Here's a follow-up to my September 30, 2013 post above:

Having had the MIAC/sand through the glovebox addressed under warranty by the local Mazda dealership late in the year - just a month prior to putting my car away for the winter, I was pleased that this annoyance had been licked. Very pleased, I shared my success here.

I was surprised the following year to discover that my success was short-lived, with the MIAC sound returning (and becoming regular at 5-6+K rpm) a few weeks after bringing the car out of storage. It was super frustrating having not only to tolerate the noise again, but having to explain it to instructors and passengers whenever track lapping or just driving my RX-8 like it's supposed to be driven.

Never one to rush into things, a couple of weeks ago I ordered a new orifice - so it is still available, at least in Canada - as I was starting to doubt whether the original had even been installed in the first place. Today, since I was doing a flush and installing a new coolant tank to rid myself of the intermittent post-high rpm "Low Coolant" warning light it had also developed, I went at it.

If you're doing the orifice job, you'll find it much easier to do with the battery box removed (the two semi-hidden battery box bolts are a joy, BTW). I actually have no idea if you could do the orifice without removing it - changing the coolant tank required having it out anyway, so...

When I removed the correct hose and found no orifice, I was not entirely surprised. Still, I like to give my fellow tech the benefit of the doubt that he/she didn't just bill for it and throw the brass orifice in the scrap metal. I found it, ground down to fit, in the heater hose at the firewall, where it would have been easiest to access.

I removed the old one with a drill bit, and put the new one where the parts diagram found earlier in this thread showed it. Too soon to be certain, but several 8+K rpm WOT runs on the way home, including one after several minutes on the highway, and no MIAC. Fingers crossed...



Lazy but inventive Mazda tech ground it down to fit where it wasn't meant to fit...
This hose, right beside the water pump on the thermostat housing, is where the orifice is supposed to go. Hmm, no orifice here. Yet.

 

Can vaccum leak cause miac throughout rpm range from cold to warm, stalling when warm and hard start when warm? Also a hunting idle when up to full warm temp?

 

I have a 2007 with only 82k miles on it. The other day I started it up and went to work. I was running a little late so I didn't get to warm it up. I drove 7 miles then stopped at a stop light and all the sudden the car died and would not start back up and has not started since. The car didn't make any noises when it died it seemed like it just stalled out. Now it will turn over but will not start. Any ideas on what this could be. I did have an evap sensor light on and after the even now I have these codes up P2259, P0661 P0037 P0031 P0443. Any help would be appreciated.

 

The codes aren't necessarily the problem. To start and run it has to have fuel and spark, so these would be good places to start. It might even be as simple as a blown fuse. Start with the basics first.

 

Hey guys I contacted my dealership about this sound and presented the solution and part number. They looked into it and told me that the fix for this was removed from the bulletin in 2012 so is no longer free repair from mazda and was going to cost me 360-370$.

So I'm getting ready to tackle it myself. Just wondering if anyone has a couple pointers on doing it. I know I need to pull the battery to access it and I have that channel locks to pull the hose. I read some one mentioned plugging the nipple on the heater core as soon as you pull the hose to limit the coolant spill. Any suggestions on what to use that fits well? Should I just drain the coolant and what about this "burping" the coolant system? I want to get a thorough idea of how to do this start to finish so I don't get stuck half way with a car I can't move since this is my daily and only have one day to do this.

 

Just drain it all if you're worried about spilling it, otherwise just spill whatever and then top it off.

"Burping" it literally filling it up and letting it idle with the radiator cap off. The idea is to allow any trapped air to escape. It won't overheat at idle with the cap off as long as the cooling system is working correctly (water pump, fans, thermostat, etc)

 

Just got the miac sound but mine sounds more like some pop corn maybe seem odd hope it just goes away kinda annoying I was told it's normal that these rotarys make all kinds of noises

 

"hope it just goes away" and "rotary" don't go together.
You were told wrong.
Fix your car.

 

I don't know any cars that can just magically fix itself. Wishful thinking is bad.

Rotaries don't make MIAC noise normally.