wcs

iTrader: (2)

White RX8 (the white part is important b/c we know they are the fastest)
2005 MT with 64,000 km's

Plugs and Coils are new-ish (enough that I highly doubt they are an issue)

I have been running with the RP High flow for about the last 20,000 + KM's, e-test was performed while the RP high flow cat was installed.

Original Catalytic has been re-installed after failing e-test.

Existing mods
- RB Ram Air and Cold Air Intake
- TB coolant bypass
- Under drive pulleys
- Nitrous
- Cobb AP currently uninstalled

Special Note: Original Cat was used during the initial nitrous install. RP high flow cat was installed to save oem cat from failure (may have been too late). Rear O2 sensor maybe damaged from heat.

This is somewhat of a preemptive post as I am currently away and will only have few days to work on the car when I return before my plate sticker expires (end of April)

The last time I was home I went for my emissions test and failed. That same week I experienced other unrelated emission problems .. thread here:
https://www.rx8club.com/series-i-trouble-shooting-95/p0335-eccentric-shaft-position-sensor-circuit-problem-car-will-not-idle-194505/#post3509988

Before I left I was able to re-install the OEM Cat and reset all the goodies then uninstall my Cobb AP. Tried to get a few drive cycles in before I left over sea's -- all seemed good.

Ask the wife to take the car for a few my drives and all had been well until today. Check engine light is on. Now I have no way of knowing what the cell is as I am not at home but I would bet its a P2270 Rear HO2S signal stuck lean ON 2 HO2S ´ (See DTC P2270 ).
I would always get this cell right away when I had the RP high flow cat installed and I didn't have an MM map loaded which hid that cell.

So I guess in the effort to get this resolved ASAP when I return should I:
- Replace the rear O2 sensor which maybe damage (see crappy pic)
- replace OEM Cat.
- Both
- Other suggestion?

Thanks

Crappy pic of Rear 02 ...


Notice the silhouette, sensor casing is bent or melted


Just a pic


My failed emission test if anyone knows how to read it.

MysterLo

Just got my 2005 6MT Brilliant Black (The sexiest colour for the 8) with just over 60000km emissions tested yesterday. Completely stock.
Look at your results compared to stock...

wcs

iTrader: (2)

^^^ Holy CRAP!
Right so I haven't gotten a second test done since I put the OEM Cat back on, but I would bet that it isn't going to be as good as that.
Thanks MysterLo

I'm thinking replace the Rear O2 sensor, go get tested for 30 dollars if I still fail then I will go for the new OEM Cat (or maybe a used Cat?????)

Could low compression cause an emission test failure? Anyone? <shrug>

rotarygreg

so was there a cat on your car when you did the etest with the results you posted wcs? looking a the numbers, i would say no. usually, HC and NOx are sort of like a teeter tawter. if one is high the other is low. HC, means rich, and richs means cool. NOx means its burning stupid hot and thus lean. the only way i would say you could get those numbers is that you A) dont have a cat or B) your cat is totally screwed. I read your fist post a few times but its not totally clear whether you tested the car with or without the cat, although it is on now....

also, the rear O2 will not effect how the car runs. the rear O2 is simply there to monitor the cat and tell the computer its working the way it should and turn the check engine light on when its not. it doesnt effect how the car runs.

wcs

iTrader: (2)

^^^
RP High flow cat was installed during the e-test

Neo

Damn!!
I remember when I attempted to do an emissions test "legitimately" lol
The car is 16yrs old and I think she's only seen the inside of an emissions place twice in her life. The first when she was completely stock. She barely passed the test.
The 2nd time I attempted it, I had a "hi flow" cat as well. The paper looks very similar to the one you got Scotty! lol
Since then I've been getting emissions paper by other means...

I think it's time to locate a few friends who are able to help you with emissions...

wcs

iTrader: (2)

@ rotarygreg
Understanding that the rear O2 sensor only monitors the exhaust condition I would only be eliminating the check engine light.
So is it possible that the rear O2 sensor is faulty and sending a bad signal and the OEM cat could be fine?
Remember I have no way to confirm this right now. I'm curious because I'm going to order parts and make sure they are available for me when I return.
Do you know of cases of faulty O2 sensors?

wcs

iTrader: (2)

@ Neo
Have your people contact my people and I will buy the lunch and ...eerr Soda...

qtwre

iTrader: (1)

You're welcome to borrow the cat off my car for the test. Not that I know if mine is perfect, but I had a midpipe on for a year so the cat only has 2 years of use.

rotarygreg

that is possible. How long did you use the stock cat when you had nitrous? how hard did you drive the car in that state? I mean, i know you'd be on it good, but were you doing it at the track for 3 hours at time, or like a little burn on the street and shut off the nitrous and take it easy? the rx8s stock cat is a gorgeous peice of emission test passing metal. these cars run so insanely rich and some how that gigantic cat manages to clean up the mess after the fact. did you look at the cat before you reinstalled it? is any of the honeycomb broken away? any spots look melted? does it rattle if you shake it (when it was off the car)? If no, its likely okay.

Snrub

There are a couple of shortcut options:
1. Are you planning on selling the car? If not, you can just aim for a conditional pass. They make you spend up to $450 I believe. Two tests, plus a diagnostics gets leaves little room for actual changes to your car, so you probably won't have to do anything.
2. You can try running a significant portion of alcohol in your tank, just for the test. eg. Run the tank really low, hit the local pharmacy add alcohol, do the test, immediately hit the gas station and fill up.

touring8

would pre-mix cause these poor readings?

Corentco

Just had the same problem with my 2005 WWP.

Curb idle passed both HC & NO, but HC ppm were at 166 at 2503 rpm. I tried to lean out the map with MazdaManiac AP provided tunes....but of course NO ppm failed due to the changes (running lean) and HC dropped to only 111 ppm (still not hitting the 66ppm required). The emissions tech a KVR in Ottawa said that these cars (RX-8's) never pass and it's a common issue due to the crappy coils mazda use as stockers.

I've ordered up an ignition system from Charles (BHR) and will give it third try with new plugs/wires and the Yukon coils. Next to that I guess I'm in a market for a factory cat (died 15K ago).

Any other suggestions?

TheWulf

iTrader: (4)

^ You got PM.

Also check out the Ottawa boards at http://www.ottawamazda.ca

nate340

did you try to pass a e test without a cat? cause if so thats the most amusing thing iv herd all yr.

btw just passed mine yesterday evening, thanks so much to a member on this forum for loaning me his cat passed with flying colours.

why arent you guys going to mazda and getting free cats if your under 128 000km ?

Corentco

I'm runing a high flo cat.....I would expect to fail with a test pipe. Look at my sig.

wcs

iTrader: (2)

Thanks Eric,
I will keep this in mind.
Thinking about it .... it maybe worth our time to just get that CAT installed and go get a test done for 30 dollars to see if it is indeed any good anyway.

wcs

iTrader: (2)

- OEM Cat was on for about 20,000 + km's of nitrous (10 tanks)
- Used it at the drag track a few times, on the Dyno for a total of 3 passes in 4 fourth gear up to 9000 rpm, I would never use nitrous on public roads, the rest was used on my own personal road course - hard
- Inspection of the CAT showed no visible signs of cracking, melting or rattling. However the mechanic that initial took the oem cat off said the Rear O2 sensor was basically fused into the bung hole. I think they were lazy just wanted to use the acetylene torch on it.

1. No not planning on selling the car. Wow I didn't know you could do this. Great info... Could I still do this to buy some extra time for myself?

2. Hard core. Would the 70% stuff do? Err yes ma'am I would like 3 cases of your Isopropyhl Alcohol.

- Ummmmm yes sir Mazda shop manager sir that is a Zex nitrous nozzle in a Black Halo throttle body spacer. (I guess I could start removing more parts. Maybe worth it if I go that route of trying to get a free cat from mazda)

nate340

that makes a lot more sense.

i went into a mazda dealer at 126 000km for a new cat since it was obvious mine was gone could smell it and hear it rattling around, they said i had to replace the coils/plugs and rear o2 sensor since the car was cutting out randomly. it actually was the fuel pump causing the issues. but by the time it was all fixed i was at 132 000km and they told me to get lost since i was out of the emissions warranty period.

wcs

iTrader: (2)

LOL
Well I just ordered a BHR fuel pump and new plugs.
I also have a set of brand new BHR coils sitting on my work bench.

Snrub

1. You can have as many conditional passes as you like, as long as you don't sell the car. You might want to let the shop know that you're aiming for a conditional pass. If they play ball they won't try to be creative to get you to spend all $450, and will justify why you can only spend ~$150 (ie. other parts like OEM cats too expensive, whereas aftermarket may not be). My car had two conditional passes on my TII.

2. I've never actually done this, but others have and it stands to reason it would work. I think you want 100% alcohol, but have some gas in your tank so you're running a high percentage, but not 100% alcohol. Obviously there's some potential to damage various parts of your car. #1 would be my preferred option.

wcs

iTrader: (2)

@Snub dude thanks ...
I am going to approach them this way when I get home.
I have several backup plans and will keep the thread updated.

wcs

iTrader: (2)

Soooooo....
Got home yesterday ... had the emissions test today.
Cleared the cel again before the test .. this time it was a
- P0138 Rear HO2S circuit high voltage ON 2 HO2S
- U1900 which is some bus comm IO error

So now I'm thinking the rear O2 sensor is hosed.

Well shortly into the emissions test (they let me stay in the car) the engine light went off again. This time it was a P2270 Rear HO2S signal stuck lean ON 2 HO2S

Car passed no problem I will post the emission test later.
I've purchased a new Rear O2 sensor ..... I want to see if this solves the cel.
If it doesn't I guess I have issues elsewhere, as the car is basically stock right now.

Will post after a few drive cycles with the new Rear O2 sensor.

Thanks for all your help guys

01Racing

If your running pre-mix you will mess up every sensor in the exhaust system and gum up your fuel injectors as well. None of those components were designed to have oil run through them. The factory oil metering allows a precise amount of oil that will be burned in combustion. Any additional oil will get through to the sensors.

Chad D.

iTrader: (19)

/\wtf? 2 cycle burns much better than the dirty 4cycle dyno in the crankcase.