Noticed a gas smell occasionally after a long run. today.. just a 25 mile tow with a 16 foot car hauler trailer with a chevy Malibu on it. Stopped at the shop to drop the car off.. smelled gas again, again.. looked under No gas leaks. So i open the rear tank filler door.. STRONG gas smell. Loosen the cap.. hear hissing, gas fumes come out.. so I take the cap off... took several seconds to finish venting with NO CAP.. for the pressure to fully vent!! 8 to 10 seconds total time audibly venting fumes from loosening cap and removing at least! What the heck is causing that??

91 f150.. 5.0.. AOD... only has the REAR fuel tank.. front one was removed and lines capped etc over that tank valve problem those trucks had before..

any Ideas what could do this?? the tank was real low on fuel when this occurred.. fueled up right after. Thanks.

 

I'm having a brain fart on the actual name of the part, but there should be a vapor recovery valve/solenoid somewhere around in the engine bay. When the truck is warm and running I think you can here it clicking with a mechanic's stethoscope.

Or the canister could be blocked (full of gas) and not be able to let it vent properly.

If Steve83 pops in he will have all the pictures and tests to solve your issue.

Sorry about being so vague............but the those brain farts seem to come more frequently these days.

Good luck

 

If the tank was low, and it was a hot day, it would be normal for there to be some pressure in the tank. Gasoline is volatile.

The filler neck has a baffle, which is why it took a while to release all the pressure. It's there so gas doesn't spray in your face.

But it does sound like yours had too much pressure. Is your evaporative emissions system intact & functioning? Click this, read the caption, & follow the links: