Gas cap: Air rushing out upon removal when fueling. Normal?

Can't help ya here. Don't know about the 355 set up. I'm sure others will chime in.

 

I'll take you up on that. We can measure the relay heat as well. Sunday's weather is looking pretty good so far...

 

I also had too much pressure in my 355's tank.
My car is a 1995 Spider hence it still had the older ventilation valve (part #159478) attached.
Later Ferrari replaced this part with a newer version (part #170442).

I replaced my 2-way ventilation vent with this newer 170442 valve and all is well now.

The valve keeps the fuel tank under a slight pressure if it works correctly.

My old valve was not able to keep up the 0.03 bar limit (mentioned in the workshop manual) when relieving pressure towards the carbon canister.

@ready321now
The red valve shown in the picture is the older version (part #159478).
It is quite cheap so I recommend replacing it to the newer version.

 

Same on mine 355. I solved it easily by not fully tightening the gas cap. It works fine, no under or over pressure in the tank. No fuel smell either.

 

My 355 does this also, a large volume of air escaping with pressure after a hot day drive and low fuel.
So question, I was looking at Ricambi site, table 10 - fuel tank.
Can you please identify item numbers of the listed problem areas, or should I be looking at a different chart ?
Is there an easy/cheap fix or ?

Just looked at table 11 ...... Thinking this table shows the suspect part(s) ?

 

Ricambi parts table lists a #170442, 1 ea as NOT for a USA car.......
Then below a #174594, 2 ea FOR a USA car ... Also qty as 2 ea ?
Table 11 and item # 26 for both part numbers

 

Refering ready321now's picture he has a pre 1998 car.
For this car 170442 is valid and he needs one valve (no matter if US or non-US spec).

 

I checked Eurospares to see what they list. Part # 170422 is for 2.7 cars and 174594 is for 5.2 cars. I believe them to be correct.

 

Reanimating this thread...
ready321, did you solve the problem?
The picture that you posted definitively shows the 170442 valve and if you have a pre 1998 car it is the correct valve even for US-spec.

 

My 1990 348 lets out a little air when the gas caps removed but not a great amount so I'm not too concerned about it.

However:

On this one, I've noticed that too!

Does the ali engine cover double up as a BBQ grill for when you get to your destination? - I swear you could cook steaks and other meats on it quite easily!

(Just need a tray to stop the fats dripping on the engine!)

 

Many seems to have this over pressure phenomena and I hardly believe that everyone has the same failure, so I think this is normal. My 355 does the same too.