Hey guys,
Glad I found this site. I bought a 1979 F-100 about ten years ago, gave it to a relative, and it has now been "regifted" back to me after sitting untouched for two years. So I've got my hands full getting it back on the road, but I've got a question. When I bought it ten years ago, I hired a shade tree mechanic to rebuild the engine. He took the liberty of yanking out several pieces of emissions components. ("Eh, you don't need that crap!")

While looking over the engine today, I noticed for the first time the rectangular vapor canister across from the alternator. Nothing attached to it. I noticed it because I followed the vapor line coming off the gas tank, and the vapor line is just sitting there under the canister uncapped and unattached to anything. This truck has always smelled heavily of gas. I'm wondering if I just run a line from the vapor line (from the gas tank) to the vapor canister (also called a charcoal canister, I think), would it elevate the smell and maybe provide other benefit? I believe a line also ran from the canister up to the air filter housing, but that housing was also trashed when the mechanic put in a four barrel carb with custom air filter.

If reattaching the vapor line to the vapor canister is correct, what kind of tubing do I use? Anything that will fit?

Thanks.

 

Welcome to FTE.

The fuel tank is connected to the vapor canister via (IIRC) hard line and a short section of hose. The charcoal absorbs gasoline vapors (volatile organic compounds) which are then evacuated by vacuum through a hose connected to the air cleaner housing and burned in the combustion cycle...the latter is like a metal foil tube. I understand a 3/4-inch ID version is available through NAPA Auto Parts.

 

Thanks for the response. So what I'm understanding is simply attaching the vapor line to the canister is not all that's needed. The mechanic took out the factory two barrel (with air filter housing) and put in a Holley four barrel, so I'm not certain at this point how to introduce a line from the canister to the air filter. Its just an Edelbrock 3" fllter without any way to attach. I've seen that metal foil tube, but I haven't seen a hose offered that attaches the canister to the hard vapor line.

I was just thinking that attaching vapor line to the canister would eliminate the heavy gas smell, but there would be nothing to evacuate the vapors from the canister. Wondering if that matters.

 

Yeah it matters... or else the vapors never get evacuated. If intending to keep the canister, then ya gotta get an air filter housing with the fitting for the metal foil tube.

However if ya don't need emissions testing, then delete the canister and trace back the vapor canister's line back to the fuel tank (or somewhere along its length) and plug it. You'll need to get a vented fuel cap so the fuel can expand and contract with changes in temperature.

 

You didn't say which engine so I just picked 302.
Here's an illustration of the evaporative emission control system from the Ford parts catalog.

 

Thanks Mike and HIO,

Yes, its the 302 V8 engine. Looks like options are to either find an air cleaner housing at a junk yard, or to cap/plug/remove the vapor line and vent gas tank through the filler cap.