ok first i should let you know this isn't an O2 sim but another way to get the same effect. some guys want to take out or gut a cat out and a couple exhaust systems come complete with a race/cat-delete pipe, i have the exoticspeed headers all the way back. Ive read a couple of threads on here about O2 sims and how they don't work and if the do your lucky. well i found a way around it where you don't have to cut any wires. i don't know if this is new or not but i haven't seen it on here.

well what i did was this:

step 1- went to my local auto parts store

step 2- got a HELP! part #42009. this is a spark plug non-fouler.

step 3- open the package....ill stop with the steps

the idea is to block most of the exhaust from the O2 sensor. the non-fouler needs to be drilled out for the O2 sensor to fit. i used a 31/64th inch drill bit but half inch might work too. the spark plug non-fouler is threaded on the inside for the O2 sensor and the end is threaded on the outside to fit in the pipe. you drill it out...thread the O2 sensor in tight...then thread the whole assembly in where the O2 sensor would in the race/cat-delete pipe. then reset your pcm and that should be it.

my friend has a CEL code reader so after a couple days of driving and the car going through many drive/catalyst cycles we checked to see if there were any codes pending....it said catalyst ok and i haven't had a CEL yet and i don't think i will. but if i do and if anyone else tries this then just add another non-fouler to decrease the amount of exhaust gases the O2 sensor reads. i have one on and my O2 sensor sticks out about an inch more than it does normally but has plenty of room.

interesting, i think im going to have to try this, im tired of seeing my cel on

i tried something similar and got a code saying "o2 sensor slow response"...i guess your just lucky...

well the O2 sensor needs to read some but not all the exhaust gases to register. if you drill out the spark plug non-fouler too much then you will get the CEL..same as if you dont drill enough the sensor wont read any of the exhaust gases. maybe i got lucky when i use a 31/64th inch bit...maybe thats the magic size. if it doesnt work right off the bat for you like it did for me then play with it...get it to work. i mean the part only costs like $5...alot less then any O2 sim.

Good info, there has been people here talking about using plug foulers, but from what i remember, they didnt drill it. Sometimes it takes a few days for a CEL to come one after gutting the cat... id be interested in seeing if youre still not throwing codes after a week or so.

Keep us updated!

ive doen this before... you need 2 of them and it works like a charm

it can take several drive cycles to register a malfunctioning cat.

Just get the cobb accessport and delete the cat CEL so it doesn't show up, instead of hardware trickery.

I'm plaaning on gettin AP as soon as my Stimulous check comes in, but for now, this may get me by

why buy the AP for $600 when you can buy that part for $5. plus you dont have to clear your codes every day.

ap deletes the code for good...

Yeah, AP can disable CEL codes, and allow diff fuel and timing maps... So its not just a O2 delete, its a tuning tool.

I think I'll try the 10$ method, instead of the 600$

I have yet to see a trick method that can fool the rx-8 pcm

yea, but if there is a slight chance it might ( as in these few people who it has worked for) I am still willing to give it a shot.

i just might have to check that AP out! but this little trick is working for me. every time we read if any codes are pending it says catalyst ok.

Question: when the pcm throws a CEL for the cat, does it run in open loop only?

no, it still should be making adjustments as per the primary wideband o2 sensor... the secondary is there to make sure the cat is doing its job...

why buy the AP for $600 when you can buy that part for $5.

because then you also get fuel maps that will actually let your $1000 exhaust make power?

no, it still should be making adjustments as per the primary wideband o2 sensor... the secondary is there to make sure the cat is doing its job...

I don't disagree with you, but I wondered if anyone had checked it with a scan tool to be sure. I know older vehicles would sometimes go into open loop for any code that lit the CEL.

new PCM's can tell if its puttin the motor at risk, if its not, then it wont (shouldnt) go into open loop

yea, but if there is a slight chance it might ( as in these few people who it has worked for) I am still willing to give it a shot.

get back to us..

we love fail!!!! after the one you are going to try. i can give # 2..

beers :beer:

I spend more than 10$ on a drink at the bar,
its worth a shot to me, I am going to try it today

Good luck, report back in about a week of normal driving and let us know if the CEL ever came on

well its been a couple weeks and a couple hundred miles or so and still my cat code is good.

thats very promising.... thanks for the update!

well its been a couple weeks and a couple hundred miles or so and still my cat code is good.

what year? m/t or auto? hw many miles?

05 6mt 23000 miles

got pics? ;) I might try this when I put on the gutted cat..

ill put up pics when i put my pulleys on sat

photos?

beers :beer:

its on, so far 2 days no cel.
I drive the shit out of it. lol
I will keep this thread up dated after another week or so.

yeah im driving mine pretty hard too.

and here is a pic of the part to get

yeah im driving mine pretty hard too.

and here is a pic of the part to get

you are one of the lucky ones.

seems to work about 50 / 50.

beers :beer:

With one the cell comes on shortly after 312 miles. ;)

Tested on two different manual '04's

2 it comes on in 30 - 50 miles.

still great after second fill up (so far 298mi)
on mine

yeah ive drove two tanks on mine so thats 400-500 miles. like i said maybe its the size you dill it out to fit the O2 sensor.....maybe 31/64th is the key...at least for me lol

this particular idea looks to be popular elsewhere too...

http://forums.nasioc.com/forums/showthread.php?t=424666&page=2

sheit, I would try it but my 8 is down. what was interesting when I replace my cat with one of rx7stores resonated jump offs I didn't get a cel for almost 600 miles....

now its a whole different story.

This works for every vehicle I have tried it on...I have ran it on my denali for years now. I tried it on my 04 AT with midpipe and it did not work at ALL...code would reappear within 50 miles. Tried it for months. I used one, I used 2, started with a small hole, then went bigger...nothing worked.

still great at 320 mi

320 miles with what driving style?

mixed, stop and go traffic, with a good amount of beating/ highway driving red lining.

same with me and i just ran an autocross race last sunday with 5 runs...still no CEL

How long until the CEL comes on is dependent of gasoline quality as well (how cleanly it burns) I was able to drive 400mi on 76 premium (with multiple redlines) before the light came on ~ my girlfriend borrowed the car and put in $15 of premium from arco (:banghead: ) and the light came on within 40 miles of regular driving. I noticed similar observations with a gutted cat as well...

The parameters to set a CEL are in the service manuals, has nothing to do with distance, time or gas quality.

It takes a certain number of 'drive cycles' to set a 'pending' code, each one a specific time of cruising, a certain time at 'fully warmed up' etc.

Then a specific number of these drive cycles are required to set the light to on. After another number of cycles the light will turn off, to make room for new codes, but the code is still set in memory.

The ECU can check the O2 sensor if it wants, sends a check of rich/lean pulses and looks for corresponding signal moves. This is why the electrical sims all fail to fool it.

S

well my car has had over 40 "drive cycles"
and been ran on 89 oct. and then filled up half (back to top) with 91, and then all 91.
STILL no cel, at 456 mi.
I am pretty confident this worked for me, but if it happens to come on I will post up.



I recomend coughing up the WHOLE 10$!!!! omg.
and try this mod, if it doesnt work, shux your out 2 packs of smokes.
if it does, you have no more cel.!!!

:cheers:

Are you guys running full blown midpipes, or just ineffective cats that were triggering the code because they went bad?

well im running the exotic speed exhaust with the midpipe

I have no cat what so ever, took it to a local shop and had a guy weld in a straight pipe with a bung in it.

Just to add to the list of things that don't get rid of the cel rear cat low, I added two o2 bungs to my cat less pipe and still have cell. :banghead:

why do you need two?

i read or heard somewhere that adding one or two to the existing would stop the cel, but it didn't.

did you drill out the hole before installing this?

There is nothing to drill out a bung is what your 02 sensor screws into, i welded 2 on top of the existing to back the sensor out of the pipe

than thats your problem.. if you used a spark pluf de-fouler, not only does it pull the o2 out of the direct stream, it limts the amount of air in it... except in our case it needs to be drilled out some.. worked so far for 2 people here

still working great for me at 500+ mi

same for me700+ miles...and i was pm'd to make one for $15...ill do it and if any one else want one let me know.

same for me700+ miles...and i was pm'd to make one for $15...ill do it and if any one else want one let me know.

where you located?

Im currently using one thats MEANT for this purpose (off road use) and...
so far.................

... its not working, lol.

The peice is about the size of 2 of those HELP ones and the hole is about four tenths of an inch or so.... cant remmeber.

im trying to find a pic of it so i can post it....
not sure if I would need something longer, shorter, bigger hole, or smaller.i got the Turboxs exhaust, no cat, greddy turbo about 15k on the rebuilt motor, about 50k total i think...

Wait, I think I remember it working for me for about 970 miles before the CEL came on.

you know, its been so long that ive had it on the car that i dont remember the actual size...

http://img.auctiva.com/imgdata/0/9/0/2/3/8/webimg/117633440_o.jpg

this looks a lot like it, but i remember it being longer... cant remember, let me go to my garage and look real quick...

yeah, mine are twice that long

I ran this technique on my KA24DE-T S14 for some time with no problems. 1 HELP bung with THREADED nut welded to it. I was running emanage blue with OBD1 Engine Management, not OBD2. I had heard it is possible if too much exhaust gas is reaching the O2 Sensor some wire mesh can be installed inside the bung before installing the O2 Sensor. If you are creative this is feasable, dont know about steel wool but I think it would evaporate, LOL.
118590

Wait, I think I remember it working for me for about 970 miles before the CEL came on.

I am now at 1200mi. still no cel.
w00t

still no cel

miles?

I losts track but over 1700 now.

I'm suprised more members haven't tried this mod. Don't have a midpipe on my 8 yet but I have used this mod on Hondas since 1999.

The Honda PCM and the Mazda PCM are two very different beasts.

The Honda PCM and the Mazda PCM are two very different beasts.

I know...never had to tap the brake 20 times then turn the wheel to reset the e-shaft in a civic.

I know...never had to tap the brake 20 times then turn the wheel to reset the e-shaft in a civic.


and you dont have to turn the wheel to do that to a rx8..

beers :beer:

I know...never had to tap the brake 20 times then turn the wheel to reset the e-shaft in a civic.

Your civic has an e-shaft? ;)

the point is.
this cost 10$.
if it doesnt work for you, oh well, your out 3 gallons of gas.
if it does.
great.

Your civic has an e-shaft? ;)
lolwtfbbq?

yeah im well over 2000 miles now and im good......ive had 2 orders for me to make these at $15 each so if anyone else would like one let me know.

i just got mine....ill put it in sometime this week and ill keep this thread updated....

Guys who have SUCCESSFULLY installed these, please explain any mods to Help part along with pictures of location installed. This is critical for the success of everyone prospective of this modification.

Also, were the hondas OBD1 or OBD2 or both?

my car is all stock w/ hks hi power exhaust and a custom straight pipe, (o2 bung welded right into the middle of the pipe)

Very interesting.... I will try this.

I am now at 1200mi. still no cel.
w00t

I losts track but over 1700 now.

yeah im well over 2000 miles now and im good......ive had 2 orders for me to make these at $15 each so if anyone else would like one let me know.

You sure put on alot of miles in less than two weeks. :Eyecrazy:

did not work at all for me..... the cel came on quicker than without it.... i have a borla exhaust with a guttet oem cat

....

still working for me at 2k+ mi

ive had it on for 200 miles or so and have no cel.....my cel usally comes on after 3 drive cycles before......its been like 20 drives and so far so good....

Im going to go buy the help part and get my cat removed, if it fails I will have you make me one..... shouldnt be that hard to do, my bet is, people are probably drilling the hole too big

still working.......

Glad to hear it's still working... Now will someone make something to cover up the smell? Maybe a Febreze injection nozzle in the tail pipe :lol:

I just installed a midpipe. Used a single fitting drilled as described in the first post. It took exactly 8.9 miles (2 cycles) of city driving for 3 codes to return and set the CEL.

The codes represent "oxygen sensor stuck lean" and "oxygen sensor slow response" so perhaps it is not getting quite enough "dirty" exhaust flow. I will remove the sensor and open the hole in the fitting up just a bit and continue to try it again.

still working......my 8 is my daily driver as well....

great for you, sucks for the rest of us.

I drilled mine out to a little over half an inch and tried it again. Took about 11 miles of city driving to light the CEL and give 2 codes this time, both for "slow response" again.

i think the hole has to be just right so it gets just a little of the "smog"...if its too small youll get the slow response code...

I think as more people try this and we get more results, it will be found that at best, it could be said this works "for some of the rx8s with midpipes, but not for others" and at worst it works "for a few of the rx8s with midpipes, but not for most".

So I tried a 9/16 hole in my fitting and still got the codes. So that means on my car, I have tried fittings with holes of 31/64, 1/2, and 9/16, and NONE of them worked for more than 10 miles before giving "slow response" codes.

So I figured I need more "dirty" air getting to the sensor. However, i cannot drill much more out of my fitting, because I will be getting into the outside threads if I try.

I tried threading the sensor into the bung on the midpipe with no fitting in between, but I did put 2 extra crush washers there to space it out from the pipe about 3/16". I was able to put about 100 miles on it (3 or 4 drive cycles) before the codes returned, and this time it was "inefficient catalyst"...which means TOO MUCH dirty air is getting to the sensor now. I may try it again with another washer, if the sensor will still thread in. Or I may weld on an additional sensor bung, over the existing one in the pipe and go from there.

my car is completely stock other than the cat and resonator being removed with 2.5" pipe in its place, put the help part in, and kept it at the same angle as it was in the cat, no code after 70 miles..... car sounds like a rotary now lol.... I used a 1/2" drill bit and it looks like you can barely see a gap in between the sensor and the non-fouler, but I think that is why it works so well....

main reason I did mine is the cat was clogged, and was losing lots of power.... car feels great now, and drives perfect..... just a little raspy with the stock muffler.... may change that later

car is a 2004 in case that makes a difference

Did you make this pipe yourself? If so, got any details and/or pics?

tried this in my exotic speed exhasut with midpipe, nothing worked, still got the cel

still trying variations without luck...

still working......ive been on a roadtrip totaling over 1,500 miles...so i guess im good to go...btw i had the op make me one and send it to me....

I had the local exhaust wiz do it, he works inside a muffler bros locally, not giving out the location so he doesnt get into any trouble.... but he does really good work.... the pipe just has that slight bend like the cat does, and the 02 sensor is mounted just below the middle of the side of the pipe, exactly how the 02 sensor went into the cat.... I have a spare non fouler if anyone wants it, it looks just like the one I installed....just pay the shipping +$2 for the cost of the part I will get under the car tonight and take a picture of my mid-pipe to show you guys how it looks.....

If your cat was clogged, you probably could just have gutted it, no? Then it would still look like a cat (for visual inspections). What happens to the resonator -- does it get destroyed too when gutting a cat?

lol sure I could have just gutted... but I dropped the weight by quite a bit removing the cat and resonator.... the only thing the cops look for around here is to see that you have a muffler on the car.... when I had a srt-4 it was hard to explain to the cops that I didnt have a muffler stock...

i tried something similar and got a code saying "o2 sensor slow response"...i guess your just lucky...

I had this same problem too, but it now seems to be fixed. I am using both non-foulders with the first one drilled out with a half inch drill bit.

I got this code twice under very hard driving. I did a steam clean on my engine and reset my long term fuel trims. I'm sure resetting the long term fuel trims did it. I'll keep everyone posted on if it comes back or not.

Here is a pic of it installed on my car.

ah i spoke too soon, it came back on the way home... will try the 1 bung this weekend and let you know.

I am still experimenting without success as well. I do seem to be getting closer, however.

I am still experimenting without success as well. I do seem to be getting closer, however.

close,

yet so far, kinda pisses you off! odd how the 04s vary so much.

good luck. and thanks for the notes on the mt to at swap.:)

beers :beer:

The parameters to set a CEL are in the service manuals, has nothing to do with distance, time or gas quality.

It takes a certain number of 'drive cycles' to set a 'pending' code, each one a specific time of cruising, a certain time at 'fully warmed up' etc.

Then a specific number of these drive cycles are required to set the light to on. After another number of cycles the light will turn off, to make room for new codes, but the code is still set in memory.

The ECU can check the O2 sensor if it wants, sends a check of rich/lean pulses and looks for corresponding signal moves. This is why the electrical sims all fail to fool it.

S

I guess I was thinking too much on a cause - effect basis. Very informing though, thanks for the reply!

Still I have no CEL after over 5,000mi with no bung. Anyone have any insight to this?

close,

yet so far, kinda pisses you off! odd how the 04s vary so much.

good luck. and thanks for the notes on the mt to at swap.:)

beers :beer:

Swoope do you mean AT to MT swap?

Swoope do you mean AT to MT swap?

yep,

that was a great read, and a whole lot of work. glad i never would have to do it. :lol2:

beers :beer:

k noob question... how do you reset your pcm? im guessing just un-hook your battery?

sticky at the top of the tech section...

awesome. thanks

still more combinations of hole diameters and spacer thicknesses have not worked for me. After about 1000 miles of experimenting and never going more than 100 miles before a code returned, I got fed up and put the stock cat back on. The main reason i wanted to run a MP was to reduce the cabin heat, which the MP does considerably (when heat wrapped).

But, putting the stock cat back on gets rid of those pesky codes, and also gets rid of the harsh rasp sound at 3800-4300rpm (when used with the stock catback).

In my opinion there is not a lot of power difference...maybe 10hp at most.

still more combinations of hole diameters and spacer thicknesses have not worked for me. After about 1000 miles of experimenting and never going more than 100 miles before a code returned, I got fed up and put the stock cat back on. The main reason i wanted to run a MP was to reduce the cabin heat, which the MP does considerably (when heat wrapped).

But, putting the stock cat back on gets rid of those pesky codes, and also gets rid of the harsh rasp sound at 3800-4300rpm (when used with the stock catback).

In my opinion there is not a lot of power difference...maybe 10hp at most.

weld yourself another resonator, get a cobb AP, good to go :)

So you're saying I should spend close to a grand to get 10-15hp?

So you're saying I should spend close to a grand to get 10-15hp?

nope... but a min of $700(for AP and punching out cat) up to $1Kish (if you buy a pipe) is worth it for other reasons.

its never a bad thing to have control over the fan turn on temps, although i dont think you'd have any problems with the weather back home. Control over the OMP is nice as well, although it MAY still not be adequate for some(and still use premix)

but losing the cat and the extra fuel through the torque band is very very nice, i could care less about the 10hp it makes. the fuel savings will pay for it the AP + the cost of your 'catless' solution in a less than a year.......

of course, i am kinda biased as i see the AP as the best option availible for the forseable future for management, and that is a mandatory thing for me to have come a couple months when i am home again ;)

nope... but a min of $700(for AP and punching out cat) up to $1Kish (if you buy a pipe) is worth it for other reasons.

its never a bad thing to have control over the fan turn on temps, although i dont think you'd have any problems with the weather back home. Control over the OMP is nice as well, although it MAY still not be adequate for some(and still use premix)

but losing the cat and the extra fuel through the torque band is very very nice, i could care less about the 10hp it makes. the fuel savings will pay for it the AP + the cost of your 'catless' solution in a less than a year.......

of course, i am kinda biased as i see the AP as the best option availible for the forseable future for management, and that is a mandatory thing for me to have come a couple months when i am home again ;)

That style of management, at least. For now, you are right.

Does this still work out for you?

Update Please.

finally the CEL came on....took a while and put alot of miles on it till it came on. sorry its not a permanent fix! it came on a week ago.

Thread revival!


I tried this mod with my OBX mid-pipe - 1/2" hole with the O2 threaded into it, then threaded the drilled non-fouler into the undrilled non-fouler, and finally into the test pipe. It didn't take long for the CEL to pop up. There were 4 codes, two of them were that the sensor was responding slowly, and the other two were that the O2 sensor was detecting a lean mix. I haven't tried removing the undrilled non-fouler, since I haven't had time to remove the entire mid-pipe, plus I have a feeling that it wouldn't help. :(