Fuel tank question

[CRAIG]

Is it normal to have a release of pressure when you open the filler cap when tanks about 1/4 full?

I have the vent tube on filler neck connected to the 2nd outlet on sender unit, is that correct?
On 69 Charger

[steveo]

Is it normal to have a release of pressure when you open the filler cap when tanks about 1/4 full?

I have the vent tube on filler neck connected to the 2nd outlet on sender unit, is that correct?
On 69 Charger

nope ! that's not correct
the filler neck vent , is just that it should be left open ,! or should I say , it should be vented to the out side air , the factory set up , was to run it into the rear drivers side frame rail , & that was it , IMO not a good idea , so what I done , was extend the vent tube with a piece of suitable size rubber fuel hose , so its just sticking out of , one of the factory holes in the frame rail , under the car , the smaller 1/4 nipple on the fuel sender , is for a vapour return line , from a vapour separator , if you have one , if you just have a single fuel line , this 1/4 nipple on the sender unit should be plugged .
im assuming that you have the stock OEM , 440/426 , 3/8" & 1/4 " sender.

below is a picture of the stock set up , you can see the vent tube passing through the trunk floor , & exiting into the frame rail , if you copy the way the factory done it , make sure all your floor plugs & grommets are installed , other wise your smell fumes eventually . , this was the reason I lengthened the vent tube to exit through the frame bottom did not like the idea gas fumes inside the frame rail .

side note , have heard stories of a fuel tank imploding / collapsing or what ever its called , because of a blocked fuel tank / cap set up , never seen it my self
( most modern cars do not have a vented set up )

[CRAIG]

Though it was just a vent.

I was told to connect it to the fuel tank sender.
I always used to have it go into the frame rail, then I was told to connect it to tank sender.
I will put it back to how it was.

Cheers