1980 Buick Regal Expanded fuel tank - excessive gas vapor

[HutchAuto]

1980 Buick Regal originally my grandfathers - can with a 4.3 litre pontiac engine. Has a fuel line, vapor return line and evap retrun line. evap line pluged as chrcoal canister removed, vapor return line originally connected to fuel pump but Chevy pump has no return line. Leaving this line open results in gas vapor filling up my garage - pluging this line results in an expanded fule tank or when removing gas cap - a ton a vapor blows out. Cap is vented already. Having worked on many G bodies at my shop the issue is clear - however the resoltion is not. On my 65 goat it has the fuel filter with a vapor retrun on it so was considering installing this. My question to anyone out there who has one of these built with a factory Chevy motor is how did you handle this situation? In the GM shop manual for a Chevy motor equiped one - it does not show a vapor return line but only the fuel and evap line - either they ommited it or none is required. Again, having built many of these - this is the first time I have ever encountered this issue - figures its my own car. Any help would be appreciated.

Thanks,

Jamie

 

[TURNA]

Would putting the charcoal canister back in solve the problem?

 

[HutchAuto]

possibly, however, there is now a dual battery in its place for the competition stereo system. its just odd as i work on many these cars in my shop and never came accros this issue before - usually plugging the evap line is it - also work on many A body's (have a few myself) and do not ever recall this happening. was thinking it must have happend to someone else and they, of course, would have the answer. Thanks.

 

[84GP455]

I have the same problem ever since i changed my gas tank. There is a lot of vapor release when i remove my gas cap which is also vented, and my gas tank makes noises when it expands on a hot day not sure why. I only have 2 hoses coming off my sending unit, it doesn't seem to have a hose for a vent. maybe installing a vent of some sort so the gas vapors can release will correct the problem?