Emissions with catless exhaust

[usmc.S4]

Did some searching, didn't find a solid answer. So how do you guys pass emissions without cats? Throw the stock DP's in?

[bigdo26]

I'm looking at having my stock main cats welded into my non-resonated mid-pipes (I have catless resonated mid-pipes normally) and just clamp those in & hook up O2's for emissions. Little bit of a pain, but not as bad as putting back in stock DP's.

Although I need a new O2 sensor first :) I think that is easiest if you have the parts

[usmc.S4]

So how would I do that? Cut my stock cats off and weld the right size pipe to the ends so I can clamp it to my exhaust?

[wbrunner23]

If you ask around, you may be able to find somebody local who can code out your rear O2 sensors.

I live in PA where to pass emmissions you just can have any CELs and need to set all but 2 monitors (I believe that went up to all but 1 monitor for 2002+my or something).

I found a guy on here, who I won't name, that was able to code out my rear O2s so that my cat monitors set immediately (I still have my main cats in, just gutted pre-cats, but plan to gut the main cats once I have a reason to take the car apart again...probably when I change my clutch in the next month or so). By gutting the main cats, in place of using test pipes, and leaving the rear O2s in the bungs, my exhaust will appear to have cats intact and O2s reading emmisions

[c0rrup]

In CT there is no visual inspection, I can pass emissions with no exhaust or downpipes as long as readiness codes pass.

[usmc.S4]

In CT there is no visual inspection, I can pass emissions with no exhaust or downpipes as long as readiness codes pass.

Good thing I'm from CT, I'm stationed in NC and Ive been exempt from emissions testing because I'm active duty. But I'm getting out soon and will require testing shortly after. So if I get my rear o2's coded out I'll be set? CT doesn't do the sniffer correct? Just the plug in?

[CELison]

make friends

[c0rrup]

Good thing I'm from CT, I'm stationed in NC and Ive been exempt from emissions testing because I'm active duty. But I'm getting out soon and will require testing shortly after. So if I get my rear o2's coded out I'll be set? CT doesn't do the sniffer correct? Just the plug in?

They slap in the cable, scan it, and you are on your way. They don't even start the car.

[Scotty@Advanced]

It's likely Your car won't pass a sniff test without cats. It depends on the testing method your state uses. In Texas AWD vehicles and diesels are exempt from emissions testing.

[MadProfessor]

NC just does a readiness test..They should not be using a sniffer or anything like that. Only via the OBDII port.

[usmc.S4]

NC just does a readiness test..They should not be using a sniffer or anything like that. Only via the OBDII port.

I'm stationed in NC, my car's registered in CT. Don't have to do emissions until I get out of the marines, which is in like 6 months. Just trying to get my car ready for back home so I'll pass. But the main question is, will coding out my rear o2's work?

[aysix]

I'm stationed in NC, my car's registered in CT. Don't have to do emissions until I get out of the marines, which is in like 6 months. Just trying to get my car ready for back home so I'll pass. But the main question is, will coding out my rear o2's work?

Yes. CT is awesome with emissions, get that "ish" coded out. Go there with your down pipes dragging on the ground and you are fine.

I can help you with the rear o2 jazz.

[///BlueS4]

So how would I do that? Cut my stock cats off and weld the right size pipe to the ends so I can clamp it to my exhaust?

I had my cats cut out and pipes welded in and the o2's pushed back a little further then stock placment. I also add a spark plug non-defouler and havent gotten any check engine lights no failed emissions either.

[Meow]

Lol @ emissions... so glad I am from Michigan, almost anything is street legal (for michigan law, still federally illegal)

[S4 00 2.7]

You guys don't know how good you have it!

[britishturbo]

All depends on where you live.

Where I live in PA there are no emissions testing. just mechanical testing.
Makes things very easy ;-)

If you just need your ecu tune tweaked to set things as ok I could help you out there.

[Dr. Funk]

Cant you just get defoulers and space the o2 sensor a bit off the exhaust??

[A62TURBO]

Thank God New York doesn't use the sniffer anymore, not that I would run without cats or SAI on public roads

[bigdo26]

In CT there is no visual inspection, I can pass emissions with no exhaust or downpipes as long as readiness codes pass.

I coded out my EGT's and rear O2's, so I don't have any CELs, but will readiness codes be OK? I read up a while back on those, but don't recall details

[ddillenger]

I coded out my EGT's and rear O2's, so I don't have any CELs, but will readiness codes be OK? I read up a while back on those, but don't recall details

Depends on how you did it.

[DxC]

Yea depends how u did it. Seems like these days u can't completely delete rear o2. U need to have the o2 heaters on since the new emissions computers test for them.

Basically either run o2 spacers or code out the catalyst efficiency code and leave all the others

/thread

[usmc.S4]

Cant you just get defoulers and space the o2 sensor a bit off the exhaust??

No cats

[DxC]

So what? The spacers take care of the no cat issue. I'm amazed how few people bother to do research and just ask here wanting people to spoon feed the info, then when someone spoon feeds it, they spit it up

The rear o2 just need to measure a diff o2 value than the primaries. This way it thinks the o2 car is working. Spacing the o2 achieves this effect

[usmc.S4]

So what? The spacers take care of the no cat issue. I'm amazed how few people bother to do research and just ask here wanting people to spoon feed the info, then when someone spoon feeds it, they spit it up

The rear o2 just need to measure a diff o2 value than the primaries. This way it thinks the o2 car is working. Spacing the o2 achieves this effect

Ok...I took what he said as put spark plug defoulers in my cats, so replied that I don't have any cats. And I'm so sorry I didn't do enough research for you, I'm an active duty Marine, I'm pretty busy most of the day. All I asked was how people pass emmissions without cats. but since you seem to have another answer, where do I put my secondary o2 sensors if I don't have cats?

[phila_dot]

Yea depends how u did it. Seems like these days u can't completely delete rear o2. U need to have the o2 heaters on since the new emissions computers test for them.

Basically either run o2 spacers or code out the catalyst efficiency code and leave all the others

/thread

You can completely delete the rear O2's with a proper codeout. The emissions computer only knows what the ECU tells it.

IMO, O2 codeout is the only solution. Defoulers can cause other issues.

The only thing to worry about when running catless is the sniffer if your state requires it.

[usmc.S4]

Would I pass with a Jfonz tune with rear o2 codeout?

[dannyn424]

spark plug defoulers or similiar are used as spacers to to space the rear o2 sensors out a couplue of mm from the exhaust stream so it thinks the air is still clean and the cat is doing its job.

[jolio1994]

I heard it's possible to pass with e85? Is this true?

[usmc.S4]

spark plug defoulers or similiar are used as spacers to to space the rear o2 sensors out a couplue of mm from the exhaust stream so it thinks the air is still clean and the cat is doing its job.

Again, no cats. Where am I supposed to put defoulers? Weld them into the test pipes? I'd rather have the rear o2's coded out. Does anyone know if jfonz's tunes with o2 codeout pass emissions?

[DxC]

You can completely delete the rear O2's with a proper codeout. The emissions computer only knows what the ECU tells it.

IMO, O2 codeout is the only solution. Defoulers can cause other issues.

The only thing to worry about when running catless is the sniffer if your state requires it.

Hehe maybe that flies in your state but not in ma and ri now. They purposely reset the heaters or
Something in the test and it should go to not ready- and if it doesn't it red flags

Yea easiest is to code out rear o2 if you can where you are.

Anyway yea throw in rear o2s where ever you want

[phila_dot]

Hehe maybe that flies in your state but not in ma and ri now. They purposely reset the heaters or
Something in the test and it should go to not ready- and if it doesn't it red flags

Yea easiest is to code out rear o2 if you can where you are.

Anyway yea throw in rear o2s where ever you want

Of course, everything resets thats supposed to when it's done correctly. It works in every state.

I know a little bit about this subject.

The sniffer is a little bit tougher.

[bigdo26]

You can completely delete the rear O2's with a proper codeout. The emissions computer only knows what the ECU tells it.

IMO, O2 codeout is the only solution. Defoulers can cause other issues.

The only thing to worry about when running catless is the sniffer if your state requires it.

I think I have 'completely' coded out my rear O2's using TunerPro to modify the bin file per the S4 tuning wiki... any other parameters aside from the below that are needed? I haven't worked on tuning in about a year, so I'm a little rusty

Set these to zero to disable rear cat DTC:
CDKAT - Cat diagnosis in OBDII-Mode.
CWDLSAHK (0x18663) - Code word for probe aging after KAT[31]

If you want to remove your rear O2s entirely, also set these to zero:[32]
CDHSH - Post cat O2 heater diagnosis
CDHSHE - Post cat O2 heater amplifier diagnosis
CDLATV - Lambda sensor aging diagnosis (tv) in OBDII-Mode (inverse: EURO-Mode)
CDLASH - Lambda sensor aging diagnosis (SHK) in OBDII-Mode (inverse: EURO-Mode)
CDLSH - Post cat O2 sensor diagnosis
CDLSHV - Lambda sensor sensor interchange recognition

[ddillenger]

Check the s4 wiki now. There have been a few changes, apparently there is no need to change the error classes, and two additional parameters have been added (esknof).

[bigdo26]

I'll take a closer look at s4 wiki and read up!

[Dr. Funk]

just use the 02 spacers.. weld them in to your test pipes in the event something happens you can swap the test pipes out.. trust me, DXC is right about coding out the rear o2s.. it use to be a simple thing but now you run the risk of getting flagged.. in MA they require you to go back to stock if you get caught. once the spacing is set with your mods you are solid as a rock.

[phila_dot]

just use the 02 spacers.. weld them in to your test pipes in the event something happens you can swap the test pipes out.. trust me, DXC is right about coding out the rear o2s.. it use to be a simple thing but now you run the risk of getting flagged.. in MA they require you to go back to stock if you get caught. once the spacing is set with your mods you are solid as a rock.

If it is done correctly it cannot be detected. There are bits that identify the hardware that is tested/supported, as long as these aren't disturbed then you won't have any problems.

[ddillenger]

I think he's saying that they reset readiness, and if it doesn't go to failed/not completed (stays ready), they fail you.

[phila_dot]

I think he's saying that they reset readiness, and if it doesn't go to failed/not completed (stays ready), they fail you.

And I'm saying that if it's done correctly then it resets just like it should and readiness sets again after the required driving cycles.

[S4 00 2.7]

And I'm saying that if it's done correctly then it resets just like it should and readiness sets again after the required driving cycles.

This. phila-dot knows a thing or two about tuning.

[ddillenger]

I wasn't arguing with him. Just asking him to clarify.