BluthndrZ28

iTrader: (1)

Does anyone else have the same problem I do when the gas cap is opened & a wonderful hissing sound escapes??
Is this a camaro thing, as a friend of mine who owned an '88 iroc had the same problem. I bought a new cap but it has not worked, it's not a huge deal, but if there is a way to get rid of it, then I'd like to ... any suggestions??

easySPEEDcamaro

yep same thing happens to me.

George

There was a lot of vapour released on this board about that subject quite some time ago.

It should come up if you search under hissing gas caps or something like that.

Edit: not that the world turns on it but as far I know vapour lock is actually a fuel deliver problem - like it starts boiling in the lines or in an electric fuel pump that's running too hot - so you get vapour in the system and therefore a lock.

RegaPlanet

yea actual vapour lock has to do with air in the fuel lines due to heat from a fuel pump possibly or having your fuel lines placed to close to your exhaust. I used to have this problem with my R/C

Only car I've ever witnessed the hissing gas cap with was my gf's Protege.

Slade1

Vapour lock was more a problem on carb engines than anything else where the fuel would boil in or near the carb due to low fuel pressures preventing fuel delivery. This usually caused a non start condition.

The sound you are describing from your gas cap is the sound of a HEALTHY PRESSURIZED FUEL SYSTEM. EFI engines need the higher pressure to keep the injectors firing properly, a well pressurized system takes stress off the fuel pump to keep the system pressurized. If your gas cap isn't releasing pressure when you open it after a good long/hot run on your efi car you better find out why else you'll be looking at a fuel pump replacment in the coming years...

Stroked-Z

Fuel expands & contracts with temperature doesnt it?

I've always been told this, and that's the hissing sound

Slade1

Yep, which is why if you open your tank while the car is cold you won't hear it as per say when running it hard and hot.

What it comes down to is you do not want to get rid of this condition on an EFI car. It's a perfectly normal sound and if your car doesn't make this sound after running hot, you could have a leak in your system.

BluthndrZ28

iTrader: (1)

Just wanted to thank you all for the feedback & it sounds to me like my system is up to par & there are no problems to be concerned with.
Thanx!!!

Steve89GTA

Slade is right. Hissing from anything other than the gas cap (aka a snake) is something to be worried about. Otherwise, sounds perfectly normal to me.
I love the hiss from the gas cap. People look at me strange when I unscrew it at gas stations, lol - almost like back to the future when he refuels the deloreon..
I think it sounds cool...