Fuel Tank Vent / Fuel Smell
I recently added a Holley Terminator system & Aeromotive Stealth tank/pump combination to my 67. Since then, I have been battling a strong fuel smell any time I drive it. (not sitting in the garage) I had no leaks and the system is tuned pretty close, so it is not running excessively fat. I finally narrowed the issue down to the tank ventilation.
I am running the stock vented gas cap. The tank had a vent nipple built in(near the sender) and the Aerormotive sending unit had an outlet for a vent hose. I had been using the nipple and sender outlet joined together and then ran to the area above the rear end housing. This did not seem to be working because of the elevation in that area of the floor pan is not much higher than the area where the hoses exit the fuel tank. Add in exhaust pipes, and there is not much room to work with.
The lack of vertical incline of the vent hose let fuel to slosh up into the hose and filter that was on the end..… This was causing my fuel smell. Even when it completely drained back into the tank, the system still vented directly into the atmosphere and caused issues for me as the fuel heated up.
Rather than buying one of a expensive fixes you can find on the Internet or scrounging around a salvage yard, I decided to scrounge around my garage instead…
The following is what I ended up putting together. It works great so far!!
I had a leftover coolant overflow tank that I decided to turn into a charcoal canister. There were "in" and "out" nipples. The "in" had a tube attached that went to the bottom of the tank. I used steel wool on both ends of the tank to hold the charcoal pellets in place and to allow airflow, then filled it with activated charcoal pellets.
Next I drilled a hole in the very upper part of the filler neck (on top) about an inch from where it goes through the body panel. I offset it just a bit to allow for clearance of the trunk key shaft.
I installed a -6an bulkhead into the hole, then attached the -6an 90° female/female fitting with a -6an/ 3/8" hose nipple to it to direct it away from the trunk lock area. and to allow for easier disconnection in the future.
I connected that set up, using a 3/8 rubber fuel line to the nipple that goes to the bottom of the filter tank. From the filter tank exit nipple, I ran a 3/8 hose to a hole that I drilled in the trunk floor beside the filler neck.
Capped the vent outlets on the sender and the tank, leaving only my new filler next vent hose.
No more fuel smell while driving or while parked in the closed garage. No pressure on the fuel cap when removing it. Another reason I know that it is venting/filtering is because it gets just a bit warm after driving the car for a while.
All in all, it was a successful project... especially for my garage...!!!!
Hope this helps someone....
Coolant overflow tank (could anything similar)
-6an male bulkhead fitting
-6an female/female 90* fitting
-6an male to 3/8" hose nipple
000 steel wool