Gas fumes in garage?

[shainiac]

Be careful running a sealed fuel tank. By not having a path for air to enter the tank as fuel is being consumed, a vacuum can be created. Pumps are pretty sensitive to pressure changes at the inlet and a slight vacuum in the tank can make a significant change in the max output of the pump. Maybe not a huge deal for NA cars, but potentially a headache for FI cars using bigger pumps and consuming more fuel. Also, no vent can make filling fuel at the gas station a pain. The sensor in the end of the station pump will kick off almost instantly if the vent isn’t working properly.

[Cobranut]

Be careful running a sealed fuel tank. By not having a path for air to enter the tank as fuel is being consumed, a vacuum can be created. Pumps are pretty sensitive to pressure changes at the inlet and a slight vacuum in the tank can make a significant change in the max output of the pump. Maybe not a huge deal for NA cars, but potentially a headache for FI cars using bigger pumps and consuming more fuel. Also, no vent can make filling fuel at the gas station a pain. The sensor in the end of the station pump will kick off almost instantly if the vent isn’t working properly.

That's true.  Also, if you parked the car hot, and it cooled down it could potentially draw enough vacuum in the tank to collapse it. 

[kinger]

All true if it were actually sealed tight.  By law there has to be built in gas cap vents.  I forget where I saw that, I think on the Stant literature in the fine print.  Dunno seems to work I keep checking of the tank is moving at all and nothing.  I should pressure test it to see when it releases and when it opens for vacuum.

 

[yusoslo]

Kinger, can you send a link to that gas cap you have?
I am thinking since this is a weekend toy and doesnt get driven during winter months this method will work while stored. Then when driving swap gas caps.

I will also run a gas tank vent filter as well so I have vacuum when needed and hopefully this filter will help. I have seen fancy $50 racing ones, but this seems like it works

https://www.wolverineforums.com/forum/9-wolverine-general-discussion/717-extra-fuel-filter-gas-tank-vent-update.html

[kinger]

This cap:
https://www.partsgeek.com/gbproducts/DC/8607-05066245.html?utm_content=DN&utm_term=1993-1995+Mazda+RX7+Fuel+Tank+Cap+Stant+93-95+Mazda+Fuel+Tank+Cap+94+1994&utm_source=google&utm_medium=ff&utm_campaign=PartsGeek+Google+Base&gclid=EAIaIQobChMI0cehsuXC3gIViLfACh3MEAHSEAQYAyABEgKUnvD_BwE&ad=47433967812

I like that fuel filter vent idea, I may add that to mine.