I found tank under vacuum pressure below 1 quarter of a tank. Is something clogged? or do I scrap the non-vented gas cap (tight seal)?

a vented cap lets air in, not out. i would think its either normal. or your vent line goin to your canister, under the hood, is plugged, or not functioning correclyt.

ok. After drilling hole in non-subaru tight sealed cap, The car runs better.I now have a gas smell at idle from engine compartment, I stuck my nose under the hood and can't find a damn thing, I did localize it close to the tbi,to no exact place of origin. I have to rule out all vacuum lines and canister( i did much replacing and clamping). Is there a common prob related to this? Invisibles are quite a peeve.....

U said vaccum pressure,.. aren't they opposite to each other????

 

When you open the cap, does air rush out or does it suck air in?

 

Mine blows air out when i open the cap

 

Gannon

Ok, not to start insulting... I'll explain slowly as I can......

 

To take a fluid from a containment needs something to replace it, unless we are riding an exact expansion into a different density for our fluids end journey (and even then, the replacement for what goes missing has to happen eventually) . Air seems to be the "freeby" most gas tanks utilize.

My tank wasn't getting it. It desires the gas cap to be vented. Of course

after all this it means tank went vacuumed(before I vented cap).

My question is ... By oem build was SPFI loyale (1993) a vented gas cap,

or is it another means to vent tank.If not so I've got a problem!! I have book that reveals many engine facts, does not talk about the gas tank (

you would think that it would be very much part of the fuel system, in detail!) Ahhh, the "haynes" books are so thorough... (you should have seen the diagram to put ECM in test mode! I had to figure it out on my own, it was nothing like it.)

AFAIK, all vehicles manufactured for the US market from a certain date that predates most, if not all, Subarus that we are likely to own are required by EPA regulations to have a non-vented gas cap. The fuel system venting is accomplished through the vent line that comes forward to the charcoal canister.

Ok, thank you. I purged something strange letting it vent, I am back to non-vented (vacuum only), running good with no gas smell. Hot days and low on fuel gave me hissing noise loosening cap, I overthought the situation.