I have had a p0440 code for some time now, Thought i cured it when i replaced a rotten fuel filler neck, but it returned shortly thereafter. Also, when i replaced the filler neck the car stopped accepting gas! Had to fill it with a gas can!

Spent most of the labor day weekend trying to sort this out, Apparently there is a valve on the filler neck. It opens and closes when you put the nozzle in to refuel. I had the two vacuum hoses backwards and that is why it would not take fuel. (it only works in one direction).

After about 60miles the cel was back on po440. So, I had replaced all the lines(yes all) and checked all the valves. I had an idea.....I disconnected the tank line from the canister and pressurized the tank! I hooked it up to my compressor, and put in about 10pds of air. Then listened for leaks. Sure enough, that same valve at the filler neck was leaking air bigtime!!

I gooped it up with rtv and so far no cel ,but I would like to replace the entire valve. Here is the problem...Its not listed in subaru parts manual! Cant find a part . A pic of the filler neck assembly does not even show this valve! Im not even sure what its called. Anyone know how to go about getting a new valve? Part number, name anything? thanks

42084FA100 or 42084AE100

 

http://www.subarupartsforyou.com/cp_partdetail.php?partid=16370

Do you mean the valve was backwards?

 

Does this diagram help?

http://opposedforces.com/parts/legacy/us_b11/type_25/intake_and_supply_system_turbocharger/fuel_piping/illustration_6/

Thanks mike. Good part number. Junkyard has 4 soobs. 2 had the valve and both were blobs of rust. Cheapest I could find was 55. The cel is back po440, so I guess the rtv didn't work and its leaking.