guy321

If I drive for a while, and make it rattle under accelleration, I noticed that it also rattles for a short time when I stop. my rattle definately comes from the exhaust pipe and i used a stethescope to listen to it.. it may be coming from the cat and i've made an appointment to have the dealer check it out on Friday. I've started a melty cat thread if anyone is interested.. i'll put updates there if that's the problem.!!!!

joyridevr6

I had a similar problem. I went to my local dealership and narrowed the noise down to the exhaust system.It helps if you have someone in the car to rev the motor while you listen from outside otherwise it is hard to hear. Anyway, it turned out that the insides of the catylitic converter had broken up and the noise was the pieces rattling in the exhaust. I had thought as many of you that it was a trans or engine problem but if you listen from the outsid it is definitely in the exhaust.

guy321

That sucks because I have an aftermarket exhaust, so even if it is the cat, and they replace it, I'll still have a rattle!?

RenKat

I think it's the exhaust heat shields.
I have had the noise from day 1.
I spent a day under the car trying to find the noise and found that the heat shield design has spot welded mesh points to keep the shields from buzzing where the top and bottoms meet.
I took the bottom header heat shield off and bent the top heat shield a little to make it tighter.
It made the noise a lot less for about an hour.
Then the top shield opened up from the heat and the noise was back.
Also I noticed that the stainless mesh pieces are shaped like a (T) and are only spot welded in the middle, there is a possibility that the 3 end points are flapping and buzzing on the heat shield inside.

When I get a chance I will make another attempt.

guy321

After checking out my exhaust system when cold, then again when hot.. I conclude that my problem may also be the heat shield..

When cold there's about 1/4 inch gap between the left rear corner of the muffler and the heat shield..

when it's hot it touches..

as it cools , the muffler and shield loosen from each other again and rattle.. that's why I get rattle on idle AFTER I drive the car hot..

while they are thouching, the acceleration causes it to rattle also..

Any ideas on how to fix this? Will some dynomat extreme on the heat shield help?

guy321

Yup, my problem is definately the heatshield. The muffler is being sucked up into the heatshield.. Those rubber grommets shrink up tighter than ********* in an ice factory.

I was thinking of drilling a hole in the heat shield and attatching a wire to it, then to the ground strap bolt, to hold the shield back a little further.. anyone have a better idea?

Oh yeah, this was evident only when the vehicle was hot.. I burnt the crap out of my arm, have nice little blisters to show for it.. so be caureful if you're checking!

gixxer

My noise seems to have gone away. I wonder if this high tech computer shut it up? Can't explain it. It was there when I installed the K&N and a few hundred miles later it is gone.

Farsyde

Man this is disappointing. Why? Because my Protege has the same problem. I really, really thought they would have worked out this issue since it's been 4 years, not to mention the advantage of not having pistons. The dealer (who btw are idiots in Tallahassee) apparently have cotton in their ears and think I'm crazy. They tightened the heat shield, raised the hood bumpers, and sent me on my way. It made the damn noise from then till now for all 5 years on the car. Turns out this is a known issue in the Protege by good dealerships (like south Florida). It IS detination and the remedy is throw in higher octane gas. The prob is I'm now paying 2.05 for regular (what it was designed for). You guys are gonna have to get an octane booster or go buy some xylene (or toulene if you can find it).

Because it wasn't mechanically detrimental they basically told me I had to live with it so I'm pretty sure you guys may be stuck with it unless the next PCM flash advances ther timing. I'm sure if you can get your hands on lower compression rotors that might help

izzo

I also have this darn problem. I have taken the car to the dealership and at first 2 mechanics agreed with me that there was an unusual noise but when i picked it up they claimed that there was nothing wrong. The noise was still there but suddenly none of them could hear it. About 2 weeks later my cat melted and they kept it for 3 days and got a replacement , i was hoping this would fix the problem but it is still there and it is sooo anoying.
I am glad to see i am not the only one experiencing this and sincerly hope we find a solution soon. Mine is also a AT model.

I actually came to this board in hope of finding a solution so at least i am on the right track and now know for a fact i am not imagining things.

ArvinC

Assuming the "noise" is NOT the cat melting/malfunctioning, is there anything to really be worried about? Or are we chalking this up in the "Mazda says this noise is normal for the RX-8" comlumn?

FWIW, my "noise" happens during hard acceleration at around 6000+ rpms. I'm going to assume it's not my cat, since I have not noticed any degredation in performance thus far.

Thanks for the info...

Arvin

Farsyde

for me this is a deal breaker. I've been obsessing over this car for 4 long years. Unfortunately, I've had my protege for 5 years with the damn rattle. I can't beleive that mazda would let this neon like issue into a $30K car. It is just so friggin annoying. My sanity isn't worth any car, and while I love my protege, you can be sure that ANY car I test drive or hear this sound in, I will never own.

Arvinc; My cat has no leaks, pieces, or malfunctions. There are no rattles from the exhaust or any part of it down the system. There is also no change in exhaust fumes smell. For me the beebee's in a can come on around 3500rpm's (out of 6500 redline).

Izzo; You're not imagining things. If you go to protegeclub.com you'll notice this has been a long and annoying problem for the protege. I really should check out the miata boards too to see if they are getting this same problem. Once again, the only fix mazda is willing to give us is a tank of premium to "flush out" the system, since the only other options is a new engine/lowering compression/or some other randomly stupid idea. This is the only upsetting thing I have ever encountered about mazda.

PS. Mazda of Tallahassee-you suck. If I tell you there is a damn noise coming from the engine under a forward load, stop telling me it's the hood bumpers before I shove em up your...... I'm getting all my service done on my own or in South Florida from now on.

JimW

I noticed this recently. It has a slight ticking sound with air. I thought it was my injectors but the sound was from underneath the car near the cat. Either the cat is plugged up forcing exhaust out of the flange or the flange just needs to be tightend.

RolenImportsRX8

My cars been in the shop for 5 days now for the same issue. I get this noise frome 5-7k, and sometimes higher. First they told me that it was the throttle body....nope...now they are ordering a part. I'm sick of the problems this car is giving me.

flyboyindy

Funny how we all have the same problem, (hard acceleration, between 4k and 7k... mine is automatic) And Mazda service gives everyone a different answer... maybe THEY should start reading these boards... Again... F for service for Mazda. =( I love my car...i love my car ...i love my car...

JimW

The only time I notice this is when the car is parked next to a curb or in the garage. i don't notice anything in the mid to high rpms.

izzo

well my car is on its way back to the workshop tomorrow. I have already had the cat replaced once but when I went to take it out on saturday i noticed it sounded unhealthy and was blowing a bit of smoke and the exaust smelt funny which from what i have been told is a sign the cat is gone ( again).
I too love me car but I am growing sick and tired of these problems.
i admit i drive my car reasonably hard but it is after all a rotory and is designed to be given a bit of stick but the problems I am experiencing can only be design faults. Mazda needs to get with the program or there will be alot on the market for sale second hand. The dealership is no help really with all of this , first they admit they can hear it then suddenly the foreman says there is no noise and the others who admitted to hearing it were nowhere to be seen, then the cat fails a week or so later which was replaced and now 2 weeks after that and about 500km it looks like it has died again.
I have owned my honda civic for going on 5 yrs now and its never missed a beat and this rx has been with me for 3 months now and i have had problems for 2 of those months. shame mazda shame.

and Eurocar mazda artamon is not much better.

I think they should get the mechanics to sign up here and get a clue as you guys seem to know more about the car then they do.

I am going to try and stick this out and get it running as it should or i will look into other options including bad publicity, selling it and or legal action, I did not pay 60+k for a car to have it sitting in the drive way sick or at the work shop.

It does not sound like it used to when i first got it and that is a good indicator that something is amiss.

why wont they just admit there is a problem and they are not sure what it is and what is causing it so it can be escalated to mazda australia/japan and get it fixed up once and for all instead of wasting my time and your time, time is something i simply do not have to waste.

<end rant>

thew

ITS PING !!! thats waht the Pinging sounds like in the Wankel..

make sure your running good gas. and try not to bog it down in low rpms with to much throttle.. Also get a tune up..

thew

my 84 rx7 did this to. That car was imported to CA with 3 Cats !!

the first one dumped into the 2nd one and they both failed.
so we just removed the cat's guts and replaced the 3rd one with a new factory oem unit. that fixed all my trouble..

The Cats Faild due to bad gas ! .. the Cats have to get hot to work right.. so bad gas and short runs with the car will shorten your cat life. Keep in mind I dont think they have Cats on the cars in japan.. Make your Dealer replace the whole exhust system !

izzo

I always run either SHell Optimax or BP Ultimate, i have sort of been testing both to see which gives me better perfromance and value. They are suposed to be the two best fuels available here
96/98 rated. If the stations i use are mixing their fuel to make extra money it is possible that it is bad fuel and with the way fuel prices are now these days it would not suprise me but they cant all be doing it...can they?

I will drive the civic in future for short runs and demand they replace the whole exaust this time, its really getting on my nerves.

thew

I worked at a Chevron Gas station a while back..

The owner would buy cheaper fuel mixes from Co's other than Chevron to suppliment the more Expensive Chevron Gas.

I think Chevron is ok with this as long as he buys 75% of his fuel from them..

So yes it is possible.. Esp with your gas prices..
Mazda Makes a hoter spark plug for the 8 buy them as well.. replace you air filter with a Green, and upgrade your Grounding wires and your Plug wires. These things will all help..

Tony Orlando

After a lot of experimenting with various throttle input/gear/load combinations, I'm beginning to suspect the noise to be pre-ignition (spark knock). Either that or the sound of the S-DAIS operating, perhaps even lack of oiling in the high RPMs? Either way, the sound has too much metal in it for my liking, and I plan on both driving a new car at my dealer to listen for the sound.

I may even experiment with devising a temporary intake cooler to see if it goes away. (An ice pack or something)

I'd like for those experiencing this to chime in on the following:

-Have you installed any screen or mesh on the front of the car?
-What are the temperatures where you live?
-What fuel are you using?

Perhaps if we can find some common thread among us, it'll help track down the cause.

Of course, it may just be a normal noise......

zoom44

from the description given in the other thread that you directed here Tony and things on this thread i tend to agree with you-it's pre-ignition/knock

Jobu-RX8

Ugh.

So I started the different thread on this, and I obviously have the same problems. I only use 91 octance (highest we get in CA).

What's odd is my car had some very obvious knocking and pinging from ignition problems, but that all went away with the new ECU flash. I originally thought the hesitation was related to that (my car hesitates a lot more often than it rattles/vibrates/rasps/clanks under WOT). But the new ECU didn't fix it.

izzo

I live in sydney australia, temps here atm are around 18-26 degree's C
I only use SHell Optimax or BP Ultimate which are rated at 96 and 98 respectivly
No i have not added any mesh to the front of the car, infact I have not modded the car in any way what so ever.

thew

it is ping.. it sound a little diffrant than your Piston Ping. but if you hear it esp when in to high of a gear while trying to ive it some gas ? thats ping. You can make any car ping.. but with the 8 it will most defanitl ping if you bog it donw too much. ie.. 4th gear at 5mph ......

Anyway. if your running 91 oct or better and your pinging all the time not just when your in the wrong gear,, then get that car to the dealer right away.