gas cap pressure/vacuum not sure...

82Stang · #1 06-30-2006, 09:11 PM

Hi,

I replaced all 3 fuel lines and they were petrified. 3/8 main, 5/16 return and 1/4 vent. I went to get gas 8 miles away and when I pulled the gas cap off it was sounding like it had a pretty good pressure exchange, whether in or out, i'm not sure. Might be vacuum. I feel like it isn't supposed to be like that. Any ideas on what to check and make sure it is operating right? Maybe bad gas cap? Or maybe I'm wrong and it's fine. Just made me think something might not be right. Thanks all.

MT-2500 · #2 07-01-2006, 06:33 PM

Quote:

Originally Posted by 82Stang

Hi,

I replaced all 3 fuel lines and they were petrified. 3/8 main, 5/16 return and 1/4 vent. I went to get gas 8 miles away and when I pulled the gas cap off it was sounding like it had a pretty good pressure exchange, whether in or out, i'm not sure. Might be vacuum. I feel like it isn't supposed to be like that. Any ideas on what to check and make sure it is operating right? Maybe bad gas cap? Or maybe I'm wrong and it's fine. Just made me think something might not be right. Thanks all.

Might be bad or good.
What year? What engine? What is your tank vacume reading?
Most later model tanks are supposed to run under vacume.
Any check engine lights?
MT

82Stang · #3 07-01-2006, 09:26 PM

Hi,

I don't know what vacuum, but I am checking the carbon canister to see if it is blocked. No other reason for it to be so pressurized. All the lines are new so it has to be something on either end. Thanks for the reply.

82Stang · #4 07-01-2006, 09:27 PM

Oh, 93 S10 Blazer with 4.3L auto 4x4...

1stGenFan · #5 07-02-2006, 10:21 AM

Hmmm. I don't know either. I have an 89 longbed with a 4.3 and when I unscrew my cap there doesn't seem to be any pressure. Cap is an aftermarket.
I'm not sure if no pressure is right either.

82Stang · #6 07-06-2006, 11:25 PM

Aha, fixed the problem....

Thanks to the replies. I found that it was nothing at all really, just vacuum due to the fact that there wasn't much gas in the tank and the temps here were scorching. As I added more gas, it subsided and went back to normal. Just thought I had a problem here when, in reality, I had none. Funny how it works like that. I think I have a problem and nothing there. I think everythings ok and BAM, problem central!

Appreciate the help!

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