hiroyukiiwaasa

Hey guys.

I'm in need of some help and I figured you guys know the rx-8 better than anyone else... Kinda got two issues going on right now...
1. CEL P0139 turns on and off usually at least once a day... (P0139 = Rear HO2S Circuit Slow Response)
2. Lose power at 7K RPM and cant get much higher.
3. (not a big deal) Car starts fine when cold, but sometimes takes a little while to turn over when hot.

From researching this website many have said the solution to this loss of power is to replace plugs, wires and coils so I have order the NGK Laser Iridium Plugs and NGK coils and plugs. They should be arriving this weekend and I'm really hoping that will take care of the loss of power. My CarMD told me that replacing rear O2 sensor is the most likely fix for my CEL P0139. So I am in the process of finding a replacement 02 sensor for the best price I can.

Advise:
So Ive been hearing different things from different forum member and Im really confused and would like some help before I keep throwing money out the window on fixes that may be completely irrelevant.
1. Ive been told that it sounds like my engine compression could be going which means time for a new engine, but before I go and pay for a test, I should replace the plugs coils and wires, which is what I'm in the process of doing right now.
2. Ive also been told that its sounds like I could have a bad Cat. (If it was a bad cat, wouldn't my CEL stay on and not turn on and off daily?)

Is there anyway for me to determine for sure what the problem is with my car regarding the issues I have mentioned? And also how to fix them? Im an 18 year old and cant afford to throw out money for possible fixes that may be completely irrelevant, so whatever help you guys can give me would be extremely appreciated!!!

Thanks so much!!!
Brandon

hiroyukiiwaasa

Hey guys.

I'm in need of some help and I figured you guys know the rx-8 better than anyone else... Kinda got two issues going on right now...
1. CEL P0139 turns on and off usually at least once a day... (P0139 = Rear HO2S Circuit Slow Response)
2. Lose power at 7K RPM and cant get much higher.
3. (not a big deal) Car starts fine when cold, but sometimes takes a little while to turn over when hot.

From researching this website many have said the solution to this loss of power is to replace plugs, wires and coils so I have order the NGK Laser Iridium Plugs and NGK coils and plugs. They should be arriving this weekend and I'm really hoping that will take care of the loss of power. My CarMD told me that replacing rear O2 sensor is the most likely fix for my CEL P0139. So I am in the process of finding a replacement 02 sensor for the best price I can.

Advise:
So Ive been hearing different things from different forum member and Im really confused and would like some help before I keep throwing money out the window on fixes that may be completely irrelevant.
1. Ive been told that it sounds like my engine compression could be going which means time for a new engine, but before I go and pay for a test, I should replace the plugs coils and wires, which is what I'm in the process of doing right now.
2. Ive also been told that its sounds like I could have a bad Cat. (If it was a bad cat, wouldn't my CEL stay on and not turn on and off daily?)

Is there anyway for me to determine for sure what the problem is with my car regarding the issues I have mentioned? And also how to fix them? Im an 18 year old and cant afford to throw out money for possible fixes that may be completely irrelevant, so whatever help you guys can give me would be extremely appreciated!!!

Thanks so much!!!
Brandon

sh0gunshin

sounds like the cat. take the car and drive it for a bit. then look under near the o2 sensor. if the cat is glowing red, it's probably clogged and its time for a replacement

RX8Soldier

iTrader: (24)

This is one of those problems where many different possibilities are an issue.

The best thing to do is to VISUALLY inspect your plugs, coils and cat. If any of them are fouled, that's where you start.

RX8Soldier

iTrader: (24)

Ok, don't start a new thread about the same issue in every forum!

I'm going to paste my answer here. I suggest you delete your other threads, as this one has the most activity

EDIT: FROM OTHER THREAD
This is one of those problems where many different possibilities are an issue.

The best thing to do is to VISUALLY inspect your plugs, coils and cat. If any of them are fouled, that's where you start.

georgemagana

Thats how you can check your cat. A midpipe is just a part of the exhaust system that you can use to replace the cat to gain more power and sound. They are also way cheaper than a new cat that the dealer will try to sell you

hiroyukiiwaasa

If the cat is glowing red, how do I fix it?

Pico

iTrader: (2)

^ Dealer. Depending on the yr and mileage of your 8 it could be covered under warranty.

If your out of warranty your looking at a $1600 bill. In this case go with a D/R mid pipe or a high flow cat and save a bunch of money.

I'd go with a mid pipe regardless

RX8Soldier

iTrader: (24)

alright, FULL-STOP!

how many miles are on your car?
The Catalytic Converter is covered under warranty for 8years/80k miles.
The engine is covered under warranty for 8years/100k miles (providing you kept up with maintenance, and have the receipts to prove it... Unless they don't ask lol)

read here

Also, I suggest you read these
FAQ’s https://www.rx8club.com/new-member-forum-197/rx-8-faq-please-read-before-posting-959/
New and Potential Owner’s, Start Here https://www.rx8club.com/new-member-forum-197/new-potential-owners-start-here-202454/
Congratulations, you got an 8 https://www.rx8club.com/new-member-forum-197/congratulations-you-got-8-a-202548/
New Owner FAQ’s https://www.rx8club.com/showthread.p...&highlight=FAQ

Also, make sure you read the “stickies” in each sub-forum

hiroyukiiwaasa

Big thanks to George Magana and everyone else! Please keep any other advice coming!

Pico

iTrader: (2)

Full Go---------------

Oh and 8yr 80k only apply for us in the states, he never stated where he was from.

RX8Soldier

iTrader: (24)

lol there were just too many questions. Hoping I'd get OP's attention

sh0gunshin

judging from his name he may be from japan

hiroyukiiwaasa

My cars got 80,000 KMS on it year 2005 and Im from Canada

8upbad

iTrader: (3)

When the cat dies it chokes the flow of exhaust. If yours is dying slowly then it would make sense to me that the flow would get bad at a high rpm. This is a somewhat common problem with our cars. If you take the cat off you can inspect it easily from the inlet.

Bladecutter

Everything you have described that is wrong with your car are the symptoms of a failed catalytic converter.

How many more people have to tell you this before you understand, and have someone inspect your converter for you?

BC.

RX8Soldier

iTrader: (24)

OP, where in Canada are you located?
If you're around me, I'll check your cat, and any other issues you have going on with your car.

shadycrew31

iTrader: (6)

Theres a few things you can look for with a bad cat. go around for an easy drive (under 4k) around the block. have a look at your cat if its glowing red you know the things shot. you can pull the pipe and have a look down at the cat for visible damage, can't guarantee that you would see anything,but its free soooo yea.

Your 02 sensor might be going out, partsgroup.com has a used one (under 10k miles) I think give them a call and ask em how much it would cost.

As far as everything else goes you are on the right track, make sure you save the receipts for any maintenance parts you pickup so you can present them to the stealership.

yiksing

Ask a question, never bother to read or carry out suggestion, wtf....

Noobs used to be less noobier in the old days........

yiksing

Multiple thread on same post gg

hiroyukiiwaasa

Thanks for the help but Im from Lethbridge Alberta Wish there was someone like you around here...

RX8Soldier

iTrader: (24)

ok, what have you done to diagnose the issue?
Have you checked: (click the links for diy's)
Coils https://www.rx8club.com/series-i-do-yourself-forum-73/diy-mazda-ignition-coils-pics-178515/
Plugs https://www.rx8club.com/series-i-do-yourself-forum-73/diy-spark-plug-change-31872/
Cat https://www.rx8club.com/series-i-do-yourself-forum-73/diy-gutting-out-your-catalytic-converter-108878/

Razz1

You need a new rear O2 sensor or possibility of a new fuel pump.

hiroyukiiwaasa

Thanks for the help!! Okay I understand that the problem could be my cat, and the DIY shows me how to take it off, but how would I be able to tell if the cat is bad? Is the only way to tell is that it should be glowing red after a long drive?

FungsterRacing

iTrader: (4)

I love your approach to this!