Speedy3102

Hi guys, I'm a new member and a new owner of an 05 RX8. Have previously owned RX7's, so not new to a rotary.

I have a glowing cat and I know it's been cover extensively, but mine is a little different since the cat in question is brand new. Apologies for resurrecting an old topic.

When purchased the vehicle had a CEL due to an o2 sensor (not sure which and kicking myself for not asking. I was able to negotiate new 02 sensors and a new cat with the purchase. I installed both new sensors and cat (old cat appeared to be newer and in good shape). CEL cleared on power up and hasn't returned. Shortly after replaced plugs, wires and coils (Autozone coils). When removing the old plugs found the trailing and leading plugs on the front rotor reversed. Don't know how long it had been that way if if this would cause permanent damage.

After disconnecting the battery for a day to clear memory I took the car on a couple of 5 mile drives to relearn the the fuel maps and after my return I found my new cat glowing red hot around the 02 sensor.

Car idles good, no check engine lights. I have since replaced the coils again with factory parts, second set of plugs, verified grounds ok at the coils. Cleaned MAF and ESS. Pulled the cat and everything appears to be in tact (checked hidden areas with a borescope). Reinstalled today and still got a faint glow around the 02 after a short ride.

Any advice is greatly appreciated.

Thanks

RX8Soldier

iTrader: (24)

What is the brand of the cat and ignition components? Have you verified all coils and plugs are firing?

Loki

iTrader: (1)

Glowing and not obviously broken cat points to excess fuel. What about the rest of the exhaust system? Any chance pieces of an older cat are lodged in the muffler and blocking flow? Any rattles?

What are the fuel trims if you can read then via OBD2?

Speedy3102

Thanks very much for the replies.

The new cat is an OE Mazda replacement from the dealer. Plugs (RE7CL, RE9BT) and wires are NGK parts purchased from Auto Zone, coils are OE Mazda. I don't own a tester to verify all plugs are firing, recommendations on one to purchase? Have had 2 sets of plugs, wires and coils in the vehicle with same results.

Excess fuel seems to be a potential as it seemed to run rich after the ignition parts change and slight smell of unburned fuel when I pulled the cat yesterday to check for damage/clogs. Strangely the feeling of running rich seemed to start after the ignition parts were replaced.

Clogged muffler was a thought due to age. I pulled it , but didn't find anything between the mid pipe and muffler. I did replace with a racing beat cat back prior to the latest test today.

I don't currently have have an OBDII tool to read fuel trims, can you recommend one? I do have access to a VCM diagnostic tool at work, but do not have a Mazda IDS license.

Assuming I'm getting unburned fuel into the cat, what are potential causes? Poor spark

Loki

iTrader: (1)

Leaking injector, poor spark, incorrect fuel trim, incorrect spark plug wire connection, bad MAF or some aftermarket intakes. Any $15 OBD Bluetooth adapter off Amazon will do, but if you have VCM, surely it can read basics like fuel trims without a license?

Speedy3102

Loki, thanks for the reply. Probably best if I get an OBD scanner to see what everything is reading and verify spark before I throw more parts at it.

Appreciate the info.