DIY: Carbon Canister Fix / Pumping Gas Problem

**plokm** · 11-01-2011 04:11 PM

If you are having trouble pumping gas then you might want to try this out.

Possible Causes: clog carbon canister filter or leak detection pump (LDP)

Tools needed:
10mm and 13mm socket
Flathead
Pliers

Step 1: remove the three 10mm nuts and drop the cover. After you remove the cover it should look like this.

Step 2: Unplug the hoses by pushing the round plastic ring toward the carbon box and pulling the hose out. It’s a PITA because the hose is really in there and you also have to be careful on not breaking the hose.

For the skinny hose I used a flat-head for leverage (shown below). That hose leads to the n80 valve and the larger one goes to the gas tank. You should unscrew the gas cap the try blowing into the large tube to see if air flow through it. If air doesn’t flow through that might be your problem.

Step 3: use pliers to remove the clamps on the hoses

Step 4: remove three 13mm bolts and drop the carbon canister

Step 5: remove the carbon canister filter

Step 6: Clean the filter

option 1: Blow air into the filter it should go through fairly easily. If you feel like there resistance then it need to be clean. I cleaned my filter by filling it with water and blowing air through it. I also sprayed carburetor cleaner in it and let it soak in the filter for few mins.

OR

option 2: You can cut it open to clean it but you will have to seal it tight. If not an evap cel will come on.

Step 7: Test to see if the LDP is clog by blowing into the single tube near the driver side. Air should be able to go through it fairly easily too.

Step 8: Put everything back together and make sure all of the hoses are on tight. If not you will get an evap leak CEL.

**doublezero30** · 11-01-2011 06:15 PM

nice little DIY. not sure ide cut mine open, but to each his own. good writeup regardless

**mr_esmit** · 11-02-2011 08:50 AM

Isn't the carbon canister filter sold seperately??

**A4B7GA** · 11-02-2011 12:55 PM

Thanks for this. I am taking my 5.5 back in again for the 3rd time for the filling issue. I am using their recomended stations and nothing seems to work. I finally got AOA involved as this time I am out of warranty.

***kristokes*** · 11-02-2011 02:09 PM

Thank you for the write-up

I'll move this into the B7 A4 tech soon...

**plokm** · 11-02-2011 03:15 PM

Originally Posted by mr_esmit

Isn't the carbon canister filter sold seperately??

nope

**Hazziar** · 04-13-2012 10:07 PM

Awesome solution, thanks for figuring out a practical fix thats basically free to do! I did this DIY on my charcoal canister after I verified it was clogged [couldn't blow air through it]. It completely solved my fill up problems and the knocking noise from the tank that many people experience with this problem. The only things I did different was I cut right below the bonded top cover for a clean separation and removed the thin mesh screen from the cover as that is what was clogged.

**Giantsfan10** · 04-14-2012 12:54 PM

what is the pn for a whole new unit? it must be like a 350$ part right?

**luisrsg** · 04-16-2012 02:45 PM

How did you guys seal everything back together? Do you happen to have any pictures of how it looks after you sealed it? Thanks

**plokm** · 04-16-2012 02:50 PM

i didnt cut mines open...just rinsed it with water

**luisrsg** · 04-16-2012 05:54 PM

Originally Posted by plokm

i didnt cut mines open...just rinsed it with water

Did this solve your problem? Did you do this with the filter only or the whole canister itself?

**plokm** · 04-16-2012 08:33 PM

Originally Posted by luisrsg

Did this solve your problem? Did you do this with the filter only or the whole canister itself?

yes it did and just clean the filter...do not try to clean the canister. Water will damage the canister.

**luisrsg** · 04-17-2012 02:06 AM

Originally Posted by plokm

yes it did and just clean the filter...do not try to clean the canister. Water will damage the canister.

ok thanks man! i'll try it this weekend

**Giantsfan10** · 05-14-2012 05:56 AM

i took a look at mine last night. i have a 2007 and it doesn't have the little canister on the side. it just has a curved hose that goes right to body mounted hose. what the do i do now? does the LDP filter do anything regarding filling up?

**plokm** · 05-14-2012 02:24 PM

Originally Posted by Giantsfan10

i took a look at mine last night. i have a 2007 and it doesn't have the little canister on the side. it just has a curved hose that goes right to body mounted hose. what the do i do now? does the LDP filter do anything regarding filling up?

you should have it

**Sandman1** · 05-14-2012 05:34 PM

I to need help had a code p0445 which I fix , new cap which was warn out and purge solenoid valve now I am getting code p0442 any ideas

**papadelogan** · 05-14-2012 07:02 PM

I wasn't getting any codes but was having the fuel cutoff issue when filling. I scored the entire canister assembly with only 15k miles for ~$60 off ebay. You might try looking for an ad of a car being parted out and contact them about the canister.

**ChriS4B7** · 05-26-2012 10:41 AM

This is why I love the message boards, because this is a problem that so many of us have and when someone finally finds a good cheap fix it spreads like wildfire. You've saved so many people so much money. Thanks plokm!

**k20actr** · 05-26-2012 03:31 PM

it work's

**denali206** · 10-01-2013 08:23 AM

From what I understand, the charcoal filter is the cause of the issue. I wonder if it's possible to bypass the filter and connect a long hose hose and be done with it? I tried purchasing the vapor canister but it didn't come with a filter and there's no way to purchase a filter separately. I'm reluctant to cut the original charcoal filter open because I fear I won't get it resealed and or I'll need to clean it regularly. Can anyone direct me the right way here?

**plokm** · 10-01-2013 09:08 AM

You can bypass it but some people eventually have problem with the LDP..I didn't cut mines up...I just spray alot of carbon cleaner inside of it and I was good to go

**denali206** · 10-01-2013 04:49 PM

That's what I'll try. Thanks for the reply!

**denali206** · 10-05-2013 07:00 AM

Cleaning the small filter on the side didn't fix my issue so I'm completely replacing the vapor canister and following the Audi recommendation to bypass the small filter on the side with a hose, PN 8E0-201-946-H. If this doesn't do the trick it's on to the LDP.

**jimrobbington** · 10-05-2013 08:54 AM

I removed the entire thing all together. Why do you want to replace it? There is no cel.from removing it.

**denali206** · 10-07-2013 07:48 AM

Hmm, I've been reading a lot and was under the impression it would through codes and I believe someone mentioned it causes issues with the LDP. In any case, I replaced the canister, purchased a 5/8" heater hose and bypassed the charcoal filter on the side. So far so good, the engine seems more responsive, smoother and I can finally fill up quickly rather than waiting 20 minutes.

My next project... motor mounts. The fun continues.

**jimrobbington** · 10-07-2013 08:49 AM

Yeah, I read there would be codes too, but I have none. Lol. Maybe things changed in the later models, but as for my 05.5, everything is good. It's so nice to be able to fill the tank with one click.

**tallp1g** · 10-11-2013 06:19 PM

I am finally fed up. I have had filling issues for years. Recently I ran out of gas on the highway even though my gauge showed I had gas. Often on long trips my needle doesn't seem to even move until I stop.

In any case, I just followed the steps above. My one question I had, In Step 2, I blew into the large hose that leads to the tank. Air went in easily but it also blew back out at me. I had removed the gas cap. What should I expect with this test?

EDITING: 11/5/2013
After completing the above steps I have successfully filled up twice (11 gallons each time; two different stations) with no issues. The knocking sound I would experience after shutting the car off is also gone.

**Whats4dinner** · 10-11-2013 11:58 PM

Interesting and thank you for the write up. My problem is that I will go to the pump and my gas needle will never indicate that my tank is full, it will get close to filling up (according to needle reading), but maybe has a half-quarter tank left to fill...even though the gas machine itself has clicked.

**jaycurn** · 11-20-2014 10:30 AM

Going to give this a try and will probably just remove the charcoal canister and rteplace with either this part: 8E0-201-946-H
as mentioned above or just a piece of bulk hose since the dealer wants $70 for this piece of rubber hose!

Does anyone have specs as far as the diameter and length of the hose required??

**fly300kts** · 11-20-2014 10:42 AM

Originally Posted by Whats4dinner

Interesting and thank you for the write up. My problem is that I will go to the pump and my gas needle will never indicate that my tank is full, it will get close to filling up (according to needle reading), but maybe has a half-quarter tank left to fill...even though the gas machine itself has clicked.

Your problem is most probability coming from the fuel sender

http://www.audizine.com/forum/showth...ghlight=sender

Phil

**6speedman** · 11-20-2014 11:10 AM

Awesome DIY!! I'm going to be doing this this afternoon. I just fueled up this morning in 10* weather. What a pain to be trying to coax some gas in.;(

Sent from my iPhone using Tapatalk

**mcbuck** · 11-20-2014 11:39 AM

Did this last winter. Works as advertised! Now I just lock it on wide open and let it go - FTMFW!

**jaycurn** · 11-20-2014 11:43 AM

Originally Posted by mcbuck

Did this last winter. Works as advertised! Now I just lock it on wide open and let it go - FTMFW!

Did you clean the charcoal filter, remove it or just take the whole charcoal canister and evap tank out as done in this DIY?
http://www.audizine.com/forum/showth...Detection-pump

I think rather than replace the charcoal filter alone with a hose, I might just take the whole assembly out!

**jimrobbington** · 11-20-2014 12:09 PM

Originally Posted by jaycurn

Did you clean the charcoal filter, remove it or just take the whole charcoal canister and evap tank out as done in this DIY?
http://www.audizine.com/forum/showth...Detection-pump

I think rather than replace the charcoal filter alone with a hose, I might just take the whole assembly out!

Do it! My gas pump has not clicked off prematurely since. And no cels from removing it all either.

Also, the hose is cheap, and i followed the instructions, but one hose wasnt the correct size. My recommendation is removing it all, and if you have a second vehicle, take the old parts with you to home depot and match the tubing that way. Just to avoid having to go to the store twice like i did.

**jaycurn** · 11-20-2014 12:26 PM

Perfect... thanks sir! Can anyone confirm hose sizes etc to avoid a mid job parts store mission?

**SmoothCriminal** · 11-20-2014 12:31 PM

Incredibly useful, I have had P0455 since I got my car (which has only been a few weeks) but I'll definitely give this a try tonight. Thanks!

Update: So I'm out here under the car and just had a thought. If you leave the gas cap on should you be able to blow into the large hose? Just trying to determine if that would tell you if your gas cap was bad.

**Jey4** · 01-31-2015 06:40 PM

Thanks for this DIY. I followed it a few weeks back and worked like a charm. I didnt cut open the filter just ran brake cleaner through it a few times and I've been able to fill up the tank twice without any hicups.