There's a serious suction whoosh whenever I open the gas cap of my 91 SE. Could I be experiencing vapor lock or is this common for Max's? I'm not experiencing any idleing problems or major lack of power ( other than the fact it's a VG ) although my fuel milage isn't the greatest.

 

That's normal, especially in hot weather.

 

i experience this whenever i run the car on e for a while.... dunno if that would have anything to do with it...

 

not sure about this, but i think that if you don't have that "whooosh" you havea problem b'/c the fuel system isn't pressurizing? i think i read that somewhere, not sure though

 

I believe you'll hear that whoosh when your tank is low.

If you check your tank when there lots of gas in it, there either wont be that sound or it will be less noticable.

I always thought it had to do with the pressure built up in the gas tank.

 

Pretty sure that is a good thing. It means your gas cap is not leaking vapors

 

Max's have a pressurized fuel system, that whoosh is a good thing... Mine hasn't done it for a while, and now that I've figured out the trick to locking my gas cap every time, it pressurizes, and I went from 14 gallons getting me 300 miles to 14.5 gallons getting me 350-380 miles.

 

That woosh is the fuel vapors escaping from the tank. Yes they will probably be worse on a hot day and if you were throwing your car around corners. Its almost the same as shaking a bottle of pop the bottle builds pressure and once you open it it releases it. Its quite normal and not to be worried about unless you are having a smoke while taking it off

 

yeah its a normal thing my 90 se does the same exact thing

 

Isn't it the sound of air rushing in? The pump is pumping fuel to the engine, therefore the fuel tank experiences a vaccuum as the headspace grows larger and the pump draws fuel away

 

nope, its air rushing out. There is a spring loaded valve in the gas cap. It allows air to enter the cap, but not exit. I'm not sure how to test the cap for proper function. But if its sucking in air when opening it, then it may be bad.

 

glad some1 posted about this cause i find it strange that my tank only "whooshes" about half the time, and my tank is always near emtpy when i fill it (less than a quarter tank) very strange, i was wondering that maybe the gas i use has something to do w/ it (as i use different brands, im not picky) hmmmmmmm

 

I lost my cap (drove away with it on the roof, doh! smoked that one away!) replaced it with a Stant replacement. I get about 350 miles on a full tank. So what's the trick to locking it, just turn till it clicks a few times right?

 

its like opening a bottle of soda after you shake it up, the air inside the tank

 

but gas isnt carbonated....

 

Ya, that's the trick with mine. It used to lock with one click, now it takes 2... But that's how I got it to finally lock, and since I have, I've gone from 300 miles/tank to 360-380

 

I remmember reading that when closing the gas cap that you should do 3 clicks (normally). Thats what I've always done. I gonna try four and see if there is any diff.

 

Man yall are carefull. When I put my cap on I just turn real hard and let it click several times (after all it is a clutch type deal to prevent over tightening)

 

<chuckle> I'm not careful, I'm lazy Now I check to make sure it's locked before I close the cover. I had 417 miles on 15.4 gallons of gas today 27.08MPG, ya baby!