RX8 Emissions Failure Help

[_Lewis_]

Hello, just bought a 2005 RX8 that had a failed MOT , The rest of the MOT is an easy fix but the Lamdla Emissions (Exhaust Lambda reading after 2nd fast idle outside specified limits) is proving hard to fix at home , I have checked the spark plugs they are all working perfectly but when you run the car there is a distinct smell of petrol , I have been doing some googling and i guessed it was the lambda sensors but after taking out the post cat sensor and looking to see how it looks , It looked ok just a little dust on the outside i then tried to get the pre-cat sensor out but i cant fit any wrench in there to get enough pressure to get it out. Also the inside of the catalyst looks like this on the back of the car side of the cat and on the engine side it looks like [url|https://thumbsnap.com/hxBoMk73[/url] this. Any help would be greatly appreciated as i can't wait to get this beast on the road.

[cib24]

Cat looks clogged. That will eventually lead to engine failure. Where are you located? I can recommend a specialist near you that can help with the cat and the MOT.

[cib24]

In the meantime, don't rev the car hard with a clogged cat like that.

[Nickp82]

Yup, cat has started breaking down, this is common on RX8s particularly where old or cheap ignition parts are fitted.
Many owners either run a decat (fitting a working cat back on at MOT time) or hi-flow cat.

[lilwashu]

Your ignition coils have probably failed, they are the primary cause of the cat melting (and cause a petrol smell). If not replaced the new cat will fail also.

Beware fake ones on eBay.

[_Lewis_]

cib24 said:

Cat looks clogged. That will eventually lead to engine failure. Where are you located? I can recommend a specialist near you that can help with the cat and the MOT.

Hi, sorry I could not respond quicker forums we closed, I am in Fife Scotland. Hope this helps

[cib24]

There is someone in Paisley named Ben that may be able to help you but the best way to contact him is via the Scottish RX-8 Facebook group.

From the RX-8 forum which would be very useful to you and I suggest you sign up so you can ask all of your beginner's questions:

https://www.rx8ownersclub.co.uk/forum/viewtopic.ph...

"I'd get in touch with Ben (minisaki) - probably easiest through the Scottish group on Facebook. He has been busy swapping stuff from his old RX-8 to his new one, but if he has time he would be able to put a new cat on. He is in Paisley."

[untakenname]

As has been pointed out above the coils (and possibly leads) are failing which in turn has lead to the CAT failing, replace the coils with genuine Mazda rev C's (around £40 per coil from japan) or upgrade to RRP coils https://www.ryanrotaryperformance.com/shop/rrp-per... as they are plug and play, the other GM coil upgrades need the dwell timings changed via a remap.

I would knock the molith out of that CAT if I were you as if it collapses completely it can take out the engine or even worse set the car alight.