I have an 89 L98 and thought that I read on one of the forums in regards to this question before. When you remove the gas cap should the tank be pressurized or not. Whenever I take the cap off to fill her up she always sounds like a leaky tire at first, till all the pressure is realeased. Is this normal or is something not right????
Thanks Guys, look forward to the replies!

Fred

 

I believe this is normal, mine does the exact same thing.

 

That is right on if it didn't you would have a problem.

All fuel system's by law have to sealed today.


today. :thumbs:

 

:bs

That's what the charcoal canister is for, to vent the fumes from the tank. Here's a pretty extensive thread on how to fix the problem.
http://forums.corvetteforum.com/zerothread?id=416149

 

Your to much, all that did was say that the fuel sys. has to be between 7&10 psi.

LIKE I SAID ALL FUEL SYSTEM"S HAVE TO BE CLOSED!!! IT"S THE LAW!!!!!!!!!!!! [IMG]If you're ever working on your vette, and leave the fuel lines disconnected, say at the fuel rail, then you must open the gas cap, then push in the schrader valve to vent the fuel pressure. This is obvious.
But, DO NOT put the gas cap back on until the fuel lines are reconnected.

I was working on my vette last night till the wee hours of the morning, and put the locking gas cap back on (because I'm paranoid about one of my roommates) and went to sleep. A mere two hours later, I went back in the garage, and it was filled with gas fumes, and there was about a gallon of premium on the ground, and it was still weeping out. It would probably be much worse had I left it for 6 more hours.

The garage isn't insulated, so as it heats up, the fuel heats up, and forces gas out of the system. Gasoline can also dissolve RTV, especially if it's still setting up.

The sealed gas cap is purely for emmissions, nothing else. Because of those damn dirty hippies, I could have burned my house to the ground! I bet smoldering fiberglass, rubber, paint and roofing tar is much worse for the environment than gas fumes!


STL94LT1
Senior Member


1897 posts [100%]
Ofallon Missouri

Re: Public Service Announcement: Fuel fire hazard to the home mechanic (CentralCoaster) 1:20 AM 8/11/2003

[/IMG]


[Modified by offershore, 5:13 AM 8/11/2003]

 

The vapor cannister will vent the excess fuel vapor pressure into the intake when the engine is running, above a certain temperature or speed.

Until then, it is an enclosed system. If you leave your vette parked in the sun, pressurized at the gas cap is normal.

But, IT SHOULD NOT be under pressure immediately after you park it after driving. Most likely, you have clogged fuel vapor lines, or malfunctioning vacuum valves or purge solenoid.

 

As Always, thanks for the info I will check into those particular items. Obviously still pressure when filing her up and I had to drive there so something must be plugged or malfunctioning............

 

Mine does the same. So does my Durango and Jimmy.

 

(sigh) The last three C4 Corvettes I had (have) have a warning on the gas cap to release the cap slowly to relieve the pressure. I have a locking cap and when I turn the key you can hear the hiss. The tanks are NON-VENTED and pressure in the tank after a few miles is NORMAL.

 

I disagree. After reaching 40(?) mph the vapor cannister purge solenoid will allow vacuum to the vacuum valves, which "purges" the excess pressure into the intake manifold via the PCV line.

Mine was clogged initially, i blew out the vent lines with compressed air to fix it. The gas cap no longer rushes air out AFTER a drive to the gas station.

If it's sitting in the driveway, and gets hot, then there IS presure, and is supposed to be that way. If the car is not running the fumes can't be vented into the intake, they'd just leak out to atmosphere and defeat the whole purpose of a sealed gas cap.

 

I agree with the blocked lines.Mine had excessive tank pressure until I cleaned / replaced the lines to the canister.It has some pressure now but nothing like it did before. The steel line at the rear wheel is a good spot to fill with rust.