any guess on vin #s or is build date accurate enough? i have a build date of 10/03. never had an issue. i have had a rare knock now and then. but it was spark knock before i think it was the T flash..

it does explain a lot! now get to work on 2010 mazdaspeed3 fun facts!!!

thanks for all the hard work.. (you to jeff!)

beers

 

Kinda weird it took this long(end of 09) for this to surface.
Here's a link to the short thread where we were discussing it and it came to light thanks to a new owner and Ash8.

https://www.rx8club.com/rx-8-discussion-3/please-help-potential-new-owner-question-miac-181950/

Wondering about potential heater issues down the road as well.

Seems as if at least two 09's have now had this done in the last month or so..........and MIAC went away.

 

Well, I took mine out to increase water flow through my heater core.
I frequently turn on the heater to help out the cooling system on the track and I didn't want to reduce the flow.
It is also worthwhile to note that I do NOT have any sort of "marbles in a can" or heater core noises.

 

Seems like it's kinda car specific anyway.
Some are cured by simple octane changes and some aren't.
Some have always had it.......(including 09's) and some have not.
I don't track mine(yet), but I do beat on it pretty good and have never heard/had it.
Might be interesting if we could find a car that actually has MIAC and has the orifice in there???????

 

This is the "Application Description" Info direct from the AUST/UK EPC for the "Orifice"..

- 041201
FE10** -103028
SE17** -129710

The DASH - before the build date and VIN # means Used Up To, if the dash was After the Numbers it would mean USED From.

IF there is NO Application Description then there is NO change in this part and has been used since day ONE of Production and Year.

So Scott, if your car is a 10/2003 then you have this orifice installed, definitely.

IMO there is more than one MIAC type noise, this (it appears?), High Carbon build up, Old or fowled Spark Plugs ,Coils and or Leads, Gas/Fuel, extra HOT Throttle Body = Air Intake.

 

This is the USED FROM..." Application Description" which applies to the ''Hose SET'' Part Number, NOT including the Orifice.

041201 -
FE10**103028-
SE17**129710-

The Parts Screen shot here is the 'Orifice' Used Up to ( I still can't believe I overlooked this..I should be shot!)

 

i took this out when i installed my secondary radiator--Charlie at Mazcare told me then it was only there to decrease the sounds in the heater core.
I dont have any marbles in can noises--never have--before or after.
OD

 

Yes, I think Mazcare are correct OD, IMO that is all it can do, reduce the Coolant flow (Rush) into the Heater Core (radiator)...

As Jeff said, many are getting confused with "other" similar sounds that are not related.

But I still wonder why Mazda removed it ( the exact same part was installed in 1992 (ONLY) FD RX-7's BTW, then not in 93,94,96 series RX-7's).

SEE 1992 RX-7 Heater Parts Pic...

 

I got my coolant restrictor orifice today p/n F100-61-E09. here is what it looks like. It is 17.5mm OD, 7mm ID and 10mm long.

 

Thanks for the Pic...

What I find "perplexing" is why did Mazda installs this 'orifice restrictor' in every rotary first series production start in the FD RX-7 and RX-8, then stops using it after about a year of production in both model cases?..

RX-8 (FE) Installed Up To 1 st December 2004, never re-introduced.
RX-7 (FD) Installed Up To August, 1993, never re-introduced.

Then to re-install this device once an owner complains.

How does it effect the performance of the cars Heater?

 

^...................good question Ash. Glad I don't have MIAC or any symptoms thereof.

 

Time to drag this topic back up once again:

I noticed mine suffering this at 7500-9000. It sounds like the video, although I would say my first impression was more of paper fluttering against the wind. I took out my AP to measure the coolant temps while recreating the sound, and saw no change in temps.

So if anyone can answer my questions:
1) Does cavitation create lack of cooling? I'm pretty sure the answer to this is yes, but it'd be nice to hear people say so.
2) How quick will the temperatures rise if cavitation occurs? How long does the cavitation have to occur for the temperature to rise?
3) How does the engine read the water temp? Is it a continuous reading, or after set periods of time?

MM (if you are still reading this thread), how can one differentiate the sound between the aux port rattling, and cavitation?

 

I believe I can answer #3, but nothing else......sorry.
I'm reading water temp right off the ODBII port and mine is continuous.
It reads it right off the ECT sensor which I believe is on the block.

 

After living with MIAC for nearly 3 years I finally thought the coolant restrictor orifice part F100-61-E09 looked like a fix that has not been refuted. So off I went and got the dealer to order and fit part F100-61-E09. After getting confirmation from their tech line, they did this (just within the warrantee).

My MIAC noise is transformed, but the results are not all I'd hoped for:

Before: a "hard to be sure just what it is" noise at 7500+ rpm that resembled sand being thrown at the back of the glove box. I could have believed it was many things.

After: quite obviously liquid whooshing about noises at a lower 5500+ rpm, actually tailing off by 7000+ rpm. The sand against glove box noise has gone.

The original noise was worrying as it was hard to be sure what it was. The new noise is more obtrusive, not least because it occurs at "every day" revs. If I end up having to choose between one of these two noises I'll be going back to without the orifice (now I'm really convinced my noise was coolant flow).


'07 Sport

 

^..............Well, I guess it was a good datapoint if nothing else.
Guess I might give it some time before yanking it out.
Least it didn't cost an ungodly sum of money to try it.

 

Its funny - after years of hearing about this phenomenon, my car developed it on the current motor.

Its a definite, clinky "gurgling" that occurs immediately after lifting the throttle on a high-RPM excursion.

I think I'll just live with it since its more amusing than annoying and its a pretty meaningless noise, anyway.

 

i sold my rx8 because of this, i know it sounds crazy but it sounded like crap. now i have no 8 anymore, i was really looking forward at the toyota ft-86 when it comes out but toyota really went down hill with recalls

 

You have the REmedy water pump mod on this engine, I imagine?

 

I have an 09/03 build and just had the sound develop at 85K. I believe mine is the APV sleeves rattling. After going through my struugles of broken APV sleeves connecting mounts on my new engine build, I fear that I may actually break one if it keeps rattling like it is doing now.

Maybe a bridgeported 4-port turbo would be the cure

 

cant believe people still talking about this
its just the air in the heater core that gets pushed around

 

What was the consensus on MIAC at low rpms? Mine occurs between 2-3k then goes away, only under light acceleration/load, and sounds exactly like the sound from the YouTube video except seems to be coming more from the engine bay than the glove box. I know that the alternative explanations for this sound other than the heater core fix are detonation or bad cat, but if anyone could give me more details specifically about low RPM MIAC, I'd appreciate it.

'07 MT with 42k miles, stock, plugs and coils never replaced (BHR kit ordered and awaiting), no loss of power or hesitation that I can appreciate, always 93 octane.

Thanks in advance...

 

your issue sounds to be more similar to mine... mine rattles right around 3500 rpm, and only under light throttle... i already ordered the oriface piece and installed it into the hose, and it didn't change a thing...

as we speak, it is sitting at the shop, having it's plugs and coils replaced... they are also going to check out my cat, and check it's condition as well... i have 45k miles, stock, and plugs and coils were never replaced... i have no noticeable loss in power or any hesitation, and always 93 octane as well... but, the sound is driving me totally insane...

i'll be leaving work here in about an hour and a half... and will be putting about 100 miles of driving into it tonight, so i should have a good idea on if it helped at all...

will post an update when i get home...

 

Thanks K.... looking forward to hearing what your results are.

 

so... plugs, coils, and wires replaced... ecu reflashed, and retuned...

verdict is, noise is still there around 3500ish RPMs...



speaking with the rotary tech at the shop... he let me know what the issue is, though...

the noise is coming from the intake manifold control shutter valve... when it opens it is chattering...

i got some pricing on fixing the issue...

$115 to try running some sort of cleaner through it, which is supposedly from a mazda service bulletin... that includes labor and tax, but he stated that they would have to keep the car overnight, as it has to soak in for a while...

$650-$700 to replace the valve entirely... which he said is mostly labor, as it is a nightmare to get to...



on the plus side, after the reflash, plugs, coils, and wires... i have boatloads more power from the engine... and, maybe i'm crazy, or i've just been playing music more-so lately... but the chattering of the shutter valve is far less pronounced...

 

Thanks K, very informative post. Anyone else do this IM control shutter valve cleaning or replacement?