fuel evaporative emissions control system

[KTM2FORD]

just pulled out my main fuel tank, to replace it. before i do, i was curious if anyone had some advice or knowledge: it's a 1970, so doesn't need to be smoged, the carbon canister doesn't have a line running to the carb, and for what I can tell isn't being used anyway. i have the service manual and it shows with and w/out the emissions system but talks about a vented fuel cap. I was going to purchase a standard tank form tom's but didn't know if I also needed anything else in order to remove the emissions system...do i also need a filler neck without emissions control? if not can I just plug the two lines coming out of the tank?

thanks!!

 

[mtp71174]

what I ran across is the later model caps that fit your filler neck are not vented because of the emission systems. if you find one great if not use one of the lines and run a hose up the filler neck loop it back on itself with a tie strap and put a small filter off a lawn mower or such on it Make sure the loop is tucked up higher that the filler neck. It is now higher than any water you should cross through. The proper epa way is to run that line to the carbon can and one line from there to the manifold.

 

[PaveBronco]

Easy to pick up a late model charcoal canister from a junk yard, and plum it in. The vented caps are vented in not out to stop negative pressure building up in the tank and affect the fuel flow out.

 

[KTM2FORD]

Just to be clear i don't want the emissions system in there.

 

[Seattle66]

I basically did what mtp71174 described. I ran a hose from the tank vent on the side of the tank up along the filler neck and put a small lawnmower fuel filter on the end. I made sure to loop the vent hose over the top of the filler neck where it attaches to the fender. The only drawback is when I was filling the tank the first time I topped it up too far and fuel actually ran out of the little filter. Overall it works well, but it still seems a bit jury rigged to me.

The new tank I put in was from TBP.

 

[PaveBronco]

Just to be clear i don't want the emissions system in there.

It’s not really an emissions system, ok well it is but not one of those crappy things that takes power away or anything dumb like the EGR system. Its more of a safety thing, the charcoal absorbs the fuel vapors and then when you start the truck up the vapors get sucked into the engine. It stops vapors floating around. Having said all that, lots of guys run the filter method and it works ok.

 

[lca'73]

Sorry to semi-hijack here, but I actually want to put mine back on. It was on before my resto and I didn't have a clue what it was so I didn't pay attention to how it was plumbed from the tank to the collection container - charcoal - carb. All of the links to drawings that I've found have since be deleted or are no longer correct. Does anyone have current working links or drawings they can share to show what lines go where and how this systems hooks up? I have searched here and googled every wording I can think of and I must be using just exactly the wrong search term because I can't seem to find it.

Thanks!!

 

[904Bronco]

I added a Charcoal canister on my 68 just to prevent gas smells in the garage and I personally do not think all emission items are bad... but that is just me. I installed mine based on what was on my 77. A vent line off the top of the rear tank, to metal tubing that I bent up and ran along the the outside of the frame. It runs up to a canister that came from a Fox body mustang 88-92. But Ford used the same style in a lot of years. The fumes, if any vent out of the canister, but it would be easy to hook it up to an air cleaner or carb if that was desired.
Rubberized clips are from NAPA, metal fuel line and standard fuel hose can be found anywhere.

 

[B-man]

I have a 73 Bronco, 2 tanks. I want to get rid of the front tank. I am going to upgrade to a Toms Bronco Tank next year. For now, the rear, although small, will suffice.

I also know that my evap system is not all there.

My main concern and what I am hoping to eliminate is the canister this behind the drivers side door jam. It has hoses going to both tanks, or from both tanks.

So, when I eliminate the front tank, it is safe to assume I can eliminate that plastic canister inside the truck?

 

[DirtDonk]

It's not really related to removing the front tank. It can be removed independently of either tank, but it obviously defeats the system as a whole. Since you say the system is not completely connected and is not functioning anyway, then removing the condensing tank from inside is just a matter of removing it. Whether you keep both tanks or not.

The condensing tank in the cab takes vapors from both tanks, then returns any excess liquid that condenses back to the rear tank. Hence the 2 hoses to the rear tank and only 1 to the front tank.
It's mounted higher up than the frame mounted charcoal canister in order to avoid liquid gas getting all the way up front and contaminating the charcoal media. The newer style of charcoal canister reduces the need for that in-cab part.

You'll be left with the two lines to the rear tank that you will have to decide what to do with, but that should not dictate whether you can or can't remove the in-cab tank either. Either do what the others said with a filter, or whatever seems to work for you.
You can cap one off and use only the one remaining, or use both. I would run both to the filter rather than one though, just for better venting.

Personally I'm in the camp of keeping the system, but preferably by updating to the newer style like 904Bronco showed in the pics (which is now my Bronco) which mounts higher up so you don't need the in-cab part.

Up to you, but if it's going to be parked indoors you might consider updating the system. While some have reported not having any issues with fumes in the garage, more often than not they do. If it' sparked outside that won't really matter.

Paul

 

[sprdv1]

What the ^^^^ man said...

good luck