Built in air filter in air filter box - rev drop issue

most everyone is just removing it. i have removed it from all 4 of my toyotas. i just take the MAF sensor out every 50k miles or so and clean it with MAF spray and put it back in. just to clarify, this is that white screen looking filter that is attached to the air filter cover so to be directly over the air filter?

rich_d said:

most everyone is just removing it. i have removed it from all 4 of my toyotas. i just take the MAF sensor out every 50k miles or so and clean it with MAF spray and put it back in. just to clarify, this is that white screen looking filter that is attached to the air filter cover so to be directly over the air filter?

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Yes it is. It is attached to the filter cover below the MAF. Do you just pry it out? It looks like it’s plastic welded to the air filter cover.


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Mercron said:

Yes it is. It is attached to the filter cover below the MAF. Do you just pry it out? It looks like it’s plastic welded to the air filter cover.


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yes.. just pry it out, it will break,, all of mine have. and i just throw them away. you can search on the forum and other discussion boards about the topic. i found one still in the 2008 matrix i bought last april and removed it. it was nasty dirty..
some people have been successful at not breaking it while removing it.

Received my "ARES" CAI via FEDEX today. Hope this cold air intake is any good. We shall see soon enough.
BTW is there anything to be gained by removing the filter cover below the MAF, specifically on my '16 Corolla S?

pewtavert01 said:

Received my "ARES" CAI via FEDEX today. Hope this cold air intake is any good. We shall see soon enough.
BTW is there anything to be gained by removing the filter cover below the MAF, specifically on my '16 Corolla S?

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people say it helps. my cars seem a bit peppier with it gone.

just some info from google search. but it is what you are asking about

rich_d said:

Removal of Charcoal Filter from Air Box

Ok, I've finally gave in to temptation and removed the "secondary filter" aka charcoal filter from the airbox of my Highlander. It was relatively easy. And yes I took pictures. I'm post the how-to shortly. The filter, contrary to what many say is quite restrictive. Also, I noticed an odd 3D...

www.toyotanation.com

DIY: Secondary Air Filter Removal

Okay, disclaimer first... I have no proof that this modification will not do harm to your engine. I have no proof that this modification gives any...

www.tacomaworld.com

just some info from google search. but it is what you are asking about

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Thank you. I wasn’t using the correct keyword for this filter when I Googled it and couldn’t find info on it.

It’s basically a charcoal filter to filter blowby gas exiting the air intake when engine has just shut down. I don’t really see the point of this since the throttle valve is closed already.

Anyway I’m gonna try to remove it this weekend. I hope it removes the rev dip I experience when pressing the gas from idle.

PS. I’ve got almost 160k miles on this filter and it’s really dirty. I don’t know why this isn’t a replacement part since it restricts airflow.


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Mercron said:

Thank you. I wasn’t using the correct keyword for this filter when I Googled it and couldn’t find info on it.

It’s basically a charcoal filter to filter blowby gas exiting the air intake when engine has just shut down. I don’t really see the point of this since the throttle valve is closed already.

Anyway I’m gonna try to remove it this weekend. I hope it removes the rev dip I experience when pressing the gas from idle.


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just make sure you aren't in a state that will check that each year.

your rev-dip may be related to gummed up stuff on your air intake valve. just needs carb cleaner to clean it up. i have had that happen a lot on cars because of just gunk build up over time.

rich_d said:

just make sure you aren't in a state that will check that each year.

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HI doesn’t require it.


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rich_d said:

your rev-dip may be related to gummed up stuff on your air intake valve. just needs carb cleaner to clean it up. i have had that happen a lot on cars because of just gunk build up over time.

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I don’t see an air intake valve my Corolla’s throttle body.

I already cleaned the original throttle body’s butterfly valve and no change. I then replaced the entire TB thinking the original was defective. No change as well.

I also replaced the electronic accelerator pedal and no change either.

PS. I’m not getting any codes or check engine lights either.


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Mercron said:

I don’t see an air intake valve my Corolla’s throttle body.

I already cleaned the original throttle body’s butterfly valve and no change. I then replaced the entire TB thinking the original was defective. No change as well.

I also replaced the electronic accelerator pedal and no change either.

PS. I’m not getting any codes or check engine lights either.


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The butterfly valve is what i was talking about but couldnt correct what i said till now but u got it. As long as it moves freely and doesnt stick in any way.

rich_d said:

The butterfly valve is what i was talking about but couldnt correct what i said till now but u got it. As long as it moves freely and doesnt stick in any way.

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Yes that one is clean since it’s a remanufactured TB I got in there.

I’m still getting a rev dip going from idle of 700 rpm to 1,200 rpm then back down to 700 rpm when I step on the accelerator 1/4 inch and maintain it. I stall the car sometimes when I start de-clutching thinking I’m still at 1,200 rpm.

My guess is air is restricted by that charcoal filter and MAF is sending signal to the injectors for more gas then cuts it down when more air actually gets through. Or, my oxygen sensors need replacing, or I have a clogged fuel injector.


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Mercron said:

Yes that one is clean since it’s a remanufactured TB I got in there.

I’m still getting a rev dip going from idle of 700 rpm to 1,200 rpm then back down to 700 rpm when I step on the accelerator 1/4 inch and maintain it. I stall the car sometimes when I start de-clutching thinking I’m still at 1,200 rpm.

My guess is air is restricted by that charcoal filter and MAF is sending signal to the injectors for more gas then cuts it down when more air actually gets through. Or, my oxygen sensors need replacing, or I have a clogged fuel injector.


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Could be a throttle position sensor that is slightly off and needs calibration?

rich_d said:

Could be a throttle position sensor that is slightly off and needs calibration?

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Thanks but there TPS is built in to the throttle body and electronic accelerator that I just replaced.

Last resort is to bring to the dealer and have them diagnose it with their scan tool.


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Mercron said:

Thanks but there TPS is built in to the throttle body and electronic accelerator that I just replaced.

Last resort is to bring to the dealer and have them diagnose it with their scan tool.


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Im just giving suggestions. I havent messed with the tps on my 2016. If the filter removal doesnt work, we all can hopefully figure it out

rich_d said:

Im just giving suggestions. I havent messed with the tps on my 2016. If the filter removal doesnt work, we all can hopefully figure it out

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I appreciate it. I’ll post here how the charcoal filter removal goes this weekend.


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Mercron said:

I appreciate it. I’ll post here how the charcoal filter removal goes this weekend.


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Mercoron, another thought. on the 2004-2008 corolla, we had rev-dip issues with those cars or the two i had, and i found that replacing the intake manifold gasket totally fixed that one, but i haven't heard of that happening with the 2014 and newer corollas..

rich_d said:

Mercoron, another thought. on the 2004-2008 corolla, we had rev-dip issues with those cars or the two i had, and i found that replacing the intake manifold gasket totally fixed that one, but i haven't heard of that happening with the 2014 and newer corollas..

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Rich-d, yes I already replaced the intake manifold and throttle body gaskets when I replaced the PCV valve. Didn’t solve the issue.

Another thing I did was clean the MAF sensor with an MAF sensor cleaner and no luck as well.

Spark plugs were replaced a year ago too. Alternator was replaced 6 months ago.

Thanks.


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