gas cap pressure ??
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From: Mountain Home AR
gas cap pressure ??
On my 86---- should there be pressure in the tank when you take the cap off or not??? If not, does that mean a line is blocked going to the canister?? And what problems can this cause???
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Pretty much normal. The canister and solinoid in the front driver corner mounted to the bumper control this. If it's not bleeding back, it will cause pressure. Probably not worth worrying about.
Last edited by zr1fred; Jul 14, 2006 at 01:12 AM.
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Its summer, its hot out, your gasoline is warm, warm gasoline has gas pressure, gas pressure builds up in a closed system, your gasoline sytem in your Vette is a closed system, when you open the gas cap, gasoline vapor exits with a whoosh. Do as Bugs Bunny says, "unlax".
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From: Mountain Home AR
Originally Posted by jfb
Its summer, its hot out, your gasoline is warm, warm gasoline has gas pressure, gas pressure builds up in a closed system, your gasoline sytem in your Vette is a closed system, when you open the gas cap, gasoline vapor exits with a whoosh. Do as Bugs Bunny says, "unlax".
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If the line WAS blocked and cannister failing,the pressure inside the tank would rise and make alot of noise and pressure on removal of the gas cap.
Some whooshing is normal,should be a low sound,brief whoosh and thats it.If its a long whoooooooooooooooosh and loud noise,the vapors arent being cycled to the cannister-through-engine and you would also sometimes have a smell of gas vapors around your gas cap.
Thats a sign of a blocked tank...the tank itself would also get very hot.
Ya have to take the spare out to put your hand down there after a drive and see the difference.
Its true the summer heat causes more pressure in the tank...happens on all my cars.
If theres no bad or extreme pressures,and no strong gas odor,your car should be good as the vapor system goes.
I had a seriosu problem with my vapor system on my former 86...the metal line was rusted clogged,cannister was failing,and the rubber hoses around the tank for the vapor system was cracked.
After I replaced all that,I had hardly any vapor whooshing or hissing noises on hot days.The tank stayed cooled and didnt feel so hot to the touch anymore.When I had the problem ,the gas smell was very strong,the cap would have so much pressure the noise was loud.The cap almost flew out of my hand on removal and the tank felt too hot to touch.
Some whooshing is normal,should be a low sound,brief whoosh and thats it.If its a long whoooooooooooooooosh and loud noise,the vapors arent being cycled to the cannister-through-engine and you would also sometimes have a smell of gas vapors around your gas cap.
Thats a sign of a blocked tank...the tank itself would also get very hot.
Ya have to take the spare out to put your hand down there after a drive and see the difference.
Its true the summer heat causes more pressure in the tank...happens on all my cars.
If theres no bad or extreme pressures,and no strong gas odor,your car should be good as the vapor system goes.
I had a seriosu problem with my vapor system on my former 86...the metal line was rusted clogged,cannister was failing,and the rubber hoses around the tank for the vapor system was cracked.
After I replaced all that,I had hardly any vapor whooshing or hissing noises on hot days.The tank stayed cooled and didnt feel so hot to the touch anymore.When I had the problem ,the gas smell was very strong,the cap would have so much pressure the noise was loud.The cap almost flew out of my hand on removal and the tank felt too hot to touch.
