Fuel Vapor Return Line Removal

[CORSAIR]

Do I need to use the vapor return line? Can I subsequently remove the vapor canister? All the other lean burn/smog equipment has been removed.
If I can abandon the return line should I leave it open to the air or cap it off? I'm assuming this acts as the fuel tank vent and should not be capped off because it could vacuum lock the fuel system, correct?

 

[M_Body_Coupe]

So I'm thinking you are talking about the tank=>vapor canister, yes?

I would say keep that in place, and even if you remove the canister (which we all agree is ecologically bad - not judging, just saying) you still need a way to vent the fuel tank.

Now having said that, our OEM fuel tank gas caps are venting as well, but they are configured to vent at a higher pressure, which means that they are only active when enough pressure builds up in the system that it approaches an unsafe level.

I say all this b/c this is where I'm coming from:

1) I have the tank=>canister line hooked up on my ride
2) I have the carb (TQ)=>canister line hooked up as well
- this does in fact work b/c with the correct fuel bowl vent setup it will prevent your carb heat-soak from pushing the fuel in the bowl fuel out of the idle/booster discharge ports, thus making for a nasty hot re-start
3) I do NOT have the canister=>TQ purge line hooked up
- which essentially means the canister is kind of a storage box for gas fumes, nothing empties it, but it also prevents that "whiff of gas fumes" hitting your face when you pop the hood open
- I do occasionally worry if I'm creating a little "explosion ready box" there, lol, I mean I think the bottom filter is slowly allowing the fumes to escape out, but I've never tested this, so maybe at the start & end of a cruising season I should actually hook the purge line up and just vent the snot out of that thing????

Does that help?

 

[AHBguru]

Never any good reason to tear all that stuff out, especially if you don't understand what it is or what it does.

The vapor return line functioned two ways - it returned any excess fuel to the tank, and it helped prevent vapor lock. It didn't always work - the return line itself was probably a little too small, and it usually corroded shut after a few years in service.

The old service procedure was to blow the feed and return lines out, then test for leaks/blockage. Then you'd repair it by either splicing in a new segment of line or an appropriate size length of fuel hose.

The emissions equipment was very basic - quite rudimentary by today's standards - but didn't actually affect power, at least with the '81-'89 cars. You gain absolutely no power by removing any of the emissions equipment, excepting 3 or 4 hp if you ditch the air pump and cap those lines (and cobble /configure the air line from the cat to the air cleaner, with a check valve salvaged from the existing system).