I'm new to the Forum... I guess I jumped the gun with this post before introducing myself. 36 year old fella up here in the NW. Got a 69 camaro. Had one in high school that I rebuilt/restored, and then got stupid when I got married and sold it. So, a few years ago, I got another one. Here is the problem I'm having with it...


Howdy...
I've got a 69' Camaro with a 454.
Note 1: Over the past year or so, on occasion, I will run the car to town and back, and when I shut it off, it doesn't shut down cleanly, then after rattling around for some time, it finally shuts down and spews a lot of fuel down the carb (for about 30 seconds).
Note 2: Apparently the previous owner had backed into something to the point where the gas tank had a small dent in it. Last week, I took the car to town, and when I got back, I noticed a small crack in the gas tank where the dent had been. I shut the car down (note 1 above happened). I looked under the car at the gas tank while opening removing the gas cap... there was a mass amount of pressure released and I could visually see the tank supress back into shape where the crack was in the tank as if it was imploded/expanded abount an inch or so.

My question is this... Outside of temperature change, or gas fumes from driving around town... what would create that much pressure in the tank? Should there be some kind of vent/vapor release out of the sending unit? The gas cap I have is vented (one way only ~ into the tank). How does the pressure escape the tank to not force fuel into my carb after I shutdown the engine?

Thanks in advance
Terry

 

Welcome to the forum, post your question up in the 1st gen tech section if you haven't already.