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Old 12-23-2005, 09:33 PM   #1
PHOENIX
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Emissions Vapor Canister (Evap. System)

Sometimes while driving the truck I smell some gas.
The real problem is after the truck has been turned off for awhile.
It really starts smelling like gas, big time.
If I park the truck in the garage the smell (fumes) are so strong you
can smell them in the house. Enough to clear out the house.
When I park in the driveway you can smell it in the house if the front
door is open. Its so strong smelling I wouldn't light a match anywhere
near it. A few times I thought twice about turning the lights on in the
garage.

I tracked it down to the vapor canister. No doubt the smell is coming
from the canister. All the lines are hooked up correctly. I am going to
follow some tests in the shop manual.

Has anyone ever had this problem?
Can I change out the charcoal inside the canister (filter?)?
Is it a dealer part?
Just looking for info from those who have worked on the canister.

Thanks,
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Old 12-23-2005, 10:07 PM   #2
ureckme
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Re: Emissions Vapor Canister (Evap. System)

Can't be just the canister, check all lines, and the filler neck, carb etc. Im sure you did check but the vaper canister when it goes bad doesn't make it smell real bad unless you have fuel coming from the tank in to the canister. Its a dealer part or go to a pick a part. Matt
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Old 12-23-2005, 10:57 PM   #3
piecesparts
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Re: Emissions Vapor Canister (Evap. System)

I believe that the fuel tank is vented to the canister when the vacuum is taken away (E.G. when the motor is turned off. The gasoline smell is common when this happens. However, I am betting that your carbon inside the canister is not in the best of shape and it appears that it needs to be regenerated or replaced.
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Old 12-24-2005, 06:03 AM   #4
fiream
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Re: Emissions Vapor Canister (Evap. System)

It's been a while since I fooled with one of these but I'll see if I can add some things to check.
1. Routinely overfilling the fuel tank (topping off) can cause this as liquid fuel can slosh and get into what is supposed to be a vapor only line and saturate the carbon. Made worse if you only use the vehicle for short trips as the canister never gets fully purged.
2. There is a valve on top of the canister that opens to purge vapors back to engine. I believe yours would still be vacuum operated. The valve may have failed or is not receiving a vacuum signal at the appropriate time. May be controlled through a TVS switch that isn't working. On GM's it's usually located in the thermostat housing.
3. There is a filter on the bottom of the canister that can be replaced. I've seen them completely sealed by undercoating. Could also be dust, mud, crud, etc. Has to be open for canister to draw fresh air through carbon during purge cycle.
4. Check condition of lines running to canister. If they are originals, look real close. Sometimes they crack on the underside where you can't easily see but the top looks perfect.
5. Check vac. line routing and compare to underhood sticker. Not uncommon for lines to get mis-routed during service and usually won't show up until long after.

Hope this helps some.
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