Hi my rx8 was losing power and even dieing on me ive changed the ht leads got it running then the cat was glowing red(almost on fire) i have now replaced the cat(new) and it is still glowing but just around the sensor any ideas what the problem is??

 

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https://www.rx8club.com/rx-8-discuss...t-here-202454/

If you want help then provide year, model, miles, maintenance history etc

 

OP, Please do not post the same question in multiple threads.

 

Your ignition is shot. Ignition is all 12 pieces: 4 coils, 4 wires, 4 plugs.

Even 1 of the 12 failing will mean that the rotor that it goes to will not be having proper combustion, and there will be excess fuel AND excess air "left over" that gets shoved out into the exhaust. This mixture is still flamable, and ignites there under the high exhaust temps. The constant dumping of air and fuel and subsequent burning acts like a blowtorch in your exhaust, superheating and slagging the cat and starts the metal piping glowing as well.




I assume by "leads" you mean wires. So now you need coils and plugs as well.

 

Hi thanks for your reply when i changed the cat i didnt change the lambda sensor as when i pluged the car in to test for any faults it was clear.will it need replacing aswell as the coils and plugs.

 

You're welcome.

 

Probably not if you're not throwing a code.

 

hi thanks again for the reply..... why didnt the coils show up on the test if they r faulty and will i need to change the spark plugs aswell?

 

The official Mazda coil test will not detect a failing coil, only a completely failed one. It is largely useless for our purposes since you will have misfires, cat damage, plug fouling, etc... while a coil is just failing before it actually fails completely.

The problems are also cascading. If a coil is the first to fail, that plug won't be firing enough, and the excess gas will foul the other plug in that housing. That other plug will have trouble firing, and the coil that leads to that other plug will start failing faster because it is designed to release it's charge, and it can't cleanly any more. Same with a wire failure, it will lead to both coils on that housing failing prematurely.

So yes, replace the plugs as well.