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Charcoal Filter Issues/2004 Xterra 4WD

2K views 5 replies 4 participants last post by  redjester 
#1 ·
Me and my rusty beach truck are back with another issue! Any info would be greatly appreciated fellas!
Thru the winter into spring I could no longer pump gas full throttle..pump would constantly kick off like it does when tank is full.
Summer came, truck would take gas like normal again.
3 weeks ago truck started kicking pumps again!
Filled up yesterday and as soon as I got home I could smell gas near the gas intake area. Could still smell gas this am..not losing any truck still has what it should.
Have read a few things about this happening when the charcoal filter goes bad, have had this truck since '06 and have never replaced it.
Any ideas or suggestions as to how to diagnose or any diagrams showing these areas?
Is this something I can change out pretty easy or something a shop will need to do?
Thanks for any help!!
 
#2 ·
The gas tank has two ports to know about:

1) The one you pour gas into to fill the tank.

2) The one that lets air OUT to make room for gas that's getting poured in/evaporating in the tank air, etc.


The charcoal can is on the #2 port, so that the air you vent outside the truck has the gas vapors/VOC stripped out so the exhausted air is clean/the stripped out gasoline can condense, and drain back into the tank, instead of being wasted.

If the #2 gets clogged (Spiders, dirt, a kink, saturated charcoal can, etc...) then air can't get out when the gas is poured in...

...and the gas in #1 backs up against the outrushing air. This is why you can pour gas in slowly enough to avoid the problem, as the gas going down and the air coming up CAN pass each other on the way past each other....there's still room for both.

When you pour in fast enough though, it might start OK, but, then the gasoline will even be burped back out of the filler by the escaping air.

If you are OVERFILLING the tank, it causes the can to be saturated with gasoline. In the summer, this can evaporate more quickly between refills, so, if hot the charcoal can recharge/dry out faster.

In the winter/when its cold enough, it slows the evaporation, so, it stays saturated longer...which = clogged longer, etc.

So, as your can RECOVERS in the summer, it means it is OK, but YOU have to stop overfilling the tank.

Overfilling can happen from squeezing every last drop in for long trips, or the pump itself needing calibration of its vapor kick-off/a new skirt, or insisting that the pump go to a particular number/even result in $ or gallons, etc...past the proper vapor kick off point...and so forth.


Does the above make sense?
 
#3 ·
Yes that all makes sense...but I never over fill my tank..I'm lucky to ever fill it to the top in the first place. Most of the time my truck has half a tank or less!
Its def something going on in the #2 port. It is not cleaning the gas vapors at all!
 
#4 · (Edited)
Yes that all makes sense...but I never over fill my tank..I'm lucky to ever fill it to the top in the first place. Most of the time my truck has half a tank or less!
Its def something going on in the #2 port. It is not cleaning the gas vapors at all!
When you smell it like that, and its slow to fill, the can is typically saturated.

There may be a kink or clog then that's responsible for the fuel backing up...so, start at the fuel door where the vent terminates, and look at the tube coming into it from below, and follow it back to the can, and, from the canister back to the tank.

You may see a kink/pinched spot, etc.

If you don't see a place where the line is funky, remove the line, and blow it out to see if there was something IN it.

Do not suck it out, that's icky. You can weigh them to see if over 4 lb too, but, as you say it works when warmer, it might be a temporary condition, etc. You can bake them out in an oven (That you don't cook food in anymore), etc, too.

:D
 
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