Mr.Mango

iTrader: (2)

Hey guys,

Did some searching but couldnt find anything directly related to my issue. This is in relation to Mazda's "MTOL -04/56 : WHINE/SQUEAL FROM ENGINE AT IDLE"

I installed a AEM intake 2 week ago and since this past saturday afternoon I have been getting the EXTREMELY high pitched whining noise from my intake system. I have owned the car since new (04) and have never noticed it previously... To give you an idea of just how loud it is, I can sit in my house with the windows closed and can hear the car on the street.

Obviously this is a known noise and not a issue from Mazda's pov. However it is quiet annoying and I am wondering if anyone has "rigged" something up to quiet her down or have a possible fix for this?

Here is what Mazda says (I confirmed this is my noise)

"Some customers may complain of a high-pitched whine or squeal noise from the engine at idle. The noise can be eliminate by raising the engine RPM slightly above idle. This is most likely caused by the primary port jet air nozzles and/or the metering oil pump air ports. The jet nozzles are located in the primary port of each rotor. The jet air flow is achieved by using air flow from an area prior to the throttle plate. The metering oil injection nozzles also use this airflow prior to the throttle plate to assist oil flow into the engine.

• · This creates a metered vacuum into the engine and may cause a high-pitched whine at idle. This noise is considered to be a normal characteristic of the RENESIS rotary engine. Use the following procedure to confirm noise is from the jet or metering oil pump nozzles.
• · Remove engine cover.
• · Start engine.
• · Locate both air supply hoses for jet air nozzles and metering oil pump nozzles. Hoses are attached to the air duct located between the MAF and the throttle body. Disregard hose that attaches to the oil filler tube.
• · Confirm noise is caused by jet air or metering oil pump nozzles by temporarily pinching off air supply hoses using pliers.
• · No repairs should be attempted if noise is reduced or eliminated."

nycgps

iTrader: (1)

Make sure u dont have a leak anywhere.

GK1707

iTrader: (10)

Check the VFAD nipple under the UIM. If you install an aftermarket intake you need to cap the nipple or you'll have a vacuum leak.

WreakLoosE

^++++++1

9krpmrx8

iTrader: (46)

That whine is normal with the AEM. But not so much you can hear it inside the house so I'm not sure what is up with that. Probably just normal though.

Mr.Mango

iTrader: (2)

Thanks for the responses guys, did some digging after work.

- Nipple for VFAD was 100% capped.
- Line is 100% for the OMP not the air jets
- Inspected intake piping between MAF & TB no obstructions
- Smoke tested the intake manifold from the nipple where the Vfad goes (TB was capped obviously) No leaks found
- Smoke tested the line causing the noise, no leak between it and the OMP Nozzle junction.
- Scanned for codes with IDS, none present or pending.
- Using the IDS I manually controlled the OMP, the sound is still there when turning it off (dont worry I premix)

As you said 9k its normal but its sooo annoying haha I ordered new nozzles, lines, & vacuum hose for the OMP just to be safe... So I will drop the motor saturday replace those and report back with my findings, gives me a good chance to Zoom the SVV & intake manifold while I am at it.

If anyone has a fix or ideas let me know

Mr.Mango

iTrader: (2)

So update, pulled the motor saturday replaced the OMP Nozzles & Lines, along with the vacuum line, reinstalled and.... the noise is still the same. I might go back to OEM and see if the noise stops, or maybe buy a RB Revi.

ShellDude

iTrader: (12)

did you ever pull your UIM or check behind it near the oil filter? There's an air line back there (I can't remember which one) with a green/white bulb that when disconnected will make a very annoying high pitched noise at idle.

I accidentally popped mine while installing a relocation kit. the high pitched whine was unmistakable, as was a rough idle.

Since you smoke tested it and have access to an IDS I doubt this is your problem, but if you're bored one day pop the line and you'll likely recognize the noise.

Mr.Mango

iTrader: (2)

Intake was off on the weekend, replaced all vacuum lines & checked the check valves, everything is 100% connected & working. Smoke tested it again once back together with no leaks found.

The whine I have is 100% coming from my OMP line (the one I am hearing anyway)

Its odd as I have never heard it this loud on any 8 before, that includes MS & AEM intake vehicles. Been working for Mazda well before the 8 came out and never had a customer complain of it either.

abesRX8

Mine is very loud as well, has been that way for years, I take it as a good sign personally because to me it says the OMP is working properly ( maybe not) but gives me hope. Mine is as loud as yours that it is so high pitched that I could hear it in the house while the car sits outside warming up.

sweatr

Thanks man, I have wondered about my whine also. I will try the test this weekend.

Mr.Mango

iTrader: (2)

Good to hear I am not the only one! I have been a owner and worked on alot of RX8s over the past 10 years and never had heard it prior to installing the intake.

Its annoying but I have quit worrying about it after replacing the lines, testing the pump and doing the testing I have done.

AndrewM

Check out this older thread where the issue is discussed.

I also just had this exact issue on my 8, which has MS CAI. I got my engine rebuilt at the dealership, got the car back and wondered what the crazy-loud whistling noise was. Turns out it's because they cleaned out the tube where that air flows (I guess the one connected to OMP nozzle).

In the thread I linked above, a user posted a video which perfectly demonstrates which nozzle/tube causes the noise:
Anyway, it's basically a known issue and I found in some other threads that people would purposely obstruct the airflow so it doesn't whistle so loudly, but honestly I don't know whether or not that is a good idea. I have yet to find the definitive conclusion on this subject.

sweatr

Error on the side of caution and don't plug the line. My OMP is new and the whine is not as loud as you describe but I can hear it at a stop light some. I don't pay much attention to it now.

Danieljjvv

SOLVED my problem
It is the top vacuum pipe leading to the omp Injectors , it seems that the stock air box muzzles out the frequency of the pipe.
I took a small reusable fuel filter to muzzle the high pitch sound out(you can still hear it when you open the hood if you really listen)

Sketchy_RX8

I go to meets and people think I'm supercharged constantly have 400+ hp guys trying run me all the time lmao

motodenta

Its absolutely normal since you change intake design, hence, delete resonator which in front of it, and sound/ high pitch become more hearable.
There is an idiot on youtube with same problem, whom strip whole car front end for this lollll

General set up of Mazda is in the way to normalise whole character of rotary engine in way to show it equal to other engines.
Even if you change position of air feed elbow of oil injectors, it would give hard times to factory MAF reading in start up.

Pro tip if you want to eliminate this sound add one inline gas filter between elbow and pipe, as a silencer.

Sketchy_RX8

ROFLMAO I think I know who you're talking about I believe you're talking about DriveByMadness... I tried giving him the BOTD and tell myself that maybe he was just doing it for footage and maybe too make few people who made the same mistake feel better... But idk never having experienced it I found the source in literally about 30-40 seconds the first time I did hear it...

Anyway you're totally right about the filter I just let it be it's not hurting anything... Kinda goes back to that old saying "Don't try to fix what's not broken"

Just wanna say thanks to everyone in this thread tho and throughout the entire forum...when I first heard this noise kinda worried me and thankfully like usual RX8club was there to help... I'm new to the forum but I've been using the club for info for a couple years tho... I finally decided to take the plunge and sign up lol

TeamRX8

iTrader: (25)

Adding a restriction or filter defeats the purpose for the jet air device. The correct solution would be to increase the fitting and attachment hose end to a larger ID to slow the flow velocity down. Which is why it’s whistling in the first place. A lot of those crappy intakes weld the tube fitting on, then put a drill through to make the hole. The hole tends to be smaller than the tube id and has sharp/square edges, all the ingredients needed to make a whistle.

or in my case since it’s only purpose is to help economy and emissions at idle and low rpm was to instead grind it off on the intake port side, then tap and install a threaded plug on the other end to eliminate it entirely for a race engine.

.

motodenta

I did't want to give direct name however sometimes it SpokenByMadness ;d
I like that sound as it reminds turbine noise back in oil platform days.
Putting gad filter wont restrict flow as they have + 100l/h flow rates per-se, air injector feeds never would exceed it, whole engine on idle has 5~8 g/s flow.
I never examine one of these cold intake feed junctions they might have some deformity on welding areas.

motodenta

What you grind, barb fitting on intake or injector side ?
air for injectors is important to prevent oil atomisation.

TeamRX8

iTrader: (25)

as usual, you have no idea what you’re talking about.

.

motodenta

Congrats, you see now .

Sketchy_RX8

Ok so that brings me to my next question then... You said you plugged it for race fitted motor but would it be catastrophic to do this to a street driven 8 or totally acceptable... Don't really care about fuel economy but not trying to stress my motor beyond reason for nothing but to rid myself of a noise like I said just not worth it but if it can be justified by having some means of benefit than I may consider...

Also I personally don't have a crappy intake genuine AEM over here lol but the intake has nothing to do with the noise other than when the vac. hose is attached it amplifies it a bit... But, I have experienced cheap ebay intakes that are just awful especially on the 8

motodenta

101 And god create edit.

Well based on my observation from teamrx8 which normally lurking on my posts, he/she doesn't have any basic comprehension over mechanic fluid,
sadly this leads his/her to old and rusty judgments.
OEM position of oil injectors air feed would leads to pressure drop on some throttle body position why should someone bitching around "restriction" by adding
gas filter ? which doesn't make "restriction" in first place.

For understanding vacuum behaviour of these injectors all you need is, to utilise a quality gauge, not cheap gauges or oil filled gauges, and monitor them
under various conditions.