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Discussion Starter #1
How come the Fj comes with 2 air filter. One is the one you replace and the other one is the white one that comes permanent glue to air box. That one one is super dirty on my Fj. Can it be clean?
 

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that is a filter designed to absorb un-burnt fuel that is in the intake system after you turn the car off and keep it from escaping into the air. The theory is that when you turn the car back on the inrush of air will purge the filter be burnt. I removed mine and the one on my wife’s 4runner. This wont effect your emissions testing because they only check exhaust. i saw an increase of .5 a mile per gallon. don't know about the wife's, she doesn't track her mileage.
 

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Discussion Starter #5
Thats what i was thinking, cause I see no point on having a clean K&n filter with a dirty white filter behind it. I took the box off and I look through it, and you can't barely see light through it.
 

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That filter shouldn't be dirty unless dirt is getting past your primary air filter. And while I've ran K&N filters on cars before, that tells me dirt is getting past the K&N to the second filter.

Wow, glad I don't run K&N filters now. Anyone else running K&N and have this issue?

P.S. (At my 30k mile maintenance, the secondary filter was white as snow; using a stock primary air filter).
 

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Im running K&N n mines appeared clean last i looked... Doesnt matter im going to remove it as so as i have time
 

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Im running K&N n mines appeared clean last i looked... Doesnt matter im going to remove it as so as i have time
Post up when you do. Mine is very dirty looking, almost black. But I am hesitant to start chopping stuff up while the vehicle is under warranty.
I found mud residue behind that filter on the airbox, MAF and throttle body.
I can only assume that if muddy water got that far, that this filter is probably trashed.
 

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It's a carbon charcoal adsorption filter and is designed to take care of fuel vapors. It can be cut out but is not designed to be easily replaced.

Should be no impact of OBD2 diagnosis. Maybe if you live in an area with yearly emissions testing they might say something about it. Or maybe not
 

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If your secondary carbon filter is dirty than I'd ditch whatever primary filter your using and get a better filtering one, now.

DEWFPO
 

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That too
 

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I took mine out. Very easy. Just cut a small hole in it and yanked up. Used a lighter to burn off the tiny nylon threads that remained welded to the lit. Wiped off any lose particles and reinstalled. Didn't notice any change but the idea of getting a aFe Pro Dry filter and having the welded in filter there seemed silly to me. Wort case, I but a cold air intake or new lid with the charcoal hydrocarbon filter in tacked before I need major service to avoid Toyota flicking me crap.

Pictures to follow.
 

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that is a filter designed to absorb un-burnt fuel that is in the intake system after you turn the car off and keep it from escaping into the air. The theory is that when you turn the car back on the inrush of air will purge the filter be burnt. I removed mine and the one on my wife’s 4runner. This wont effect your emissions testing because they only check exhaust. i saw an increase of .5 a mile per gallon. don't know about the wife's, she doesn't track her mileage.

WOW .5 mpg is pretty good for a simple mod
 

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Is this filter still there with the TD CAI? I have removed my intake, tube, and throttle body and didn't see a secondary filter anywhere.
 
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