. Problem is, I could not get it to leak in the garage, must be too warm. I am leaving the covers off, so next time it's -25C outside I can have someone take a look while I start it.

    Thanks,
    Steve

  15. #15
    Active Member Two Rings
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    Nov 03 2010
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    Edmonton, AB

    Back from the dead.

    Found the leak. My car leaks at the injectors or the it is the actual injectors. Last year I swapped out the o-rings and all was good until this year. -30C this year caused massive leaking. I am talking half a liter in 30s kind of leak. I swapped out the o-rings again. Same problem.

    Did some research, and it appears fuel injectors o-rings are made from Viton. Viton is good to about -10C. Below that it is pretty useless. I sourced some silicone o-rings. Today it was -23C, not -30C. There was still some leaking at the injectors but not as bad. Now I can't tell if it was because of the seals, or the injectors themselves may leak less at -23C then -30C

    I am going to try source some different injectors and see what happens.

    I posted this to give anyone a heads ups who may have similar problems. If you have a fuel smell when starting the car cold, I would suggest taking a look at the injectors and o-rings.

    Steve

  16. #16
    Veteran Member Four Rings
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    Apr 18 2007
    AZ Member #
    17386
    Location
    ny
    Items for Sale

    I have this problem with the high pressure fuel line that feeds the fuel rail, it leaked a bit last week when it was super cold but then stopped.
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  17. #17
    Established Member Two Rings N'syncro's Avatar
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    Feb 04 2010
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    My Garage
    '05 allroad, '77 Westfalia
    Location
    Edmonton, AB
    Items for Sale

    Keep us posted. I have the same problem in the extreme cold (-25C and colder)

  18. #18
    Established Member Two Rings
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    Feb 09 2011
    AZ Member #
    70692
    Location
    Iowa

    +1

    2.7t

    Gas smell happens until engine comes to temp anywhere below 10F, worse when colder. So far I see zero leaks on motor or ground.

  19. #19
    Established Member Two Rings
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    Jun 15 2010
    AZ Member #
    60307
    My Garage
    2000 2.7t 6 spd, 2.9tt volvo XC90, B6 audi A4 3.0, 2004 RS6,
    Location
    edmonton

    its your injectors that are leaking. i had this exact same problem. i changed the orings a million times, each time a different way and also tried different oring material. its the injector bodies that are leaking. it leaks between the metal body and the plastic connector. mine actually leaked at the pins on the electrical connectors, just pul your connectors off and see if there is fuel there. its just fatigue of the material and the extreme temps. i changed all of mine with new ones and problem gone. car ran nicer too, fresh injectors at 150k miles doesnt hurt anyway.
    Quote Originally Posted by wanarace View Post
    Back from the dead.

    Found the leak. My car leaks at the injectors or the it is the actual injectors. Last year I swapped out the o-rings and all was good until this year. -30C this year caused massive leaking. I am talking half a liter in 30s kind of leak. I swapped out the o-rings again. Same problem.

    Did some research, and it appears fuel injectors o-rings are made from Viton. Viton is good to about -10C. Below that it is pretty useless. I sourced some silicone o-rings. Today it was -23C, not -30C. There was still some leaking at the injectors but not as bad. Now I can't tell if it was because of the seals, or the injectors themselves may leak less at -23C then -30C

    I am going to try source some different injectors and see what happens.

    I posted this to give anyone a heads ups who may have similar problems. If you have a fuel smell when starting the car cold, I would suggest taking a look at the injectors and o-rings.

    Steve
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  20. #20
    Established Member Two Rings rogersb6's Avatar
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    Feb 14 2012
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    88187
    Location
    Bellingham

    B I had something interesting happen in my AR today: the flare fitting for the pressurized line into fuel rails began leaking when we hit the high 20s (F) this year. I snugged it up with the 14 and 17mm wrenches and all was good. Until we hit 20-F today and there was a considerable leak coming from that fitting.

    I'm just digging into things, but I'm going to clean the fitting out and reassemble. Hopefully it will quit once its clean and assembled. Until then: wrenches stay in the car

  21. #21
    Veteran Member Three Rings 4rings2turbos's Avatar
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    Aug 04 2009
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    Glen Ellyn, IL

    OEM+ work in progress allroad

  22. #22
    Established Member Two Rings rogersb6's Avatar
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    Bellingham

    Oh nice! Thank you for that. I just started the car in 19-degrees and the damn thing is still leaking. Replacement it will be! Annoying that a crimped flare fitting on fuel line is $85 though.

  23. #23
    Veteran Member Three Rings 4rings2turbos's Avatar
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    No problem!

    Yeah :/ one of the slightly pricier parts than what you'd guess.
    OEM+ work in progress allroad



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