Vapor Canister

[PHOENIX]

I have had problems with my truck smelling like gas after shut down.
It takes about 20 minutes, then the smell is extremely strong.
I wouldn't even think about having any open flame near the truck.

I traced the smell down to the vapor canister.
For those of you who don't have the emissions equipment, please consider yourself very lucky. Emissions components are the majority of the problems I have had in the last few years. The required emissions components also considerably raised the cost of the exhuast system.

I get out my shop manual and decide to start checking the vacuum lines to the canister.
I start with the fuel tank line (fuel tank vent hose).
The inside of the line appeared wet. I attached my Mityvac and tried to apply vacuum.
"Apply 15" H2O pressure to the fuel vapor line"
"Observe for excessive loss of pressure."
Well the line will hold no vacuum. So it appears something is wrong there.
What do you suggest I do?
I plan to trace the line and check for leaks along the way.

I stopped testing the lines there and decided to remove the canister.
I suspected it had filled up with gas. I had my carb flood a while back and
I believe the fuel flooded into the canister.
See attached images for the 12+or- onces of gas I drained out of the canister.
Also some small black rock type things came out, I assume this is the charcoal.

I understand there are some filters and charcoal elements inside the canister.
The service manual says to pull the filter out from the bottom.
They didn't design this for easy removal, or maybe no removal.
I believe the bottom "cap" is glued onto the canister wall (cylinder).
The bottom also has indents for tightening the cap only, nothing for removal.
I remember reading on here somewhere about this, I believe it was Swervin Ervin that had some issues here also.

So here are my questions:
Do I even need this canister for emissions "sniffer" inspection?
How do they check this canister?
It looks like they only pinch a couple lines and verify they are connected.
What if I put ball bearings in all the lines so they dont do anything, but appear to be hooked up?
Or should I get the canister open and replace the filters and possibly the charcoal elements inside?

thanks,

[PHOENIX]

Nobody knows about these vapor canisters?

[EricS76]

I don't know about AZ, but in Texas It only needs to be there to pass a visual inspection in counties that do not have emissions testing. In the emission testing counties, I do not know. LMC sells the canisters and filters if you want to replace them.

[Phuloi68]

I have tried 3 times to get one of these canisters like your pictures open and have ruined each one. There was the charcoal media and filter. But ain't no way of opening them and then closing them without destroying them.
I have seen a vapor canister from a 79 that had the filter on the bottom you can change. It is smaller then the one you have pictured but still has 6 ports.

[swervin ervin]

I agree Eddie. On my 85 I tried (unsuccessfully I might add) to open my old one up and ended up ruining it. I bought a new one from GM. It's not on the truck now though. They stopped the sniffer last year but still have visuals. I can get it passed with just the visual. I know some folks who will give me a sticker and never look at my truck. I'm sooooo glad all that emissions crap is off my truck.

[Bowed]

Don't block it . They are going to pinch off 2 lines -the one to the carb and the one to the gas tank return and then apply one pound of pressure . They are making this test for leaks and it will not sniff the canister . Make sure your gas cap is good --it's a common failure .

[PHOENIX]

Bowed, i dont understand exactly what you are saying.
When they pinch the lines aren't they checking for leaks between the
canister and gas tank? If so why would it matter if the canister is
non-functioning? These things are like $80, even more im sure from GM.

I do need new gas caps before I go back (Sept. 06).

[817shadetree]

So in texas it only needs to be there cause im having the same smell also but some of the lines where it needs to go I dont have. My truck has a different engine and intake with no egr on it.

[EricS76]

In Texas it needs to be there and at least look like it's lines go to something. Don't leave open ports on it because it may make them want to look closer at it. Of all the inspections I've had done, the inspector has never physically touched anything under the hood except a battery one time to make sure it was secured. I've seen them look under the hood for 5 minutes, and i've seen them look for 5 seconds. It all depends on the person inspecting it.

[davidh]

I just had to have a carb rebuilt cause it sent chunks of charcoal crap into the carb, ran like crap too.

[PHOENIX]

My truck is running rough right now, even without the canister.
I don't know what the problem is.

Does anyone know the deal with the canister connection as far as sniffer test goes?
I can make it look like its working. but if it has to function to pass sniffer, Ill have to spend some money.

[DroppedZ84]

I actually got rid of my vapor canister, when I put the fuel cell in..but soon, after hating the smell of gasoline, I put it BACK on, and ran the vent from the cell (using the stock hardline) to the TANK port on the canister, and then ran it to the carb (using the stock hardline, again) from the CARB port on the canister...I have no idea why it would need more than 2 ports...It REALLY doesn't do anything..OTHER than keep that crappy smell out..

[PHOENIX]

Am I correct in thinking the gas fumes from the tank are sent to the canister through the line and the charcoal absorbs the fumes and eliminates the smell and fume pollution? When the motor starts up it sucks up these fumes and combusts them?

Thanks,

[swervin ervin]

Yes, you are correct Eddie. The charcoal canister does nothing to hinder the running of an engine in any way. It just looks like crap with all the hoses going everywhere in the bay.

When I removed all my stuff, to keep the smell of gas to a minimum I removed the hard line coming from the tank to the canister. I now have a filter for a vent at the tank switch where the line came out.

[Bowed]

Originally Posted by PHOENIX

My truck is running rough right now, even without the canister.
I don't know what the problem is.

Does anyone know the deal with the canister connection as far as sniffer test goes?
I can make it look like its working. but if it has to function to pass sniffer, Ill have to spend some money.

Like I said in my first post Arizona emissions will " NOT " sniff test the canister or canister lines because it is strictly a pressure / leak down / visual test . I myself would leave it alone just in case blocking it off affects some other part of the test / readings / or whatever . If you are still worried about it when you go in September , dry the canister out and then put it back in just for the test . If I can make a suggestion , try disconnecting the carb to canister line and run that line into a bottle to see if the carb dumps gas into the bottle .


.

[PHOENIX]

Thanks guys!

Not a bad idea Bowed. I guess Ill hook a canister to both lines from tank and
carb to see if either catches liquid gas.