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Can 30 year old charcoal canisters still be good?
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Author:  Sonic Purity [ Wed Feb 09, 2011 1:31 pm ]
Post subject:  Can 30 year old charcoal canisters still be good?
Greetings Everyone,

First, a big Thank You to everyone here, past and present, who has contributed knowledge and/or support in any way to/for this forum. I’ve spent many days once again over the past several weeks absorbing mountains of wisdom from this forum (via search and Subject line scanning), saving me from asking a number of repeat questions. (And yes, i did a few minutes ago once again donate what i can afford to Chuck to keep the board going.)

Life events forced me to suddenly drop work on Vanglorious (my name for my van) and my then-current threads on this forum two years ago. :shock: I still owe some answers in at least one of those threads, and i’ll get to it when i can. Long story, and this isn’t the time nor place for it.

******
I’m re-doing the whole fuel system, mostly on account of several episodes of old gas sitting in the system for a few years each time, though also age. I have already replaced all the rubber lines (with 30R9 fuel injection hose except for a 3/16" return line where they don’t make that size that i can find, so it got 30R7), visually inspected and pressure tested the metal lines, and more (again, a long story).

This van has factory dual charcoal canisters. There is no extant part number on either one (the labels faded/washed/etc. to nothing and/or fell off long ago). These are the type with the big purge valve tower in the center (vacuum control line on top, purge beneath it, vent with cover beneath that), tank vapor return line on the left, and bowl vent on the right (with the nipple openings facing the viewer). INTROL is the brand atop the purge valve cap.

I believe these canisters to be original to this 1981 van, which i purchased in 1989. I recall that they looked old/dirty at that time (when i was verifying the vacuum hose routing, which had been screwed up yet has been OK since 1989. I have checked it carefully several times).

I have tested both canisters, twice on separate days, according to Slant Six Dan’s test in this post: both canisters pass. Neither is blowing out charcoal - no problems with that. I smell/taste fuel (vapor, not liquid) when doing the test.

There are no known-to-me problems with the canisters, other than being 30 years old. Normally, i might assume all is well and move on. Yet, i’ve recently read that, after years of not being available,official Mopar-sanctioned and sold canisters have reappeared. Now, i’m not in any hurry to drop a couple Benjamins for new canisters… yet i do live in California with its stringent visual smog testing requirements, and in any case i do want the system working as intended! Further, some older posts on this board indicate that the activated charcoal ceases to work after som (unspecified) time, while other posts seem to contradict that and claim a long (unspecified) life for these canisters. I am wondering whether i should get replacements while they’re available… though i don’t want to throw away money replacing perfectly good parts.

So my questions are:
[list]* Is it possible for 30 year old charcoal canisters to still be fully functional?
* Are there any additional tests i can do (with typical home mechanic equipment)?
[/list]
I also welcome your general thoughts on this issue.

Thanks!

))Sonic((
Author:  lancer61 [ Thu Feb 10, 2011 12:09 am ]
Post subject: 
They can live for a very long time (so yes it might still be ok), but it can be pretty dead also after 30 years, it all depends on where the canister has been sitting for the last 30 years.

The coal doesn't go bad in itself, but if you get air/particles in there it can degrade the functionality of the coal.
Author:  65CrewCabPW [ Thu Feb 10, 2011 1:48 am ]
Post subject: 
If the charcoal canisters don't absorb much anymore, what, precisely is the "symptom"? Nothing. If properly plumbed, the system holds pressure in the tank and cannisters and once started, the vapors will be released into the air cleaner to be burned as the motor runs.

So, I don't really fully understand your concern about this. As long as they're there, you will pass physical inspection, and no function (tailpipe sniff) testing is ever going to be affected by them.

Today, most smog in California is naturally caused, by flora and fauna, sunlight, and heat. What little is going to be added by possibly leaking a little out of your EVAP system is of no consquence, and never will be. Put the hoses in if you have to comply visually, keep your car well tuned and properly adjusted in terms of carb settings, lots of spark, etc, and that will make vastly more difference than any slight emissions change resulting from charcoal that's now inert.
Author:  Sonic Purity [ Thu Feb 10, 2011 8:55 pm ]
Post subject: 
Quote:
If the charcoal canisters don't absorb much anymore, what, precisely is the "symptom"? Nothing. If properly plumbed, the system holds pressure in the tank and cannisters and once started, the vapors will be released into the air cleaner to be burned as the motor runs.
Makes sense… but then, why did they use charcoal in the first place? (Not debating/arguing at all… just wondering, due to imperfect understanding of all this.)
Quote:
So, I don't really fully understand your concern about this. As long as they're there, you will pass physical inspection, and no function (tailpipe sniff) testing is ever going to be affected by them.
Good to know. My initial post was likely worded poorly. Here are my goals:
  • * I want these systems to work properly, unless it is not possible (parts NLA) or vastly expensive.
    * I want to keep this van many more years. In California, with visual inspections + measurements. With this system working properly. Parts come and go. Cal. Air Resources Board-approved OEM canisters have been gone for some years, yet are (for now) available.
If this is still clear as mud, let me know and i’ll try again.

Appreciative of the advice (and welcoming additional and others’ thoughts),

))Sonic((
Author:  emsvitil [ Thu Feb 10, 2011 10:23 pm ]
Post subject: 
I don't think the charcoal actually goes bad in the canisters.

I think the canisters fail mechanically, rust out, valve failure, etc...
Author:  65CrewCabPW [ Thu Feb 10, 2011 10:42 pm ]
Post subject: 
Quote:

Makes sense… but then, why did they use charcoal in the first place? (Not debating/arguing at all… just wondering, due to imperfect understanding of all this.)
A hollow can will hold a microscopic amount of vapor until the pressure rises to balance out. Fill it with charcoal and it holds a LOT more molecules of vapor without the same rise in pressure.
Author:  Rug_Trucker [ Fri Feb 11, 2011 2:33 pm ]
Post subject: 
First exwife's Isuzu PU sucked slivers of crap into the bowl and messed with the needle/seat. I put a fuel filter in line and fixed that.
Author:  rooster [ Mon Feb 14, 2011 11:52 am ]
Post subject: 
Yep. I can testify to rug truckers reply. Had this happen to me on a
78 D100. Its nasty. Putting a fuel fil. in the line would be an excellent
idea.
Rooster
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