Leon Speed

Ever since I connected a new charcoal cannister (new design, see https://rennlist.com/forums/showthre...light=charcoal), my fuel tank doesn't vent well. Some high speed driving on a almost empty fuel tank resulted in a partially concave fuel tank

I tried to understand the vent system, but don't get it. Two questions:

See first diagram below: the way I understand it, the fuel vapors from the fuel tank get drawn through the expansion tank to the engine. So if the vapor flow is from the tank to the engine, where does the tank get equalized?

Second diagram : what is drain #6 connected to?

David L. Lutz

I installed the "new" design using option "B" in the thread you list and don't seem to be having problems. However, I have only driven the car about 200 miles. It's back on jack stands getting a Murf Sage III.

I will watch my tank and post if I have issues, but all looks good for now.

Note: When my canister went bad charcoal was in all my lines therefore I replaced all lines, and #40 & # 8 in the 1st diagram.

#6 drain is the overflow at the filler neck. It hooks on to the rubber boot and just runs down under the fender.

Leon Speed

I did about 800 miles since and some long stretches.

I traced #6 down to the drain behind the rear bumper (#24 and #25) in the first diagram. Is that correct or somebody home plumbing?

soupcan

Found this diagram, maybe it will help.

David L. Lutz

On my 87 #24 & #25 vent down at the rear bumper at about the center of the car, maybe a slight bit to the drivers side. AND #6 in the 2nd diagram just runs stright down from the fill neck.

Leon Speed

Ok that makes sense. Soupcan's diagram confirms it. Looks like I have to check if #24&25 are connected correctly. I connected the charcoal cannister the way it was discussed in your thread David, but maybe #24&25 are blocked further along the way.

Still I don't understand how the tank gets equalized if the vapor flows one way. Does outside air flow through the same line the opposite way?