Did air filter replacement yesterday and ran across a plastic tube that hooks up to and under the air intake accordion. Cannot seem to find this part name anywhere on Nissan'S diagrams? It goes back under the throttle body, under the intake plenum and just sucks in unfiltered air? Am I missing something? Felt around back there for like an hour. Don't see anything that would hookup on the other end of that tube. Is this unmetered air?
Does anyone know the part name?

 

I think what you are describing is the 'sound generator'. Check out this thread for more info: Plastic Tube Left Over From OEM Intake

 

Hi wildcat.
Thanks for reply.
This is indeed the 'tube' I found.
Funny about that thread, people can't really tell if the air gets sucked in or blown out of this tube.
I may try a filter of sorts and leave it on instead of capping it off.
Just totally weird as it seems to allow for unmetered air (to enter Or exit) it's unmetered by MAF. So how is air mix calculated accurately?
Idungetit.

Thanks again for the share.

 

I want to take a look at one now. There is no way that part could be after the MAF sensor letting that much air in. Most cars use the MAF, TPS, MAP, ECT, O2, to control mixture.

 

That's what threw me for a conceptual loop.
It is open. Might be 'static' air there due to relationship with the air flow from the air box?
I'm idling fine. But this puts questions as to what really happens if it is blocked off? What if main intake gets partially blocked? Does it now draw air from the resonator? What if air is pushed through and out the resonator? Does that mean the ecu and MAF accounts for the air loss in some way so if you block it off you mess up your fuel/air? Sooo many Q's.

 

The tube is closed, as in it's not pulling outside air in after the filter. I removed mine a few years ago and capped it off. It doesn't effect how the car runs one way or the other.

 

Someone on a other forum mentioned that there is a diafragm in the middle like a Passive reflex in a home speaker..

 

We finally got one in the shop yesterday and I took a look while checking the air filter. It does have a hole in the intake tube where it attaches but there has to be something blocking off the air like other people mentioned. I wanted to take it apart and look in there but that's not a good move on a customer's car!