CEL for emissions

my CEL just came back on, after about 500 miles, i know that is where the computer begins to gather positive data from the emissions system, however, i do not have a cat, so i made myself a rear o2 bypass/simulator using the DIY instructions on tuners... well, obviously, that didn't work... and i need a state inspection (OBDII)... any ideas? (i dont want to buy a cat) heard of this little trick of using "spark plug non fouler" and thread the o2 sencor into that...
http://www.scoobymods.com/forums/showthread.php?t=5468
any info from anyone will help dearly!

What code do you have? I have no cat either and have never came up with an emissions CEL. I've heard of the resistor from radio shack you can use to bypass it, but never tried it myself (No emissions here).

P0136... something about the first bank 2nd sencor o2... dont really know what to do about that...

Hmmm I take it that DIY from tuners was the resistor mod? That sparkplug non fouler might be worth looking into. It looks pretty cheap, so if it doesn't fix the problem, you aren't out a whole lot of cash.

I've heard of that foil trick, putting it around the o2 sensor. But I'm not really sure how that would work out.

You said after 500 miles the CEL came back on. Any chance you could clear the codes right before taking it to get the emissions test done on it?

yea i say you just clear it on the way to the shop

wait a minute if you have no cat you're going to fail emmisions anyways?aren't you?

wait a minute if you have no cat you're going to fail emmisions anyways?aren't you?

If you have to do a sniffer. I know some states don't do a sniffer but do require a visual inspection. (you can also always swap out your non cat pipe for the stocker and get it inspected)


I don't know why you would throw a code though. My GST had straight pipes on it and never threw a code at all.

Every once in awhile ill get that P0420 catalyst efficiency below threshold. But have never had the o2 sensor bank 2 code.

When I had my front o2 sensor unplugged, I got that bank 1 code. It's possible that the sensor might just be bad. Although I'd hate to buy one just to turn the CEL off since they really serve no purpose anyway.

Also I've heard through the rumor mill that these cars will pass emissions without a cat anyway. Keep in mind this is just what I've heard and have no idea if its true or not. Correct me if I'm wrong, but if you fail an emissions test you aren't charged for the test. Aren't you only charged if you pass, or if they fix the problem for you?

Every once in awhile ill get that P0420 catalyst efficiency below threshold. But have never had the o2 sensor bank 2 code.

When I had my front o2 sensor unplugged, I got that bank 1 code. It's possible that the sensor might just be bad. Although I'd hate to buy one just to turn the CEL off since they really serve no purpose anyway.

Also I've heard through the rumor mill that these cars will pass emissions without a cat anyway. Keep in mind this is just what I've heard and have no idea if its true or not. Correct me if I'm wrong, but if you fail an emissions test you aren't charged for the test. Aren't you only charged if you pass, or if they fix the problem for you?
i pass the sniffer with Flying colors w/o a cat, but i fail the OBDII test which is required ON TOP of the Sniffer and safty here... i just need that code to be fixed because if i clear it, it will say "system not ready" for the OBDII test, and again, i will FAIL... i made bypass simulator, so the stock o2 isnt even in the car, i have a wideband where the stocker was... but the code that is popping up is for the Rear o2 sencor Right? it kinda freaked me out when it was saying shit about bank 1 sencor 2 or something on the reader @ advanced autoparts... any tips from anyone?

These cars stock may be able to pass the sniffer without a cat, but look at what you guys got done to them.

I cleared my CEL on the way to the emmissions place... and I have a cat and a rear O2. Had some problems with the rear O2 not working right and kept getting CELs. Actually threw the code again on the way home, like a mile from the place.

I heard putting a Silencer on the muffler helps in the sniffer test. Weird. IDK how true that it.

I dont have a cat, followed the resister mod from tuners for the most part and it took care of my cel completely.

I dont have a cat, followed the resister mod from tuners for the most part and it took care of my cel completely.
how did you do it? that is my best option, and i did it...

-1-Megaohm Restrictors (½ watt 5%)
-4-50 Ohm Wire wound Restrictors (10 Watts, 10%)
-1-1.0uF Metalized –film Capacitor (radical leads 250WVDC max)

but for some reason, i still have the code!

If you live in Cali, you will not pass the sniffer without a cat.

The way I did it does not allow you to remove the o2 sensor, but it keeps it from throwing a cel for no cat.

I tried to totally eliminate the o2 sensor but I still would get a cel every now and then and the 50ohm resisters got incredibly hot that it was starting to look like a fire hazard. I only used 3 but they would get to around 200F in about 15 minutes. So Heres what I did, I used a 1Mohm resister and 1uf capacitor. Hooked the o2 back up like it was stock, then spliced into the o2 signal/ground wires. And soldered the resistors in between the wires. I used to get a cel every few weeks or so but it has been about 4-5 months since I have seen one for that.

Let me draw a pic so it will be more clear.
http://i189.photobucket.com/albums/z173/SilvrEclipse/Untitled.jpg?t=1189183087

is there a certain flow of electricity thorugh the 1Mohm resister and 1uf capacitor. if so, could i just have them backwords? hmm... i'll have to look into that tomorrow...

changin the conversation back to the problem im having... regardless of where i live (calif/NY/Florida/Mexico) i need the check engine soon light to shut off about not having a cat, perminately. not only does it anoy me, but it is keeping me from passing OBDII emissions. what can i do (*that works*) that will make the computer *THINK* i have a catalytic converter with out having a catalytic converter?

Are you trying to get rid of the second o2 altogether? As far as I know you cant eliminate the sensor completely.
I dont think it matters which way the resister and capacitor are.

As far as I know you cant eliminate the sensor completely.
I dont think it matters which way the resister and capacitor are.
oh Shit! well thats what i need to do, i followed the directions found http://www.dsmtuners.com/forums/showthread.php?t=221951 (Here)
and here is what i came up with:
http://img339.imageshack.us/img339/6319/dscf0001wq0.th.jpg (http://img339.imageshack.us/my.php?image=dscf0001wq0.jpg)

http://img76.imageshack.us/img76/2021/dscf0003vr7.th.jpg (http://img76.imageshack.us/my.php?image=dscf0003vr7.jpg)

http://img112.imageshack.us/img112/905/dscf0004aa4.th.jpg (http://img112.imageshack.us/my.php?image=dscf0004aa4.jpg)

had it on the car for about 3 weeks (dont drive the car that often) and the cel came on the other day... as explained earlier... WTF? any ideas on how to get the ECU to think my Rear o2 is their? i need to maybe ask kevin... or Brian... bet they would know... u think?

And that doesn't work? I would watch those resisters to make sure they aren't getting to hot. The problem I see is that that type of setup only gives the ecu a constant reading so the computer picks that up as an error bc the signal isin't changing. With the sensor connected the signal varies but the resister and capacitor slow the reading down so that the cel isin't triggered for no cat.

And that doesn't work? I would watch those resisters to make sure they aren't getting to hot. The problem I see is that that type of setup only gives the ecu a constant reading so the computer picks that up as an error bc the signal isin't changing. With the sensor connected the signal varies but the resister and capacitor slow the reading down so that the cel isin't triggered for no cat.

hmm... so u think i chould tee off the factory o2 from my one sencor hole in the exhaust? like... thread a tee into the hole, put wideband in one, and the factory in the other and still get good wideband readings? can i get a pic of what you did? so i can see what restrictors and capacitors you are talking about?

I wouldn't recommend T-ing off the sensor, the WB needs to be in the exhaust stream. There is a link on page 1 of how mine is set up. You might just need to weld another bung in your exhaust for the WB.

DSM ECUs don't really care what the rear O2 absolute voltage is, AFAIK. All the ECU is looking for is that the rear sensor signal is not cycling like the front one is. Back in the day many people had good success just tying the sensor up somewhere where it won't start a fire. This is where wrapping it in foil came from, to protect the car from the heat. The sensor will provide a low, flat voltage to the ECU. This is usually enough to keep it happy. The anti-foulers only limit the sensors exposure to the exhaust gas, to slow down the cycling. These have been reported to work pretty well for people on the EVO forums, worth a shot.

With more modern cars, the ECUs are a little smarter. They force the AFR to change at certain intervals to ensure the sensors respond as expected.

There are also ways to force the readiness tests to "pass," but this gets more complicated.

AFAIK??? so your telling me to take the sencor out of the pipe and to wrap it in foil? and that will take care of my cel? *i was hoping you would stop buy and drop some knowlege keven!*

The only way to find out if it will work on your car is to try it. ;)

point taken... ok! thanks buddy! how would you suggest I tie it up?

Zip tie that bitch up there

This is the wierdest thing I have ever heard of. I will have to give it a try.

will i have to drive another 500 miles to reset the cel? because it didnt turn off right away... i should know this, but you know... might as well ask to just make sure...

so you wired the sensor back up and wrapped it in foil? It will take a few days to go off.

will i have to drive another 500 miles to reset the cel? because it didnt turn off right away... i should know this, but you know... might as well ask to just make sure...


Did you try removing the battery leads for 10 seconds and reconnecting them? This should reset the computer.