'95 355: Gas flowing out of tank

Yesterday I was going to participate in a track day. I filled up but not overfilled, just prior to getting to the track. When I parked at the track I noticed a small puddle of gas in front of the left rear Tire. I opened the gas cap and gas flowed out. Eventually it stopped to a trickle after probably a litre or 2 came out. The fuel pump was not running. Fortunately there were a couple people more technically inclined than I there. They removed the valve seen in the photo below. Hey sucking sound ensued and the gas then receded back into the tank. The valve was then placed back in place. (backwards as I later found out but not sure this is relevant, since corrected but have not driven since). I then went out and did several 10 minutes sessions, checking to ensure all is well after each and the problem has not reoccurred.

Any ideas as to what caused this? And is this likely a one time event or something I should be significantly concerned about?

Thx
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My '95 did this once at the gas station but it wasn't quite that much spillage. I thought I over filled it trying to gear up for a long journey.

Mine has not had any issues since then. Although both my 328 and my 355 have pressure releasing when I took off the cap - especially after driving a while.

Best.

Robb

 

I don't have any help to offer on the fuel. I would recommend updating the power steering fluid reservoir. The old style reservoir has a nasty habit of blowing the lid off at high RPM.

 

Fuel Rollover valve stuck?

 

It looks to me that the rollover valve is a mechanical type valve and won't stick on unless turned upside down first.

 

Change it asap dont mess with gas issues

 

Can you elaborate on what and where the rollover valve is?

 

Located under the lip of the rear side panel just behind the gas filler door area...

Mine had gone bad, and was replaced, THEN bypassed by the shop I took it to. Not sure I can explain why.

 

I am not sure how to post a pic but its in the workshop manual, it explains how it functions and if you do not have one look on ricambi s website and it will show a pic of it plus then you will have the part number.

 

Section c page 43 and 44 describe the roll over protectin valve and the two way breather valve. Before you order a roll over protection valve I would bench test it. My guess would be its one of the other components, either the charcoal canister unless this cannot be plugged (I am not sure) or the two way valve which could be stuck. The two way valve is designed to equalize pressure in the system always keeping a slight vacuume. If its not working properly your vacuume might become excessive. Because its a sealed system I can see to much vacuume causing your problem as air escapes to rapidly pushing gas up the neck. Someone else might be able to explain the charcoal canister.