So, yesterday I was mounting some of the parts of my car's engine (Mazda RX-7 FC 13B NA, 1987) when I noticed this:



This is the bottom of the "tube" that goes from the MAF to the intake.
1-> Can anyone tell me what those "pipes" are for?
One of them is closed with a rubber cap but the other one is open, and that got me thinking:
2-> "Well, if that's open, then the air is going to enter throught there into to the intake... In that case, what's the air filter for?" and also:
3-> "Humm... If the air enters throught there, will the MAF be able to measure the air mass that goes into the intake correctly?" My guess: no!

Your help/information/opinion/point of view, much appreciated!

 

just plug it up aswell cause if you dont its considered a vacuum leak & your call will sputter a little

 

If only I had somewhere to connect it to... But there's nothing left to connect.

 

That picture is insanely dark. All I see is a silhouette.

From the shadow, I am guessing that it's the sub zero start squirter. Either just cap the nipple with a new vacuum cap, or remove it and install a blockoff plate. Mazda issued a TSB that the system is to be removed. Additionally, the sub zero reservoir is located on the firewall near the charcoal canister. Remove it as well.

 

Hello Aaron. Thank you for your answer.
I'm sorry for the picture being too dark, but althought it's dark, here on my computer and on the camera seems bright enough to understand. I think the computer screen you are using may need some setup.
I recommend you to visit this website:
http://www.quickgamma.de/indexen.html
and use their software (it's free) to correctly calibrate your computer screen so you can get the best of it.

Anyway, I've edited the picture to be brighter so you can see it better:


Did it help?
And yes, you may be right. It may be the sub zero start squirter, as you mentioned. I've searched the FSM, and on page 1-17 the diagram shows something marked with the letter 'A', but it doesn't have a description, so by looking to it one does understand that there is something in there, we just don't know what it is...
Since I bought the car and started working on it, I always wondered what was that white small tank on the firewall near that canister, with a green smelly liquid was for... Now, it's answered!
So, you are telling me that I can remove this and cap that pipe? Does the FSM talk about this system?
I'm asking that so I can see what are the parts that I need to remove

 

Haha, I'm sitting behind three monitors all perfectly calibrated as part of my day job is building websites and thus dealing with the graphics work associated.

I checked an old intake tube I had in the garage last night.

The big hole is for the BAC valve.

The little capped nipple is for the purge valve.

Now, being a Eurpoean FC I don't know if the purge nipple is used. You'd have to check the FSM for your car. The emissions system of the Euro FC is very similar to the GSL-SE, with some early SA mixed in.

 

Oh, I didn't know that. Then maybe it's all of the people here who have their computer screens too bright (including me). That's a computer screen setup I would like to have (3 monitors)


So that means my car's BAC valve is disconnected, right...?


Are you talking about this purge valve?



I forgot to mention, my car was imported from the USA, so I guess it's equal to the ones in the USA...
So in that case, it has to be used, right?

 

On my S4 NA engine, the smaller nipple was capped from the factory (like the one in the pic). My car also never had the recalled subzero start system, which is what my guess would be based on its location. The large one connected to the BAC, as mentioned.

 

Found out yesterday. The large one indeed connects to the BAC valve. The smaller one doesn't seem to be used anyway.

Thanks for the help, everybody

 

Wish I saw this post sooner, I could have told you what that was. sorry

 

No problem. Aaron Cake gave me an answer, and it was correct! Thanks anyway