dr bob

Jim C's '78 developed a fuel leak around the tank bung after an afternoon of warm-weather stop-and-go driving. Of course, with the covers off, the pump loose and sitting up on the lift, no leakage at all. [Scratches head where hair was previously able to grow...]

I was thinking that the tank was under pressure from fuel heating, so started looking for a tank vent valve from the charcoal canister to troubleshoot. In the actual car though, the plumbing around the canister and to the engine is different from what I expected. There are two hoses from the canister to the engine bay. One is from the bottom of the air cleaner housing, and appears to be there for filtered air to flow through the charcoal, sweeping fuel vapors to the intake via a vent valve. But the hose that I expect to go to the engine via a vent valve is cut off a couple inches inside the fender wall in the engine bay. I don't see where it would connect to the intake system.

Can any of the OB owners/gurus share some guidance on what we should be looking for on tank venting to the intake system?

TIA!

GlenL

I think you're half-way there. Seems that someone has cut the inlet line to the charcoal canister.

The tank has a vent on the top of the main section. A hose runs through the body fro it to a connector mounted on the filler. (Am I the only person who thinks the tank looks like an elephant's head with the trunk up? Have I watch too much "Dumbo?") From the filler, a hose runs to a hardline that carries the vapor to the front of the car.

That hose from the vent is a real PITA when removing and installing the tank. It's one of those bits that seems reasonable but is not manufacturable.

Maybe the line underneath is crimped? Or maybe it leaks when the tank gets hot and the pressure isn't really the factor. If you, or Jim, are lucky, the strainer will unscrew nicely and a new gasket will fix the issue.

dr bob

Thanks Glen. We'll likely pull the canister and try to blow through the rear line to the tank to see if it's clear.

Still open is the issue of where the line from the canister to the engine bay ends up. We have the (rear) one of the two connected to the air cleaner housing, but the other is cut a couple inches into the engine bay.

The Deputy

There https://rennlist.com/forums/928-foru...ived-54.htmlre three hoses on the charcoal canister.

One comes from the fuel tank, bringing vapor from tank to canister.

One goes to air cleaner housing, bringing vapor from canister to intake housing/combustion chambers.

One goes into engine bay and is cut short and open to atmosphere (approximately three inches long, after passing through inner fender), drawing fresh air into canister.

#107 (picture seized off the internet by me through illegal process, so divert eyes unless you want to be involved in the pending lawsuit...lol)



#225 (please disregard hilly-billy modification to hose plumbing, it has been corrected, but you can see short hose beneath washer fluid filler neck)



Much discussion in the #107 topic about these hoses and routing, right around the 794 post.

Link: https://rennlist.com/forums/928-foru...rrived-54.html

Brian.