I just need to reset code and pass inspection, then it will all be replaced with accessport and a new borla exhaust with a nice midpipe for maximum orgasmage.


Hi everyone.. thanks for taking the time to read this.. Let me start by saying F** DAMN SH*T i just wrote a novel on this problem and then went to post and it timed me out and i had to re-log in. Oh well lol.

So i recently purchased a 04' rx8 from my buddy. He has kept this car in primo condition i have known him since he was a baby. He is a mechanic and this car was his life. Due to a recent harsh divorce, and some other financial reasons he sold the car to me.

The car right now is throwing a CEL of p0420. Here is some backround information on the car, as well as recent maintence done and future plans for the car.

04' mazda rx-8 , 87.5k miles. Sparks wires and coils changed every 15k miles (he was religious about this car) oil was topped off probably once a week, car never went 3k+ miles without having a full change including filters etc. No recalls were reported on this car, nothing faulty has ever happened to my knowledge (i was with him everyday for the most part) other than some simple starter problems (was replaced at about 30kmiles) car runs hard, pulls harder, and is overall is sick condition for having nearly 100k miles. Compression tests came back good. Cat has never went bad, or ever needed to be serviced or replaced, but he did drive this car hot (what i mean by hot was he drove this car the way she was ment to be driven normally having a very good time on long windy roads.) Just about this same time last year, the CAr threw a CEL p0420 just like it is now. He replaced the Rear o2 sensor and problem solved, he stopped driving the car about 3 months later and has been sitting in his driveway ever since up until about 1 month ago. He did in that time period start her and run her around for 20-30 miles atleast once a month. About 150 miles into it not sitting around anymore the CEL came on throwing a p0420. I figured it was bad exhaust hardware and a heavily worn gasket, Replaced those both. 62 miles later CEl came back on throwing the same code. I'm very aware that this can be a bad CAT but i will be honest with you i have no intention on keeping or replacing it. I will be using a midpipe with a borla exhaust in about 3 months when i get my 14k bonus check from work. I have taken both front and rear o2 sensors out and cleaned them. the coils, plugs and wires have been changed within the last 4k miles, oil change + filter within the last 100 miles. Does anyone have any good solutions on dropping that CEL, I am not against spending money but i would rather not, as i will be doing basically a full rebuild of the exhaust and the undercarrage of the car has all been replaced within 40k miles. I have been reading about the Spark plug foulers fix, drill em out and plug them into the cat then the o2 into them. Just as a temp solution and it is said to have a 95% success rate in 8's.

All suggestions are highly welcome and i appreciate every word typed on this thread.

Thank you so much for your time riwwp, i know u will be visiting this post mr postmaster. :D

Thanks to everyone though,

Rich.

 

already told you in the other thread

there is no way to physically manipulate the downstream o2 to prevent a CEL

even if you do something and you think the CEL isn't thrown, your readiness monitors will still be 'not ready' so you will not pass emissions.

 

Yes i know.. i just moved threads because DIY was not the proper place to post..

Is there any other products other than a accessport i can buy to fix it?

 

Sure, an aftermarket ECU

 

How about potentially cleaning the Cat, i'm not sure what to clean it with but i heard that this can possibly work.

someone suggested pouring lacquer thinner into my gas at a half tank and running it for 150 miles. but i do no know how this will affect the car. Any thoughts?

 

have you actually taken a look at the cat to see if it is blown apart? Just disconnect from the header, and unhook the exhaust hanger that holds the catback, should give you enough leverage to peek inside.

I dont know about you, but I personally dont like to just start pouring crap in my gas tank when i dont even know what is causing the problem.

 

I hear you, and i really appreciate you giving thought into this.. is there a thread on how to remove it. I agree though about pouring random crap into my tank. How can i tell if it is blown apart or not? I'm not even sure if its the cat causing the code but the o2 sensor was replaced and used for literally 3 months before the car sat for 7 months. Maybe i can try to post some pictures up. What would be the steps u would take to try and diagnose the car throwing that code.

 

You're wasting your time ... he doesn't want to know what is really wrong / or find out.

Have fun pouring that witches brew into your gas tank

 

No no no please dont say that, i really do want to know whats wrong, i just don't know where to start, all i have to go off of is what i read. that's why i asked. if i had no intentions of fnding out or fixing the problem i wouldn't waste my time posting.

 

i just don't plan on keeping the cat on the car so i don't see the need in replacing it.

 

Your title suits you well ... not sure how many more times we need to tell you. Drop down the cat and take a look ... i dont care if you are going to keep it, toss it, burn it, launch it .... UNDERSTAND what the issue is before attempting a SOLUTION ... because honestly how can you have the latter without the former.

 

Haha okay i deserve that one so thats fine.. i wanted to update you on what i did last night (and it sure was a task.) I did exactly what you told me and pulled the cat, inside it was terrible. It was so blocked up you would think it would explode. But glady it did not (if thats even possible im not sure.) I was going to just try and clean them + the o2 sensor but i decided, why do things wrong the first time. Yes i do plan on getting rid of the cat in general, but i figured, buying a new one would be good because i can always re-install it for inspection purposes. Hopefully replacing the bad cat will get rid of the CEL. Are there any other reasons for this code in specific that i should check for and heres a quick list of things that i've checked / fixed.

-checked for exhaust leaks, found out gasket was bad. Replaced gasket and replaced the exhaust hardware around it.
-Replaced Rear o2 sensor less then 10,000 miles ago, so instead of trying to replace it again i just cleaned it real good for now. All the wires were perfectley in tact and everything was fairily clean.
-Took of the cat, it was worn and torn and looked like there was concrete on the inside. (i assume thats bad since its similar to a filter you should see some fencing type stuff)
-Ordered a new cat.

OF course if that does not work, i will see what is next.. any chance it could be the front o2 sensor?

Yes im a 8 noobie, but i want to learn, and i want to ask alot of questions to learn. With that beign said i Really appreciate everything.

 

Thank you by readinding this thread I will pull the cat and take a look see
The code says its a bank one low efficency, bank one to me means # 1 o2
Ty I will pull it and look into the cat
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