The two tiny holes on the center iron, just above the ports. They lead into the injector openings. My S3 13B engine has them:



but my S4 DOES NOT. I traced them into the throttle body's bypass holes and if they are what I think they are, it might explain why my car is starving for air at idle. However I'd like someone who knows to tell me and also why S4 does not have them.

Much appreciated.

 

Primary injector air bleeds. S4s do have them; I'm looking at a picture of my bare S4 TII block right now, and they're the same as in your picture. They have zip to do with idle, and are just there to improve fuel atomization.

 

Are there any fuel injected irons that come without these?

They're pretty much unrestricted air paths into the engine, at least with the S3 intake system, and the engine would suck that air in when running. ECU is probably designed to take them into consideration and provides enough fuel to match that extra air. By the size of the holes, there's probably enough air coming in to make a difference of a few hundred RPM. So if they're blocked, there's not enough air and too much fuel.

I mean, at idle, what other paths does the air have into the engine besides the ACV?

 

your title sounds like the title of an old sex ed video

 

They should all have them. S4s & S5s both have primary air bleeds, and S5s also have secondary air bleeds. S3 GSL-SE 13b irons would be very similar to S4 irons as you picture shows.

They'll connect to a nipple on the inner side of the LIM, which will have a line running up to the TB. The source needs to be metered air (before TB butterflies), so if yours is not connected to anything now, make sure you don't connect it to a vacuum source. A vacuum source could pull fuel up to the TB.

That being said, I don't think they're going to make significant changes to airflow into the engine. Take a look here at the bleed insert peices: http://www.mazdatrix.com/c-6.htm. They have tiny pin holes for the air to flow through, which are much smaller than the holes in the iron.

If you're having idle problems, things to consider are vacuum leaks, BAC, air bypass screw, variable resistor and even the water temp sensor on the back of the water pump. All of these will affect mixture/airflow at idle.

 

Wow, mazda trix wants $909 USD for an S4 NA AFM, talk about steep.

 

are these freakin diffusers and bleeds even necessary?

They still spit fire regardless from running super rich. More air, less fuel. Problem solved, right?

Devcon/jb weld those things shut if you dont want them. That's a cold enough part of the engine you could probably get away with rtv black.

 

 

Yes, an educational film for the youth. Possibly even a spoof by Harry Enfield.

 

Yeah, I looked around for different intermediate plates and seems they all have those. So I figured I must be having a brain fart, so I went and pulled the LIM off and yeah, I have them. I was sure there was something I didn't have there, and it's the square ports for the ACV - those I don't have, so I got confused.

I thought I didn't have the diffuser air bleed holes because I couldn't blow air through the tube that goes to them. Upon closer inspection they have some kind of restrictors inside, that my S3 13B does not, so with the S3 engine I can blow through the holes no problem... Well I "cleaned" them and now I can kind of blow air through the S4 ones as well. I don't know if that's a good thing, but whatever. Took the time to inspect the injectors as well while I'm down there.

Yeah, I know about all the other stuff, thermo sensors, TSP, AFM, etc... I just thought maybe there was something else I missed, and these holes came to mind.

Thanks for the info. I'll stop worrying about them now and will continue with my quest for idle.

 

From the GSL-SE service highlights:

 

Sweet.

What book is that from and where can I get it? Seems it explains all the systems in detail... All I have is the FSM and it's useless.

 

pm me your email address, i'll send it.

 

hahahahahahahahahahaha!!!! Lmao!!!

 

i think that made my dayhahahahahha