Engine sounds like it is going to explode above 5000 RPM
 

I've been living with this problem for more than a year hoping that the engine would expire and I could get a new one under warranty. Unfortunately it is a tough beast and the problem apparently isn't sever enough to kill it. Here are the details..

The car:

- 2007 GT Automatic (don't hate, my wife doesn't drive standard so my hand was forced) with Mazdaspeed intake and exhaust
- Purchased used in 2008 with 10K km on the Odometer
- The engine ran great at the time I purchased it with the noise showing up about a year after purchase

How I use it:

- It's my daily driver. In the 3 years that I've owned it I have driven it nearly 60K km with the odometer currently just under 70K km.
- I live in Toronto, Canada so it sees all the seasons with plenty of time in the snow during the winter
- I have always driven it hard with a lot of my driving being done in manual mode with near redline shifts
- I have tracked it once and pushed the car extremely hard. I made the traction control freak out but my version of an italian tune up didn't fix the engine noise

How it's maintained:

- I've followed the service schedule since I purchased the car with all work happening at the dealer
- Oil changes have generally happened 3000-5000 km intervals
- The problem has been reported to the dealer a number of times but they tell me they can't find anything wrong

The problem:

- The car rev's well and sounds normal under 5000 RPM
- Whenever I push the engine past 5000 RPM the engine puts out a a sound like the engine has gone out of balance and components are banging against eachother. I've read about the marbles-in-a-can sound where engines are losing compression but this sounds worse. However the engine still puts out plenty of power even while making the noise.
- The car also has a rough idle where the RPMs dip down to the 600-700 range and the car shakes. This hasn't really bothered me too much but might have the same root cause.

Please let me know if there is any other info I can provide. I have access to a fully equipped shop so I can tear into the car based on your recommendations. Thanks in advance for any help you can give me.

J

The fact that your issue begins at 5000rpm leads me directly to the Marbles in a Can issue. Or possibly the SSV... At 5000rpm is exactly when it opens.

Does it sound kind of like this?:

@Vulcan,
Nice post, I wish more ppl would provide that much detail when requesting help.
AND holy crap it's in the right sub forum ... BRAVO BRAVO A++ Sir!
LoL I've seen such a bad trend lately :(

@Wingznuts
Nice video ... is that you sticking your hand in there!?!? Tight fit.

First:
Not to split hairs.. with Wingznut but the SSV does not open exactly at 5000 rpm, unless you have access to an area of the ECU most of us don't know about.
As far as using the Access Tuner Race we do not have any real control over when the SSV opens, IIRC from the MM webinar it's primarily a load based trigger.

Basically it's like this:
http://i274.photobucket.com/albums/j...Parameters.jpg

@Vulcan
Need some more info:
- @ 70k have you changed the coils yet? These are cheap to buy and easy to use HEI Ignition Tester --> http://www.fastenal.com/web/products...0245717&ucst=t
- Plugs?
- Clean the Maf
- Clean the Eccentric Shaft Sensor
- Check the catalytic.
- Motor mounts
- Low compression
All these things (as well as a sticky SSV) are on the suspect list.

Not to knock Wingznut suggestion it could well be that, but these items are also easy checks.

Wow, that's a nasty sounding engine!
 

@ Wingznut
Thanks for posting the video of that engine. My engine sounds good at idle, it doesn't have that marble in a can sound. When the sound does come on it sounds like a demented child furiously banging a couple of frying pans together. How would a sticky SSV cause the sound I'm hearing?

@WCS
I'm happy to hear that I did a good job with my post. I try to give as much info as I can when it comes to this sort of thing.

Thanks for the list of things that may have a bearing on the problem. Here's some additional info.

- @ 70k have you changed the coils yet? These are cheap to buy and easy to use HEI Ignition Tester --> http://www.fastenal.com/web/products...0245717&ucst=t
- Plugs?

I do not believe that the plugs or coils have been changed yet. I've only seen one CEL since I've had the car and that was for a gas cap that wasn't properly sealing causing an emission system fault. I haven't suspected coils or plugs as the kilometreage has been quite stable at 500 +/- 50 per tank.

- Clean the Maf

I haven't but I can do this easily. What kind of fluid would be appropriate for cleaning the MAF? Would brake and parts cleaner be OK? I have a can of that at home and could do it today.

- Clean the Eccentric Shaft Sensor

I don't believe this has been done. If there's a post on how to do this in the tech section I can do it the next time I'm at the shop.

- Check the catalytic.

I don't believe this has been done. I can pull the catalytic the next time I'm at the shop. I assume that I'm looking for a blockage in the catalytic? So shine a flashlight in one end and be able to see the light at the other? Let me know if this sounds like the right approach.

- Motor mounts

I asked Gyro Mazda to check the mounts the last couple of times I had my car in for service. Both times they told me the mounts were in good condition. I'll do a visual inspection of the mounts myself the next time I'm in the shop.

- Low compression

I'll have Gyro check the compression when I'm in for my next oil change. Is it possible that the engine has good compression at lower RPM but loses it at high RPM? Would the standard rotary compression test cover the high RPM condition?

One other thing I'll mention is that I took the head technition at Gyro out for a spin in my car and had him listen to the noise. He didn't have much to say though. Apparently they work on very few RX8s and have only done a couple of engine replacements. Are there any Mazda technicians in Toronto that are rotary specialists/enthusiasts? An independent would be great as well if they know these engines. I love my car and want to keep driving it but the nasty sounds it makes when I'm pushing it in the upper rev band is taking the fun out of driving.

Thanks again for your help!

Use electrical contact cleaner

https://www.rx8club.com/series-i-tech-garage-22/tired-searching-ess-cleaning-206687/

Correct

You will need a rotary specific compression tester. Buy your own, find a rotary mechanic or take it to the dealer. Those are your only options for compression testing

@RX8Soldier

Thanks for the info. I'll get started with the problem diagnosis this coming weekend. Hopefully I don't find the bolts for the catalytic to be a rusty mess..

sound like this per chance? or similar?
http://youtu.be/IdhAUlBywdI

No, that wasn't my video, just one I found on the intarweb. And I know your sound isn't *exactly* that issue, since it doesn't happen at low rpm's, but I just thought if it helped to identify the sound, it would help with troubleshooting.

Excellent info, wcs! I could've sworn I read somewhere that it was an exact 5000rpm open, but I stand corrected. :bowdown:

@vulcan300:

I'm having a similar problem with my '04 MT. Makes the sound when it hits 5k in any gear.

'04 purchased used in '06 with about 11k on it, now has just over 50k.
-RB intake and RB cat-back exhaust. (Noticed a significant reduction in roughness of idle with the intake installed.)
- Regular maintenance and oil change schedule followed.
- Just had the ECU replaced under warranty (thank God, it was a US$ 1200 job), but that is the only major repair work.
- Has had all TSB's performed (except the seat squeak, wish I'd done that one)
- I've had three engine floods (has had a few long periods of cold soak due to deployments) with plugs replaced each time and coils this last time.

- MAF is clean
- Cat is fine
- E-shaft reset (I've done it myself, but they reset as part of ECU install procedures.

Mine does not make that sound while the clutch is engaged and engine revved to >5k. Leading me away from the engine and "marbles in a can" and towards the tranny, but it does sound the same. I haven't noticed a significant drop in power, which conflicts a little with the tranny diagnosis right? Thoughts?

@Sephitrask

The car in that video sounds pretty close to a 2-storke chaisaw! Luckily my engine doesn't sound like that. I'll try and take a video that shows RPM and captures the sound of the engine.

@Wingznut

I appreciate the help!

@Labop

Sorry to hear I'm not the only one with this problem. I haven't had much go wrong with my car other than a defective coolant subtank replaced under warranty so nothing in our service history correlates to the problem other than taking good care of our cars.

I've thought about the transmission as a source of the noise but I think that if the transmission were making that kind of noise it would have stopped working very quickly as the internals self destructed. Perhaps it might be an unbalanced drive shaft? If that were the case I'd expect to feel the shake rather than just hear it. It sounds like something opens up around 5000 RPM and the engine character changes. It's tough to explain. I ran the car extremely hard at the track for a day ignoring the noise and pushing the car to redline repeatedly in every gear (I had the car serviced right before I did this to make sure everything was in top shape). To my surprise the car survived and I had a a lot of fun even though every time I mashed the accelerator it sounded awful.

I'm going to try all of the suggestions about and see if anything improves the issue. I also plan to run a can or two of BG44 through the engine via the fuel system. Perhaps some decarbonation will help..

I've a similar problem that I would describe as at 5k as well. My 04 MT is at 92k miles.

I had an engine replaced for "low compression" at 45k, and the symptoms seem the same. I had a previous RX-8 (04 AT) that was replaced for same problem as well.

For me it doesn't happen all the time. Sometimes it revs as smooth as butter. The only association I can make is that it happens when it's hot, but not always when it's hot. When it does happen, it is some sort of knocking above 5000 coupled with a pretty substantial loss of power.

I'm currently trying to get our dealer to be able to reproduce the problem.

@Nick

Let me know if your dealer ends up replacing your engine. I've taken the head technician at my dealership and reproduced the sound but he didn't think it was something to warrant any warranty engine work. I don't think he's all that familiar with rotary engines though. I'll book an oil change later this week and have the dealership check compression. What are the compression numbers for an engine in good shape?

@Vulcan That describes it to a T, the character of the engine changes.

I'm hoping my dealership experience is a bit different. This seems to be a good one and the lead tech knows his stuff.

@WCS Re: cracked motor mount, wouldn't we get more vibration under all conditions, especially a stronger idle shudder (as opposed to the normal one we all get)?

vulcan what part of Canada are you in?

when did the exhaust go on?

@ Labop

Have you received any response from the dealer yet? My car is in now and I hope to have compression results Monday.

@zoom44

I'm located in Toronto, Ontario. The exhaust was on the car when I bought it. I believe the PO bought it optioned with the MazdaSpeed goodies right from the dealership. To my knowledge it has the MazdaSpeed intake, exhaust and rims.

yeah that was a package offered in canada for awhile. really im thinking the exhaust has come lose somewhere "demented child furiously banging a couple of frying pans together" and is banging a heat shield etc

@zoom44

I thought the exhaust was a likely culprit and asked the dealership service technicians to look at that. They said nothing was wrong with the exhaust or heat shields. I will put the car up on a hoist myself next weekend and have a look. I'll be quite happy if that's what it is. Is the Mazdaspeed exhaust worth keeping? While the sound is growing on me it does sound like giant fart can at low revs. If there's something that sounds a little more aggressive and a little less monotonous I'd be happy to replace it.

I received my car back from the dealer. The tech spent quite a whole lot of time with my car over 2 days and his verdict is that my car "runs great". I guess the fact that it sounds like hell in the higher RPM range doesn't count for much. Looks like my next step is following the recommendations above to do my own troubleshooting. At least the labor is free :-) I'll report back on results.

So funny story, on vacation but got the call back from my service dept just now.

I hadn't heard the distinctive marbles in can sound... Until last Thursday. We were going up a steep hill, traffic suddenly slowed and I wasn't quick on the clutch so it bogged, jumped on the gas with my right toe as I was moving for the clutch to salvage it and heard the popping of marbles. Managed to get it to repeat twice, due to the car moving at slow speed while under a load on a hill, medium revs, somewhere around 5k. Called Keev at John Hine Mazda (posting a good guy for him and the dealer in a minute), and was told to bring the car in.

He had the service manager drive with me (lead tech had gone for the day) and he heard the "normal horrible sound" that Vulcan and I had described, but we couldn't reproduce the marbles. They took it in and said they would call me. Got a call from Keev today... Mazda is providing a new engine under warranty. I will have my car back by monday at the latest. Done and done.

Tech was on the line with Mazda describing the problem and his troubleshooting he had performed, he mentioned tearing down the engine to get to it and Mazda said to just go ahead and order a new one. So I think what Vulcan and I were describing might be the lead-in sounds that develop before the marbles? Never saw anything in the marbles thread about this pitch/type of sound so I hadn't thought it was related until it suddenly popped.

I'm just floored at how good John Hine mazda is, this is the second time Keev has fought for me on warranty stuff instead of just taking the easy route, good service dept, takes care of their customers. Last time it was a new PCM. My car is funny for their average customer. It's originally from louisana, I bought it in Florida, serviced in it Washington and Mazda and Keev originally thought it was California emissions and power train warranties (not knowing the history), but Keev ran the vin at my request and sure enough it falls under louisana regs for warranty period.

Keep taking it back Vulcan, or take it somewhere else... Good luck man.

@Labop

Congrats on the new engine! Hopefully the new one treats you better than the old one did. I'm guessing there is plenty of info on here about how to treat an engine right from the start, so you should have a great car to drive for the foreseeable future.

I have an interesting tale to tell of my own. After getting my car back and told that they found "nothing wrong" and "didn't do anything" to my car other than an oil change I expected the engine to sound just the same as always. I did have the car out yesterday night but didn't push it enough to hear the noise. Today on the way to work I was driving with some spirit and noticed that the throttle response of the engine was better. I decided to put it in manual and see what was what, and when I ran the engine up to red line found that the sound had pretty much disappeared! Assuming it doesn't come back I'll be a happy camper. I called the service advisor and asked him to chat with the tech and find out if he did anything at all besides waving the magic wand he picked up from Snap-On recently :-) If I find anything out I'll report back.

I'm still going to do the maintenance suggested above to ensure that things stay good.

Got my car back and she sounds and feels amazing, like she is brand new. I about had a "crisis" (Top Gear reference) when pulling out onto the freeway. I also had the clutch replaced, and hadn't realized how bad it had gotten until I had a new one installed. They didn't charge for labor since it had to come out with the engine, and the throw out bearing came with the engine, so $80 bucks off the replacement clutch as well. Double score, or is that triple.


These are the relevant entries from the service log. Thought I'd share in case your problem comes back Vulcan. I'm hoping it doesn't come back for you, so good luck brotha.

#1 Customer requests diagnosis. Complaint stated as: growling/rattling noise under hard accell at 6000 RPMS - Service director duplicated with cust.
#2 Customer requests diagnosis. Complaint stated as: marbles rattling in a can noise engine area. Accell uphill 5 MPH under load - Ride with service director to duplicate.

----

Compression test results (performed three times):
FRONT ROTOR: 1=880, 2=870, 3=900 @244 RPM (which I'm taking to mean 2,440)
REAR ROTOR: 1=760, 2=730, 3=740 @240 RPM

------

Inspected misfire count in Mode 6 and found front rotor has 335 count at last 10 driving cycle, rear rotor has 305 counts at current cycle. Hotline found front/rear rotor exceeded compression differentiation max spec. Hotline tech recommended and authorized engine replacement.

Nice update.
Thanks for the info Labop

Maybe I can shine a little light towards you as well. I've been having similar grinding/growling issues at 5,000RPM and up but it wasn't the sound of the MOAC(Marbles-In-A-Can)/SSV issues. I began premixing to see if it would help the issue and I almost immediately noticed a difference( roughly 40 miles later with 4~oz of Pennzoil Marine Plus TCW-3 2-Stroke Oil on a full tank of gas). The sound was still.... slightly present but much less pronounced. Over the course of the past couple months I've experimented with tanks of gas having no premix and the sound/issue almost always resurfaced loud and scary. For a while I thought that perhaps my OMP was dying(no CEL though), or that my OMP lines were clogging and my engine wasn't getting enough oil mixed in by itself.

Long story short premixing seemed to calm my issue, read on for the potential results of the issue.

Extended Story: I've been nearing 100k Miles(currently at 99.7~) so I figured I'd swing by Mazda and have them run a compression check and see if I had the latest PCM flashes before my warranty was up.

They(Montgomery Mazda in Charlotte, NC) ran the compression check this morning and I was told that I had bad compression (don't know the exact numbers at this time, I remember rotor 1 was maybe 6.7 at the highest of the 3 numbers, and rotor 2 was roughly 7.5~ something). They said they wanted to run some more tests and that if those failed I'd be getting a new engine. The tests failed, and I got a call saying that they had ordered my new engine and that I should have my car back by the end of next week. I guess try premixing and see if chills your issue, driving on it too much might lead to failing compression.