Sooo fairly new here, but have a question. I've had my 8 for about a year now and I just noticed that sometime after driving my catalytic converter is red around the o2 sensor. Now I haven't ever driven in any other 8 but mine but it seems to be running just fine. No check engine lights or anything popping up. Just the random red cat? Is this an early sign of the cat going bad or could it be something else. I have a Warrenty on it but I don't want to have to take it in and pay for a diagnostic and nothing be wrong. Thanks in advance!

 

Heya, I'm sort of new too, but I remember reading that a glowing cat means that it is in need of a change. Also I read that it could be caused by failing ignition. : "Symptoms of ignition failure include: Power Loss, mileage drop, unstable idle, bad idle, inability to idle, shaking at idle, unstable high rpm, misfiring, flashing CEL, coughing engine, glowing cat, flooding, inability to start, inability to pass an emissions sniffer test, and just about anything you can think of where a weak or missing spark causes problems"

source:
https://www.rx8club.com/new-member-f...t-here-202454/

 

Hmm if the cat is glowing red at any point it is more than likely clogged, or getting pretty clogged. There's not any reason for a catalytic converter to glow unless it is being restricted.

Only way to really check is to look inside and check the honeycomb looking elements.
Good amount of work to pull it off though

 

Red cat = Bad. Read the new owners thread.

 

Had the same issue, problem was clogged injectors, had them bench flow and issue is now gone

 

+1 for bad catalytic converter

 

Thanks for the responses. Called my local Mazda dealer and they don't seem to want to help. Said its probably just fine but they would run loads of diagnostic teats which wouldn't be covered on the Warrenty before doing anything. Shouldn't the diagnostics be covered if obviously something is failing Ben though according to their tech the red cat isn't always bad.... Thanks again

I also forgot to add that during winter as the car warmed up I would get the rotten egg smell if it was driven before reaching normal temp. Once it hit operating temp the smell would go away.

 

Hello, glowing cats also could mean misfires, resulting in unburned fuel igniting in the converter.
Misfires should result in a CEL or flashing CEL, although I don't know if it always does.
I would suggest getting codes scanned at a parts store for free.
Another way to check ignition is with a timing light, though I've never done it.
Dealers will never want to do anything for free.
If you firmly insist it should be covered they may give in, but I doubt it.

 

Well, are you still having that rotten egg smell? If you are not using 2-stroke premix and still have that smell, you should place your car on a lift to remove the CAT and inspect the honey comb. The smell and the red glow ring around the O2 sensor are good indications that you should check your CAT, despite not having a CEL.

What year and how many miles do you have on your car? I may be wrong (without looking back at the source) but if you car is within 8 years/80,000 miles; you can have your CAT replaced under that warranty. Mine clogged at 88,000 miles and showed cracks on the honey comb at 168,000 when I had my reman' in place of the original factory engine. So, I would think that around 80,000 miles is the average life-span of an OEM CAT with our cars.

 

Misfires killed mine at less than 19k.

 

What makes it glow is unburned fuel getting burned. That is the source of the heat.

If you have not done plugs and wires, now is a good time. Same for MAF sensor and ESS.

If you do that, and it stops glowing, you might save the CAT, you will also likely see MPG up.

I would start with the cleanings first, then coils, then plugs.

 

Alright so I decided to take to a dealer just to get it checked out. Seems the cat is ok, they said it looks like its needing new spark plugs, still has the original ones. Looks like you all had it nailed thanks again! Also from what I've read it seems like most people stick with the plugs from the dealer right? The kit is like $170 so just wanna make sure. Thanks!

 

$170 for just the plugs? or is that with wires and coils?

If there is an Advance Auto Parts near you, I know you can get plugs cheaper (look for coupons).
NGK makes them and they should be the same thing from the dealers.

 

Ok, I guess I have to post this again...
Advanced Auto Codes
Note that motor oil and other exclusions apply. The coupons (which do not stack):

20% off sitewide via code "P20"
$10 off orders of $30 or more; $25 off $70 or more; $40 off $110 or more via code "A124"
$20 off $50 or more via code "ES123"
$30 off $90 or more via code "HUGE30"
$40 off $100 or more via code "TRT41" "DOW19"
$50 off $175 or more via code "HUGE50"

 

Ahaha, yeah that's your guy!
I remember seeing that post and got plugs the next day, was like $50 bucks.
Thanks again for that info!

Oh I might add "TRT30" for 30% off sitewide, Limit of $50 off

 

Alright, I tried looking through the New and Potential owner thread and I didn't see it. Which NGK plug will I need?
Buy NGK Laser Iridium Spark Plug (RE7C-L) 6700 at Advance Auto Parts

Buy NGK Iridium IX Spark Plug 2669 at Advance Auto Parts

Buy NGK Laser Iridium Spark Plug (RE9B-T) 6701 at Advance Auto Parts

Thanks!

 

Search be your friend:
But you will need 2 of the RE7C-L (leading)
And 2 of the RE9B-T (trailing)
Assuming you have a series 1 RX-8 (not sure if this changed for series 2)
Edit: you do have a series 1 lol just saw you have a 2007.

If you are planning to do them yourself (which I would suggest since it's very easy) just remember the "L" for lower and the "T" for top if memory serves me right lol.

Hope that helps

 

Hi Hellsfire, it's a bit more of a drama getting the various bits and bobs for a tune over here. I'm off to Hamilton to get a dyno done courtesy of Brettus and a tune. I guess I'll find out what I need then as it wouldn't be practical to buy it now and take it down. Especially as I'd like to BHR it and the delivery time wouldn't be quick enough.
I'm a **** mechanic so I have to rely on the kindness of others. Luckily I know a lot of bloody good blokes....and I make a mean coffee/beer!!!!

 

Oh hey StephenT,

Good to see ya buddy! Yeah I know what you mean about the mechanic stuff haha, heck even though I have been wrenching for a couple of years now, I am still afraid of breaking/forgetting stuff
(I just call it a weight reduction when I forget some nuts/bolts lmao)
Let me know how the trip and tune goes

Also to the OP, as StephenT mentioned if you are going for the whole ignition replacement - BHR makes a great kit
(bit pricey but a great investment as you wont have to keep going through ignition coils every 40k or w/e miles).