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Guest Message by DevFuse

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Troubleshooting Assistance Request: Fueling Issue + Trouble Code

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5 replies to this topic

#1 DirtyMech


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Posted 10 August 2013 - 05:26 PM

Hey All,


I've got a 1999 Subaru Outback Wagon LTD 2.5L, MT, Dark Green, 190,000 miles.   

I live in California but the car is probably from out-of-state - had to install a second cat to pass smog.

Since I've owned it, it has had a hard time taking fuel.  This means that when I try to fill up the gas tank,

the nozzle keeps clicking off as if the tank is full.  I've noticed that if I pull up the rubber cover around the 

gas nozzle while fueling, so that any excess air pressure can escape from the tank, the overfill safety is

less likely to be tripped and click off the nozzle.  I assume this is some kind of EVAP or fuel vapor issue.


I searched the forum, and the problem is more or less identical to this gentleman who owns a 2005 Legacy:


Now comes the issue.  I'm trying to smog (and sell) my vechile for top dollar and need this issue resolved.
However, my CEL is on and a trouble code came up which I believe is strongly related to this problem:

P1443  - EVAP Control System Vent Control Function Problem - according to http://www.troublecodes.net/Subaru/

I am looking over my Haynes manual of my book, as well as the previous forum thread, for things to troubleshoot

and will update this thread as I conduct troubleshooting tests and learn further information.  However, if anyone is

familiar with this particular problem and its symptoms, I would appreciate some clues. =)


Edited by DirtyMech, 10 August 2013 - 05:29 PM.

#2 DirtyMech


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Posted 10 August 2013 - 08:27 PM

(Note: I've been searching the forums more and found this related post, although not seeming much more helpful than the other)


So I've removed the rear right tire and the cover for the fuel filler neck.  Found a lot of mud / dirt around the top

of the neck and heavy rusting.  I suspect the heavily rusted (purge?) valve may be faulty in this case. and I may

even need to replace the filler neck because the rust has corroded the parts for connecting the valve. 

Can anyone answer the following?


1)  What is the name / part # for this valve?

2)  How can I test its operation?

3)  Do I need to remove the neck or tank to replace this valve? I see there is a nut on the far side that is difficult to reach.

4)  Will I likely need to replace the filler neck as well due to the heavy rusting?

Thanks for all input!

Pic 1: This is the top of the filler neck and the heavily-corroded valve can be seen on it's side.




Pic 2: Zoom Back View


Pic 3: All the Dirt from around the Valve.  Done by bugs?



I also found this cool YouTube video on the same problem.  But it's a Toyota.  I wonder if Subaru has a comparable part causing this. 
I may remove the charcoal cannister/brick box and see if I can find any clogged parts if I get desperate:

Edited by DirtyMech, 10 August 2013 - 08:48 PM.

#3 DirtyMech


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Posted 10 August 2013 - 09:00 PM

So here's what I've done since last post:

- Checked the USRM for related entries: none found.

- Realized my Haynes manual covers 90-98 but not my 1999 model, which has the EVAP under the rear of the car.

- Searched Oreilly, Autozone, and Active Auto Parts (online) to try and ID this part; unsuccessful.

No filler neck for sale seems to include this valve either, although there is a space for it on the neck.

- Still Searching online for a Diagram that might name what is this part / rusty valve on my filler neck.


Starting to get desperate here.  Any info in the right direction is appreciated.

#4 Fairtax4me



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Posted 10 August 2013 - 11:10 PM

Pretty sure that vent valve is built into the filler neck.

The dirt is from your tires flinging water, dust, sand, mud, etc all around the wheel well while driving.

#5 DirtyMech


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Posted 10 August 2013 - 11:49 PM

Thanks Fairtax!
Okay, I will call a parts dealer on Monday and check the product to see if it is built into the neck.
I could try to find a replacement at Pick N Pull too... 

In the meantime, is there any way to test to see if the valve is functioning properly? 

Also curious to know if I can change the neck without lowering the tank. xD

I found an old thread on our mystery valve. It looks to be a fuel filler neck valve or fuel cut-off valve:


Here is also some conversation advising AGAINST replacing the plast filler neck cover due to its role in causing rust to form:


Edited by DirtyMech, 11 August 2013 - 02:13 AM.

#6 DirtyMech


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Posted 11 August 2013 - 09:33 PM

Okay so I think I may have resolved this problem.  I'm not sure exactly what I did that may have resolved it, but here's the data:

- I found a hose that was slightly raised above, and therefore slightly pinched, by it's plastic half-ring retainer.  According to

the Endwrench article on "Vehicle Won't Take Fuel" (found posted by a member in the thread link in the top post), "Hose

obstructions that appear as small as spider webs can cause refueling problems."  So this may have been what resolved the issue.

- I banged the crap out of my rusty overfill protection valve at the top of the gas filler neck.  Hoped this may have loosened anything

that was stuck inside. 


-  I removed the charcoal cannister (or brick, to be precise) and the vapor shutoff valve and tested its function.  I found that it worked

in test mode, and that it sealed fully, and that the Ohm reading was between 28 and 31.  According to this video which recreates what

I did, the proper Ohm reading is 30 to 50.  I don't think the vapor valve had anything to do with my problem based on thse observations:

- I blew into any hose I could detach and tried to see if there were any obstructions.  I may have knocked some crud looes in the process.


- After doing all this I put everything back together and drove down to the gas station.  Was able to refuel from a 1/4 tank to a 3/4 tank

without the damn thing clicking off.  This is good evidence but not conclusive proof that the problem has been resolved, as I have not

been able to do this for a long time, if ever.  I'll fill the rest of the tank later this evening to see if the fix has remained.

I noticed that I have not heard the "sucking" sound of a vaccum seal being broken when refuling in the past, but when I removed the

gas cap after driving around today, I did hear the slightest sound of a vacuum seal being broken.

BUT - After all this work, the computer is now throwing me a P0325 code (knock sensor), so now I'm going to have to fix that one. Go figure. 

Edited by DirtyMech, 11 August 2013 - 09:34 PM.

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