86 s3 fuel tank whoosh
 

This one is driving me nuts.

Fuel return to both tanks is fine, but even short runs lead to the dreaded whoosh when I crack the fuel lid. Also, when fueling up, the gauge will go to, say, between half and 3/4. Ten minutes later at home, after switching off, I get half showing.

Quite simply: HEEEEEEEEEEEEEEEEEEEEEELLLLLLLLLLLLLLLLLLLLPPPPPPP PPPPPPPPPPPPPPPPPPPPPPP

RE: 86 s3 fuel tank whoosh
 

I eliminated the vapor buildup which causes the whoosshhh and stretches the tanks to the point of leaking, by removing the one-way plastic check valve located under the front, right, (passenger side) fender. It is a well known problem.

This valve looks like a little canister, it can be seen once the tire and wheel are removed, it is connected between two rubber hoses, one being larger diameter than the other, the hoses are attached to the inner wheel panel.

The first optionis to replace the check valve with a plastic hose open connector which has steps for different diameter hoses on each side. Do not leave the hoses open to atmosphere. You can get the connector at any auto parts store.

the Second option is to remove the check valve andpush a 1/8" drill bit in one side and pull it out the other. This will break the membrane that is causing the vapor buildup.


Jose