My charcoal canister lines are worn out. I do not want to use it anyway, If I eliminate it and cap the line to my gas tank will I have to get a different gas cap ? What do I need to do ?
I do not want to change gas caps, mine is original,

 

You would need a vented gas cap, and you need to run a vent line--one of those canister lines--to a high point above the tank away from the engine compartment.

 

THANK-YOU.........IS MY ORIGINAL CAP VENTED ?????? I THINK IT IS.........
IN THE FUTURE I PLAN TO ADD A fuel regulator and will need a return line to tank. I plan to use the steel line currently on the canister now, the one going back to the tank if it is large enough.
THANKX 4 THE QUICK REPLY

 

Now It seems I must have a non-vented cap, but is the line from my tank to the canister allowing air in to the gas tank? The top hose with the asbestos lining is gone. I do have 2 lines attached still but forgot where they go, I think one goes back to the tank, I do not remember which one goes to the tank & I hope air is not getting in my tank to create moisture in it !!!!!!!!

 

There is a recent thread on this with some illustrations linked. I will try to find it tomorrow.

 

I do thank-you.........I did read about this many moons ago, maybe here, not sure. I have lots going & still have a little troublr breathing so I do not get near as much done in a day as I would like !!! so u finding that will help me greatly.......... Thankx...a lot......

 

This is the one I was thinking of, and it doesn't cover your truck. The evap stuff will be similar, and may help sort it out. (EDIT see below)

https://www.ford-trucks.com/forums/1...ual-trans.html

(illustrations and links are in posts 8, 9 & 11)


I do not recall looking at anything for a '71. I will try to search that out again tomorrow.

EDIT: The illustrations are here, w/ or w/o evap. You can see how the lines run etc. Seems if you had one of the lines run as a vent you could keep your non-vented cap. Be sure to NOT fill up all the way, but you knew that.

https://www.fordification.com/tech/schematics_e.htm

 

85e150 I do thank-ypu
I did a little research here and found that the canister does not affect performance & is good for the environment. I am very concerned about the ozone.
I will eventually add a fuel return line. Now I believe there will not be any fumes to be concerned with because the system will be closed !!! Of course I could b wrong. I will check into that more thoroughly. I will read your post tomorrow, I skimmed over it & the information looks like it will help understand how to add a return line the easiest !!! So for now I do not know if I will keep canister or not but your links & information will help greatly either way...............~~~ thank-you very much ~~~

 

Using a charcoal system is a good way to reduce the smell of gasoline especially with regards to somerhting like a hot summer day with a half full gas tank.

You want a sender with 3 ports, a fuel outlet, for your fuel supply, a fuel return ,which comes back fro mthe pump(THIS WILL REDUCE FUEL TEMPERATURE AND HELP WITH CARBURETOR-END smells/soaks/starting issues) and then a vapor line which usually runs all the way up to the front of hte vehicle and then plumbs into a canister which is also mounted higher of course.

on an old carburetor setup, I believe having this feed into a vacuum inlet at a specific time, I believe temperature vacuum switches may have been used for your original setup, and it may have only done so under acceleration if it did use a temp switch. this would prevent it from drawing the vapors at a cold startup possibly riching it too much or having it just draw at idle increasing rpm and stuff.

I could be wrong, but newer vehicles use a solenoid which allows the engine to draw those fumes when a computer says its okay, but thats getting into stuff I cant say confidently, so I will stop there.

The use of this setup would need a sealed cap becuase the fumes need to be pushed toward the canister not find their way out the cap. If you want to help your setup even more, heat shielding the gas tank from the road (skidplate could do double duty) and alsl wrapping the fuel lines/keeping away from exhaust can help on this matter. A properly running engine will have a non-gassy smelling exhaust and cat converters obviously help that even more.

The gasoline today is more apt to get vaporized with temperature (volatility I think?) and that means the same perfornance 30 years ago would be worse today all things equal on the truck(for smells)
So it may need more canister or something else may help too, but thats just a lot of the things I believe to understand decent.

I dont use my gmc on the road but it runs with a edelbrock, no regulator, timed by how the engine ran (havent took a light to it yet) the truck has a factory send, return, vent lline sender with a axle vent valve pushed into the vent with a vented cap. the truck had HD emissions and the charcoal system was not used for that. I would say it only smells gasy If its for example cold startup and then I dont let it get warmed up, thats prob the fuel bowl or maybe the timing/afr not being ideal. But i also do not use ethanol gasoline, nor do I drive on asphalt.

 

AuroraGirl u must b a mechanic I know lots about engines & I did not understand 1/3 of what u posted I do believe it will help I just need to read it slowly, I thought I was reading engineering almost.......... U must b a mechanic...........

 

no im a 23 year old unemployed emotional mess

but im glad I impressed lol..