Effects of a a failing Catalytic convereter?
 

Hey guys,

My car sudenly stopped being able to hit the high rpm range and would would pretty much cut off at about 7k rpm, but the rest of the rpm range was fine. Then shortly after all of my rpm range began losing power and I could only hit 6k rpm before it wouldnt go any higher. Now I have next to no power in any of the rpm range and and cant get past 6k rpm. The dealership diagnosed the problem as the catalytic converter which is what I thought it was...

With the symptoms I have mentioned does it sound like that was a correct diagnosis? slowly losing more and more power and max rpm declining..

Or does it sound like loss of engine compression?

Thanks guys!!!

Either situation would cause a loss of power...You should have a compression test done asap...I felt a loss of power it my 8 not too long ago, played doctor, and diagnosed it as my Cat...Therefore, I gutted the b****...Talk about a happy ride.

Here's an easy way to check...Go out at night and cruise around until your engine is at a nice, high temp...Pull over, and check under your car...If the cat is glowing, it's dying.

My symptoms weren't as bad as yours though...If it is your cat, you need to get that thing off quick...It's just placing back pressure on your engine...If the problem isn't your engine, and you keep the cat on, it will be your engine soon ;)

How old are your coils, plugs, and plug wires? Start with these items. Many cat failures are caused by coil, plug, or wire issues. If these are in good shape then check to see if your cat glows like lta_ds_fs7 suggested.

The cat doesn't always glow. Or it might not be noticable. A better way to check it would be to take it off and check. But if your dealer is saying it is the cat then it probably is. They don't usually check the cat if the light is not on. ^but yes do check your ignition system because more than likely thats why your cat went. So make sure you change it all at once. If your under warranty have the dealer get you a new cat if youre not then I suggest gutting it, mid pipe or high flow cat. The stock ones are expensive.

Changing the plugs coils and wires, was the first thing I did. The problem still remained so I took it to mazda for diagnosis. They said the code called for catalytic converter so they would send the numbers to mazda for warranty approval. Its now been 3 weeks and they still havent called me back since they sent me on my way. I called them back to find out whats taking so long, and they said that it can sometime take weeks or months to get approval from mazda (I call BS) and they claim that I crossed the wires when i installed the plugs coils and wires which may voide my warranty. HUGE BS. I have looked at my cat before and I have never seen it glow...

Crossing the wires on a lot of cars will not let it start. I don't think thats true with the rx8 but it certainly would run like crap. That is a load of bs. If they don't do it take it to a different dealer or call Mazda yourself. The cat probably went bad because of bad coils and plugs but now that you got them changed just get your free cat. Just make sure you fight them on it because otherwise it is very expensive

Thanks silver 6 really appreciate it!

No problem. Good luck.

my car also seems to lack power after driving it a while on hot days deres a nocking sound under the car den its just goes away after a while and the car feels fast again i just changed the plugs and they were bad but it still does it but not as bad what can it be?

A knocking sound? I would say pull off the cat and take a look. You could check first to see if its glowing though. Any cels?

...have a compression test when your at it, just to make sure it's not the engine.

MazdaCustomerAssistance@mazdausa.com

Send email to that address
i sent email 17 Jan 2011 to ask about any open recall on my 8 and got back to me on the January 18, 2011 and got this

Thanks for contacting Mazda.
If you would like to provide the VIN number for the RX-8 I would be more
than happy to look up any open recalls for you as recalls are VIN
specific.Again, thank you for contacting Mazda.
Regards

sent them the vin that day and got a reply back with a pdf of all open recalls on my 8 that same day lucky i did cause couple months after i got that my clutch bracket cracked and was under warranty went to my dealer here in guam and they tried to give me BS like it wasnt under warranty so i got that pdf printed out and told them i got that from the main mazda.
then they told me they will call when part comes in.

Then just the other day a year after i messaged mazda i used the same address from 2011 to check if my cat was under warranty and got back a message less than 5 days later
best customer service i have ever seen other than everyone on rx8 forum who have helped me out with out this forum never would have kept and got my 8 running again lots of these guys here know their S*** and should be the ones working on rx 8's at the dealers

Basically happened to me last year, car suddenly became bogged down and unresposive. My check engine light came on with a misfire code so mine was also plugs,wires,coils.

With the 8, everything has to work together, basically bad coils will kill your CAT over time...

The dealership I brought it to was excellent, most of the stuff changed was under warranty. The CAT basically fell apart when they took it off...crazy.

I'm not having the power loss issue but my car is throwing a CEL and saying system too lean, it's not reading any voltage from either O2 sensors accept for a little blip every now and again, car has plenty of power starts right up, I just don't understand what's going on, I just replaced the O2 sensors too! I don't have the $500 it takes to drop it off and get it diagnosed at Mazda either, it does knock and is a little louder than most 8s though and there is a weld on the cat which I don't understand(i got the car used) because they sell the cat as a whole unit, any suggestions?

The knocking is coming from the exhaust, not the engine, I'm very aware that rotaries can't really knock

Rx8 won't start
 

I just replaced the coils, wires, and plugs. I was going down the road and it ran fine for a little while then it seemed as if it was bogging down then all of a sudden boom I look in the rear view mirror and I see sparks I think is was the cat and it clogged up. Will a clogged cat cause my 8 not to start.

Nope. I hate to say it, but that sounds like something much worse than a clogged cat. What happens when it doesn't start?