Emissions canister thing...

[philo_beddoe]

How dows this thing come apart? I want to remove the guts and make it "look" like its functioning. I know i can get a new filter, but i dont think it will make the world any cleaner.

[Dr_Snooz]

I think it's a sealed unit. You'll have to cut or break it. I'd be interested to know if it's a carbon block inside, or just granules.

[zieg85]

Unhook it and see if you can stand the gas smell as you walk by your truck or how bad your shed is going to smell like raw gas.  GM put it there for a reason, I'd keep it if it were me.

[Dr_Snooz]

Ditto, but I thought it would be politically incorrect to say it...

[big_al273]

Unhook it and see if you can stand the gas smell as you walk by your truck or how bad your shed is going to smell like raw gas.  GM put it there for a reason, I'd keep it if it were me.

the other thing is that since your fuel tank vent will be open to the atmosphere you may find your fuel absorbs moisture from the atmosphere possibly effecting performance and you will lose gas to evaporation with an open fuel system

[VileZambonie]

There is no practical reason to remove the charcoal canister. Even for hot rodders who don't want ugly stuff in their engine bay, it can easily be relocated to a safe place under the vehicle and out of site. Your fuel tank needs to vent for refueling, consumption, change in temperature/pressure etc. If yours has failed you can get a replacement unit.

Why do you want to take it out?

[philo_beddoe]

There is no practical reason to remove the charcoal canister. Even for hot rodders who don't want ugly stuff in their engine bay, it can easily be relocated to a safe place under the vehicle and out of site. Your fuel tank needs to vent for refueling, consumption, change in temperature/pressure etc. If yours has failed you can get a replacement unit.

Why do you want to take it out?

I dont want to remove it. In fact, i cleaned it up nice and painted the canister and bracket. I thought they get clogged over time and thus could cause some blocking of vapor exhaust, causing other problems. However, all gave good replies, so i'm leaving it alone. At first i thought it was just a stupid emissions thing they had to do back in the mid to late 70's. Then i thought i saw in a catalog you could replace the charcoal and filter, or maybe i saw that somewhere on this site,, either way, i'm keeping it factory original.  Thanks for the replies.

Ps. I will try to replace the disc shaped insulation type filter on the bottom. At some point mice picked at it a little. I believe that part can be replaced. Plus there is always this option:

[VileZambonie]

Just replace the canister as an assembly

[Dr_Snooz]

I don't think they clog. They just get saturated and stop absorbing fuel smell like they should. Basically, if it's bad, you're gonna smell it.

[philo_beddoe]

It'll be fine, i dont smell anything at all. If i end up replacing anything it will be the assy as vz stated.

[Henry]

Hi Philo:
The canister you guys have been discussing is the ECS (evaporation control system) canister which is part of the suite of emissions parts to control fuel tank evaporation of fuel into the atmosphere. First measure was the introduction of the pressure-vacuum gas caps in the early 70s...then they went further in the mid-70s by introducing the ECS equipment which also sends the fuel vapors into the engine to be burned. (My 76 3/4 ton does not have this equip and associated cannister...only the pressure-vacuum gas cap.) I believe the cannister is a charcoal element with a filter. My service book says the filter element should be replaced every 24,000 miles....so it probably can be removed from the bottom of the cannister, I am guessing. I think I have seen a filter for sale in one of the restoration catalogs... This system can cause drivability and starting problems if it gets clogged up and causes a vacuum inbalance in the fuel system as Vile has mentioned. Clogging of the cannister is not likely but if the filter has never been changed, I would do it or at least clean it. The item in the system that does need to be checked and most likely can cause the aforementioned problems is the purge valve which should be mounted on the engine...if this guy gets stuck or clogged, you will get some weird fuel problems like non-starting, fuel starvation, too much vacuum in fuel tank(s). If you decide to remove the cannister, you should remove the ENTIRE ECS system to prevent weird problems...and this would be too much trouble(there is also a fuel separator somewhere down by the fuel tank) and not buy you any improved performance or fuel economy...it would be easier to leave it all in place and maintain it (make sure nothing is clogged) as it really is not that much work.

[philo_beddoe]

Right, i decided to clean it up instead and i removed that lower filter disk that is replaceable. There is no gassy smell. But i will most likely replace it when i come across one in a parts catalog. Thanks for the reply.