Gas cap fuel leak - 94 Legacy Turbo wagon

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burnt_toast
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Gas cap fuel leak - 94 Legacy Turbo wagon

Post by burnt_toast » Sun Jan 31, 2016 10:07 pm

It didn't look like any other forum section fit, so posting here:

Having gas/vapor build up in fuel filler neck. Car is at 173k mi and no rust. The filler tube itself seems intact, and I was able to fill up a full tank in normal time, no problem. Which I've read can be gas bad vent valve when it takes long time to fill up, not sure if that rules it out.

Anyway, it seems to be building pressure inside fuel system even when car is off. Thinking gas cap wasn't venting, I took it off and just let it sit like that until I could get a new one. Few hours later I see gas pouring out, coming directly from the filler.. Not spraying, but trickling out at a steady rate.

Put the gas cap back on, but its not a fix. Also after car is turned off, there is a sound from the rear like fuel pump is still working, could be related?

Would really appreciate any advice on what to do, and just really hoping I don't have to drop gas tank... fak that would suck
'94 Legacy Turbo Touring Wagon; kyb gr2's/mostly stock
'05 Toyota Corolla XRS - 1.8L 2zz-ge, 6speeds of revtastic fury

rallyak
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Re: Gas cap fuel leak - 94 Legacy Turbo wagon

Post by rallyak » Sun Jan 31, 2016 10:31 pm

Few questions:

Where is you location? What's the temperature swing from night to day?
How full do you fill your tank?
How many miles did you drive after the last fill up?
Where do you park? Is it flat or a hill or leaning left or right?
Charles

90' White/Gray Outback DD workhorse (670,xxx) miles
92' Onyx Metallic (430,xxx) Wife's DD
68' Barracuda formula S 340 4spd coupe (ongoing project)
66' Mustang 2+2 4spd wife's (ongoing project)

Pntaste4evr99
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Re: Gas cap fuel leak - 94 Legacy Turbo wagon

Post by Pntaste4evr99 » Mon Feb 01, 2016 1:54 am

My wife's NA wagon was doing the same thing kinda, except hers shot fuel/spray when she took the cap off to put fuel in. I traced it back to the purge valve and charcoal canister. Hers never threw a CEL either...

Just my two cents but check those things if u haven't already.
94 Winestone SS 5MT Rob 550 20g. (Pickle)
Original WA car with 460k miles and climbing

burnt_toast
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Re: Gas cap fuel leak - 94 Legacy Turbo wagon

Post by burnt_toast » Mon Feb 01, 2016 8:07 pm

Pntaste4evr99 wrote:My wife's NA wagon was doing the same thing kinda, except hers shot fuel/spray when she took the cap off to put fuel in. I traced it back to the purge valve and charcoal canister. Hers never threw a CEL either...

Just my two cents but check those things if u haven't already.
good idea, i will look into that.

so also, my mistake I thought the gas cap was vented. just assuming that from previous work on scooters, granted they had simple gravity fed carburetors.. The guy at autozone told me fuel tank is pressurized and the gas cap odes not vent, is this correct? either way, got a new cap with a pressure release button that I can press before filling up next time to purge any excess vapor, will see how that goes.

rallyak,
I just bought this Legacy Thursday of last week and have only had it for 4days, so limited data as I didn't plan to drive until doing a full once over, driven maybe 10mi after fillup. Has been sitting in driveway, on about 30deg inline.

in other news I just figured it would be okay with new gas cap and drove out to meet a friend, 10more mi. drove well, but CEL on. then parked back home, CEL went away, the noticed smoke from hood and looks like she's spewing coolant somewhere and it was burning of on header.. gah. sprayed with a water hose immediatly to cool it off. have not looked into this new issue yet.. this journey continues, kinda off to a rough start
'94 Legacy Turbo Touring Wagon; kyb gr2's/mostly stock
'05 Toyota Corolla XRS - 1.8L 2zz-ge, 6speeds of revtastic fury

Legacy777
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Re: Gas cap fuel leak - 94 Legacy Turbo wagon

Post by Legacy777 » Tue Feb 02, 2016 7:55 pm

The gas cap is designed to hold pressure and I believe is set to relieve pressure if it gets too high. I believe there is a page in the factory service manual that describes the operation of the gas cap. You can review the stuff you need to know forum and the sticky threads to download the factory manual.
Josh

surrealmirage.com/subaru
1990 Legacy (AWD, 6MT, & EJ22T Swap)
1997 Impreza OBS

If you need to get a hold of me please email me rather then pm

burnt_toast
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Re: Gas cap fuel leak - 94 Legacy Turbo wagon

Post by burnt_toast » Tue Feb 09, 2016 12:11 am

Legacy777 wrote:The gas cap is designed to hold pressure and I believe is set to relieve pressure if it gets too high. I believe there is a page in the factory service manual that describes the operation of the gas cap. You can review the stuff you need to know forum and the sticky threads to download the factory manual.
Thanks for the info, that is certainly on my to-do.

Small update on the second issue, traced coolant leak to upper rad hose, looks like previous owner clamped down on the hose clamps too tight and it had a slight tear. Just replaced, and looking good so far.
'94 Legacy Turbo Touring Wagon; kyb gr2's/mostly stock
'05 Toyota Corolla XRS - 1.8L 2zz-ge, 6speeds of revtastic fury

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