Charcoal canister delete?

[85SubRestore]

I've gotta 85 sub and my charcoal canister is literally in pieces. Do I try and find another canister?

Or is it not worth it, and if that's the case what do I need to do to delete it as far as the gas tank vent line?

Emissions is not an issue where I am, as it currently has no cats, muffler and the smog pump is seized. The smog pump is expensive to replace and the charcoal canister seems difficult to find

Which as junky as having the canister looks Id rather delete it but if it is better for the engine to keep it I will

 

[SquareRoot]

Welcome. The cannister is worth keeping. It doesn't hurt anything but it sure keeps gas fumes from your gas tank ending up in your garage or other tight spaces. My 85 went south as well. I took one off a 87+ burb with TBI. It has less lines/ports on it than the carb version.

 

[squaredeal91]

Sounds like that will work we'll

 

[Scott91370]

I haven't had any issues with fumes and mine is in the garage all the time. I still have the canister and plan on installing it.

 

[1lejohn]

I installed a can on my truck. I bought it from Rock auto. I went with a simple 3 port type. They don't stock all the years. I had to make a bracket out of a hose clamp.

 

[75gmck25]

I recommend having a canister, but I’ve never found a complete listing for all the variations. It does not have vacuum on the canister all the time, so it needs a canister purge valve that allows the engine to purge the vapor out under certain conditions. However, the purge valve might be on the canister, next to the canister, or even designed as part of the carburetor.

For example, my ‘75 has a simple one port canister, and the purge function comes from a dedicated port on the stock Quadrajet. I have a newer carburetor, so I just ran the purge line up to the air cleaner and it pulls vapor all the time.

 

[Dixie Pride]

I have a 85K20 i bought new .It has farm tags so it is exempt from emissions. I took the convertor off years ago and had a shop de-smog my motor take the smog pump and all the stuff off .Only took an hour or so. Engine looks clean now and runs good.

 

[75gmck25]

The canister is not a “smog” device that affects how the engine runs; it’s simply a cleaner way to vent the gas tank. Earlier trucks had vented gas caps, which sometimes led to a mild gas vapor smell if you were near the back of the cab. The later trucks have a vent line running up to the vapor canister under the hood, so it traps that gas vapor smell. The canister has a vapor purge line and valve that periodically pulls the vapor out and sends it into the intake to be burned.

If you change the canister system you need to ensure your gas tank still has some type of venting. The fuel pump is pulling gas out of the tank and you need air entering to replace the gas.

 

[Randy and Easton]

@75gmck25 can you post a few pictures of what this should look like. We do not have this on our truck I guess a PO delete.
Easton did say the other day that when he opened the fuel cap there was a big “vent” of fumes. Like to address this issue if it will fix the venting issue.

Thanks

Randy and Easton

 

[SquareRoot]

@75gmck25 can you post a few pictures of what this should look like. We do not have this on our truck I guess a PO delete.
Easton did say the other day that when he opened the fuel cap there was a big “vent” of fumes. Like to address this issue if it will fix the venting issue.

Thanks

Randy and Easton

Where do those two lines go to from the tank, one obviously goes to the carb. Is the other one is a return from the pump or does it go to a cannister (or open air)? If it's a return line, then you need to be using a vented gas cap.

 

[Randy and Easton]

I can’t say we ever really looked actually. I’ll see if I can look today. Cap has the hole in base and side so I’m thinking it’s vented however the issue E told me about the other day May indicated cap is bad? Thoughts?

 

[SquareRoot]

I was having a similar issue. when it got hot here (100+) I could shut the truck off and hear the tank make that "popping sound" when metal expands/contracts. New tank, recently converted to EFI. So one time I looked under the truck and could actually see the tank was expanded in the brackets. wow, so I loosened the cap slightly and it blew hot air out for a good 15-20 seconds! I was dumbfounded. So I did a bunch of research and discovered that "vented" caps are only vented one direction. They let air in but not out. But that wasn't my issue (or possibly yours). I plan to just drill a small 1/8 hole in my cap but have been too lazy. I have been keeping the cap loose enough to keep it from sealing and eliminated the problem. Apparently, the cannister does not have enough capacity to absorb two 20 gallon tanks worth of expansion which befuddles me. I have tested the valve on the cannister with a vacuum pump and it works as intended yet the tank still builds pressure.

 

[Randy and Easton]

Thanks @SquareRoot , i will do that today, and look forward to others responses and I will crawl under later and see where the other line goes…

 

[Randy and Easton]

Well, drilled a small hole through cap and a small vent hole on cap handle. Traced the lines from gas tank and lo and behold, we found a line that just ends on drivers side by the brake proportioning valve. The line was just cut and not capped when E bought truck. One time last year when it was parked nose downhill we noticed what looked like transmission fluid draining out of it so E put the cap you see to prevent whatever it was from draining. E never followed up on it at the time.

So our question is, on the 1976 C10 with 350, did the charcoaled canister mount on the front clip or on drivers side inside fender wall? I can get another canister and attach it. I assume that we just use a vacuum port off the carb to complete the system?

Randy and E

 

[Bextreme04]

Well, drilled a small hole through cap and a small vent hole on cap handle. Traced the lines from gas tank and lo and behold, we found a line that just ends on drivers side by the brake proportioning valve. The line was just cut and not capped when E bought truck. One time last year when it was parked nose downhill we noticed what looked like transmission fluid draining out of it so E put the cap you see to prevent whatever it was from draining. E never followed up on it at the time.

So our question is, on the 1976 C10 with 350, did the charcoaled canister mount on the front clip or on drivers side inside fender wall? I can get another canister and attach it. I assume that we just use a vacuum port off the carb to complete the system?

Randy and E

That's the vent. Mine has the same. The original line would have gone to a rubber hose that would have gone to a vapor canister mounted to the core support on the driver side there. The picture of your sender shows you have from left to right in the picture, fuel feed, fuel return, fuel tank vent. If you aren't going to add a charcoal canister back in there, I would add some fuel hose that goes up to the top of the core support and then loops all the way back down to the bottom of the core support and then put one of the wobble vent valves that will keep any water from going into it. The big loop up to the top should keep the fuel vapor under control and still let it vent out any pressure if it needs to.