Hard to fill gas tank and knocking sound

[elipem01]

I recently purchased a 2005.5 A4 B7. I've been having problems filling it up with gas because it kicks the pump off every gallon or so. I've searched through the forum and found that it may be the charcoal canister or leak detection pump. I think I know how to troubleshoot it but I can't figure out how to get the hoses off to find out which one is the problem. It appears to be a ring that needs to twist or slide but I'm afraid I'm going to break it. Can someone explain how to get both of the hoses off to determine what the problem is? Also can they be cleaned out or do they need to be replaced? If they need replaced, where would be the best place to purchase? I also have a knocking sound that appears to be coming from the same place. It happens after the car is warmed up at idle and for about 20 seconds after I turn the car off. Are these problems related or two separate things that need to be checked out? Sorry for all the questions but I'm new to Audi and need some insight. Thanks.

[elipem01]

Anyone?

[Sreddington]

I have the exact same problem, 05.5 too.... please take a pic or something if you figure it out on what we have to replace. the knocking noise drives me crazy haha and not to mention taking 15 minutes sometimes to get 20 dollars of gas in the car!

[A4B7GA]

I had this same issue. Not sure if this is correct but basicaly my tech told me that one of my fule pumps had died and the other was working overtime to makeup for it causing some negative pressure in the tank and the knocking sound is the tank returning to its normal size...I thought this was complete BS...but after they replaced my entire fuel tank, two pumps, and the evap canister its all gone.
Now, I did also have the hard time filling my tank. Before the replaced everything, it happend at every station...now only at one.
so...thats what I know...oh yeah...I have a 5.5 also

[nferguson]

Mine did that exact same thing So I Just had the canisters replaced under warranty.

[adub]

When you go to put the gas in, turn the it upside down.

...seriously.

[00grand00]

When you go to put the gas in, turn the it upside down.

...seriously.

i have a 05.5 with the same issues. turning it upside down works for me every time!

[vbrad26]

haha definitely turning it upside down next time...

[Sreddington]

i have a 05.5 with the same issues. turning it upside down works for me every time!

yes turning it upside down works to fuel up. The more annoying part I would say is the clunking at idle sometimes and when the car turns off after a drive. So ultimately fuel pumps need to be replaced?

[vbrad26]

i have the hard to fill up issue...but not this clunking...

[jimrobbington]

Me, no clunking, but I can't fill the tank. I will pump it upside down next time.

[b7kevin]

wow. sounds like a pita, i would bring it to audi despite the cost to fix that

[adub]

Well I have owned three cars that have done this. My s4 does it too on occasion. I thinks it's called vapor lock- where air get in the tank and triggers the nozzle to shut off.

[jimrobbington]

It also seems to me like gas pumps have become much more sensitive to shut off, not just our cars...

[adub]

It also seems to me like gas pumps have become much more sensitive to shut off, not just our cars...

That too.

[elipem01]

Just tried filling upside down and it helped some but still kicked the pump off. I can't seem to get the large hose off the canister to check it. From what I understand, the ring slides toward the canister and the hose pulls out. I've pulled with everything I have and can't get the ring to budge. Not sure what I'm doing wrong. Was able to get the small hose off but that didn't help much.

[chrislane31]

I have had the problem filling up for a while and possibly the knocking sound and today the car died on the highway with a quarter tank left and will not restart. Ala got a cel yesterday so hopefully that is related and it is an easy fix. Anybody that had the fuel pumps and canisters replaced have any part numbers? Posing from the aide of the road waiting for a tow truck.

[jimrobbington]

I have had the problem filling up for a while and possibly the knocking sound and today the car died on the highway with a quarter tank left and will not restart. Ala got a cel yesterday so hopefully that is related and it is an easy fix. Anybody that had the fuel pumps and canisters replaced have any part numbers? Posing from the aide of the road waiting for a tow truck.

Fuck that sucks, chris. Not fun any time of the day, much less 5:30 am. Do you think it just stopped supplying fuel?

[chrislane31]

I dont know now. I added a gallon of fuel and it started but still had it towed to a shop and filled it up and it appears to be driving fine. I was not out of gas because the warning light had not come on yet. I got the P0089 and P0456 codes but the 0089 code can be for a ton of stuff. I think I am going to change the fuel filter and just drive it and not let it get below a quarter tank and see what happens.

[GDC]

I dont know now. I added a gallon of fuel and it started but still had it towed to a shop and filled it up and it appears to be driving fine. I was not out of gas because the warning light had not come on yet. I got the P0089 and P0456 codes but the 0089 code can be for a ton of stuff. I think I am going to change the fuel filter and just drive it and not let it get below a quarter tank and see what happens.

I had the same problem car died with about a quarter tank, they shop said it had physically ran out of gas and the fuel gauge was calibrated wrong from the dealership. They recalibrated it for me and it has been fine since. $200 tank of gas... Great...

[chrislane31]

Any idea how they recalibrated the fuel tank?

[A4B7GA]

So, my warranty expired last week of august and now the problem is back...dropped the car off and now they say they need to replace the fuel tank...again! They were "so kind" to offer to cover the parts but I need to pick up the 1K in labor....good thing I called AOA before I took it in...after the dealership called me, I called my SA with AOA right away and she asked " what would I like"....I responded that I shouldnt have to pay for anything. This car has had consistent problems with the fueling system and just because an arbitrary date passed....Im not even 65K miles...should I have to pay for anything with a consistent issue.

For those of you who have been having this trouble; I will be mentioning this forum and other 5.5's with the issue...if you want me to add your VIN/name on my next call...PM me.

[papadelogan]

I did not have a knocking sound, but mine was hard to fill. My issue was resolved by replacing the main charcoal canister under the rear of the car. There are a few threads that talk about it and give troubleshooting advice to analyze exactly what is causing your issue.

Here's a couple links for you:

http://www.audizine.com/forum/showth...nd-fuel-filter

http://www.audizine.com/forum/showth...?highlight=LDP - See post 5

Yes, most of the threads you find will be for a B6. Part #s may be off, but the systems are the same.

[jimrobbington]

I ended up having the knocking sound also, but only heard it after the car was shut off. Came to deduce that it was the n80 valve failed, and pressure was either expanding or imploding the gas tank. Replaced n80 and no more clanking. Still clicks off during fueling, but not as bad as before.

JR

[J.Owen]

I have both the knocking and the hard fill on my 05.5. I replaced the n80 valve not too long ago and it seemed to help out, but not cure the issues completely. Once my brothers S4 is off the lift I plan to check out my charcoal canister.

[plokm]

dont worry check this carbon canister diy out

http://www.audizine.com/forum/showth...lem?highlight=

[A4B7GA]

Update: My SA from my local Audi Dealership just called and first hit me up for a 10 on the service response...then stated that everything was covered and they are awaiting a complete fuel system (Tank, Pump, Valve...)
Score!

[Coupee36]

I just picked up a used 98 A4, having same problem i look like a kid out of high school trying to fill up gas at the pump, twisting, pushing and turning the nozzle every 20seconds. I will give the upside down trick a try today. From the search it seems the canister could be the culprit ?? I dont have any knocking sound just this hard to fill up gas.. Anyone have suggestion where to pickup the canister ?

[jimrobbington]

I just picked up a used 98 A4, having same problem i look like a kid out of high school trying to fill up gas at the pump, twisting, pushing and turning the nozzle every 20seconds. I will give the upside down trick a try today. From the search it seems the canister could be the culprit ?? I dont have any knocking sound just this hard to fill up gas.. Anyone have suggestion where to pickup the canister ?

Most people just remove the canister all together. Iirc, the thing is close to 200 bucks. There is a good diy for it in the b6 tech section.

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[Coupee36]

When you say, most people just remove the canister all together, are you implying driving the car around without the canister?
Thanks, i followed the links above and found the DIY on removing the canister.

Most people just remove the canister all together. Iirc, the thing is close to 200 bucks. There is a good diy for it in the b6 tech section.

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[plokm]

just try cleaning the filter...i tried removing my canister but my car smelt like gas from the outside

[NODO-GT]

Hi guys,
Just to make sure, to fix the knocking, i have to replace n80 valve?

[jimrobbington]

This is the video of my knocking sound. Happened after the engine was shut off, coming from gas tank area.

http://www.youtube.com/watch?feature...&v=ozsCOanAG7w

And yes, if that's the sound, the n80 fixed it for me.

JR

[NODO-GT]

close to sound i have, but it's not that intense, there are longer pauses....
Any side effects if I don't fix it?... cuz i barely can hear it.

[jimrobbington]

It might put a little strain on your lpfp. I did notice smoother throttle response after fixing this. Its really easy and cheap, why not give it a shot?

JR

[DiertyEuroSpec]

Well Ive got this issue...I have been hearing a thudding sound over small bumps/cracks in the road and when trying to fill up today fuel litterally gushed back out the filler neck and i could?hear/see pressure building up. So have we deduced a evap canister issue?? I will be looking into this shortly..

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[Brotherturtle]

Sorry to revive an old thread, but I'm confused. I don't have the thud sound, but can't put gas in my 06 A4 Quattro 2.0T. I had this problem with my 01 Jetta. So I bought a used charcoal canister. That fixed it and I could fill up like normal once. I stopped it at the first click. The next time, it's back to the same thing. I checked the N80 valve and it's ok. Am I missing something here?

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[B7S3wannabi]

Sorry to revive an old thread, but I'm confused. I don't have the thud sound, but can't put gas in my 06 A4 Quattro 2.0T. I had this problem with my 01 Jetta. So I bought a used charcoal canister. That fixed it and I could fill up like normal once. I stopped it at the first click. The next time, it's back to the same thing. I checked the N80 valve and it's ok. Am I missing something here?

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Clear the vent tube from the canister to the filler neck. Compressed air through it from canister side to filler neck with gas cap off. Should be good to go.


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[BenMTL]

I had both the hard to fill issue and knocking issue and I replaced all the following parts with new OEM

-updated hose instead of charcoal filter ($50)
-new n80 ($80)
-new fuel filter ($30)
-new EVAP box ($200)

Now I only have the knocking issue (much less but still) and have given up on resolving it.....

[Brotherturtle]

Clear the vent tube from the canister to the filler neck. Compressed air through it from canister side to filler neck with gas cap off. Should be good to go.


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I don't understand what could clog that line. But at this point I guess anything is worth a try.

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