VERY dead rx8.
 

Hi all, my name is Stuart, and I would appreciate any help and input with this issue.

I just bought a 2005 rx8, 67,000 miles. beautiful red, beautiful to drive, beautiful sound, does everything right (bought from a licensed dealership). Had it driving perfectly for two days, yesterday (yes I've had it for three days) while i was driving it, there was a slight rattle, barely noticeable from 5500-6500 rpm. after about three miles the slight noise became very dramatic, the performance of the car dropped astonishingly and I barely made it back onto Fort Bliss before it died for the 5th time and wouldnt start again. I tried to start it as though it had flooded (i.e. taking out the fuel pump fuse, flooring the accelerator and cranking systematically) but no success. I have a 2 year powertrain warranty on it THANK GOD and the dealer is picking it up to take it to the shop today in an hour or so. I would really appreciate any insight as to what the issue might be, what will need to be done, and how I might prevent the same issue from happening in the future.
Thanks for any help
Stuart, 68W US Army

Stuart,
First off, thank you for serving our country. :patriot:

As for the car, sorry to hear your ownership is getting started off on a shaky start but hopefully it's nothing major and they can get you back on the road soon.
The odd thing is the rattle.
I wonder if the catalytic broke apart and the ceramic pieces were bouncing around?
Any CEL?
any other symptoms you noticed?

I usually recommend checking the catalytic first and then performing a simple compression test, that should tell you whether or not you've lost compression because if so, you'll soon need a rebuild.

Well i just went out and cranked it again, it turned over and I got some revs out of it but it died pretty quickly. The rattling is extremely loud and sounds as though its coming from directly underneath me, not the back. I have the number of the shop that the dealership is going to send it to so i can get the result of the compression test, etc for myself and not hear it through a third or fourth party.

check the cat asap befire u start it again..... could be the cat is gone

Would the cat being done make a rattle that loud AND kill it? Do you mean if it's just too clogged or something? What do you mean by "went out"

should a bad cat make the car die?? oh maybe if it is too restrictive in some way????

I've never had that kind of a problem from a cat from any car or motorcycle for that matter. Please, if you don't have something to say that will help, just don't post on here. Thanks.

if the cat 'goes out' (aka it breaks up and clogs) it could cause the motor to stall out.
I think maybe that's what lvis and wreakloose were implying.

Hello. The RX-8 isn't like any car or motorcycle, so there's that.

You asked for any help or input and then you have an attitude when someone offers input.

If someone takes the time to respond to you, it should be appreciated and taken at face value.

I have had plenty of experience in exhaust shops and can tell you for certain that rattling and poor performance are classic signs of broken strata in your cat.
It will break up and get lodged in your exhaust pipe or muffler and force backpressure into your engine.

Good luck and appreciate any input someone offers you.
Otherwise, you'll likely be ignored.

The responses posted here besides Jedi; either they're trolling or an incredebly stupid keyboard warrior.

If you didn't buy the RX-8 from a MAZDA dealership, you will have a hard time getting the Cat-converter replaced or even a proper engine compression test. We may not even know how long this problem have lingered before the title was transfered to your name. Follow what Jedi have suggested; your next agenda should be a visit or call to MAZDA about the date of purchase of your RX-8, you may still qualify to have your engine replaced under the 100,000 miles/8 year warranty for a remanufactured one. Realistically speaking; your car will sit in that dealership back lot long before you're back here asking about getting a reman' engine for your car.

not to step on ya toes grace but its 100,00/8 year warrenty isnt it even though it may still be in it anyways XD

*fixed :bigok:

Scuba, nice way for a noob to thank ppl for trying to give you advice.If you bothered to search, you would have found many posts that relate to "cat failed,choking exhaust"
9K, no link for the noob?
Puppet, wtf are you talkin about Willis ?
Grace, please explain your 1st line in your 1st post, at the same time, tell me what else is prone to rattling directly under the driver, which causes other problems and prevents the motor from starting, talk about a troll !

Scuba, the responses WERE trying to be helpful, and they were even in the right general direction. A cat failure can indeed do what you are describing.

I personally would point the finger at internal seal failure in the engine, but it is possible for a cat to do that as well. The problem is when the cat clogs up, it basically seals off the exhaust stream, soaking down more and more engine power until the engine can no longer physically move more exhaust into the exhaust stream. Pack it up enough and it will choke the engine off.

The engine is 8yrs / 100,000 miles from the date of first purchase / in service date. The cat warranty is 8yrs / 80,000 miles from the same point
His aftermarket warranty may cover something else entirely.

Hello. What exactly is it about my response that is incredibly (note spelling) stupid?

Why do you feel it is necessary to insult people?

You could have just as easily said you believed the other posters were wrong and given your reasons why.

Lol I appreciate all the input everyone, not trying to cause any disputes to start going off, I HAVE read about different problems that it could have been, I just have a hard time imagining the rattling is coming just from the Cat, it was nearly hurting my ears. And that it had been driving perfectly for two days and then on the third I made three miles before the noise was really REALLY bad and the car had died for the last time. I plan on gutting the cat as one of the first things I do to my RX-8, presumably that will solve my issue?

ADD* would solve my issue IF the seals in the rotor aren't already done for

With that new description, it solidifies my believe that your engine is blown. A cat failure won't cause that level of noise. Apex/side seals flying around in your engine could.

So odds are anew engine is going to need to go in?
Also, is there something that I might have done to cause this to happen, or was it only a matter of time?

Both? :)

The rotary engine isn't a very durable engine to begin with, and it's also fragile. It is simple for periods, or even moments, of neglect to cause severe lasting damage. Even if everything is done perfectly to maintain the engine though, factors outside of your control (like build quality and just the nature of a rotary) could very well kill your engine anyway.

See my new owner's thread for more details and information around this: https://www.rx8club.com/rx-8-discuss...t-here-202454/

Will do thankyou. same to everyone.

Hi Scuba.
There has been discussion about low fuel during hard left turns damaging seals that I had concerns about.

I was afraid I had damaged my engine by routinely driving on low fuel.
Could this have happened to you? That's one possibility.

Thanks RIWWP.
My one finger hunt & peck typing did me in again.

BigCajun,

You are referring to fuel starvation from low fuel levels in hard left turns. The fuel sloshes to the right side of the tank, over the hump in the middle, leaving the pickup in the left side of the hump dry. While this is never a good thing, the risk of fuel starvation increases with how much throttle you are applying and increases with higher RPM.

You won't do general damage to the seals just from being low on fuel, or even low on fuel with left hand turns. Any damage from fuel starvation would be because the ECU is expecting X amount of fuel, and it gets far less than that, leading to a lean spike and detonation, which could shatter an apex seal. Fuel starvation without engine damage would be like a momentary hard power cut or engine completely shutting off but can re-fire without much effort. Fuel starvation WITH engine damage would be lots of bangs, rattles, etc... as the seals rip up the interior of the engine.

For this particular failure mode, there isn't any in-between. It either happened or it didn't.

This failure mode is also more common on a fuel pump failure than it is on high G left turns, in part because high G left turns are rarely at full wide open throttle, and it's not a 100% sure thing that you will have a fuel starvation even if you are nearly out of gas.