I have a 2003 S. Less than 35K miles.
It was time to do a California smog test.
It failed NO.
1338ppm at 15mph.
1258ppm at 25mph.

I was getting a PO420 until I replaced the post cat O2 sensor a few weeks ago and have not had any cel lights since.

Could this be a bad CAT although no cel lights?


My car has 15% pulley, removed the CAI and replaced it with the old stock one, miltek head/cat and magnaflow catback. 91 octane.

Any help would be greatly appreciated,

Thanks in advance,
kmickey

 

I had a car fail with a high flow cat before because it was a 2 gas and not a 3 gas cat. You need to make sure the cat will take care of NOx or you will fail for sure.

 

Mickey, I'm glad you started this thread. Hopefully other Militek header/cat owners, particularly in CA, will chime-in...

If you still have the stock header, start getting it cleaned-up and ready for swap. IF you do not have one, let me know.

Either way, I'd still do a Seafoam treatment...

 

Do you have an OBD scan tool? If so monitor the B1S1 and B1S2 parameters. The first one should fluctuate from about .2 to .8vdc; the B1S2 should be above .5 at a warm idle.

 

All I can say is, I'm glad I saved my stock header and intake California is so out of wack

 

there are lots of aftermarket parts that don't do what they're supposed to do. It's possible to pass smog, and have power, and have cleaner air...

But what do I know....

Matt

 

Yea, I still have my original exhaust header/cat. Not looking forward to re-installing it - if that is the problem.
I reinstalled my original CAI for the smog test. The Alta CAI would not pass visual inspection.

kmickey

 

I'd try the sea-foam as well. Plugs are a plus too. Maybe dump in some 100 octane gas as well. NOxs are formed from high combustion temps as well. If there's carbon build up that won't help for sure. It insulates the combustion chamber surfaces, and increases compression.

What's a passing grade? Are you close or way way off? Another thing to try is to tie the bypass valve open. The car will be a dog, but it will be off boost.

Matt

 

Matt,
Please tell what you know. I would like to pass smog, have power...
I have a cheap code reader that only displays any code and then clears it.
I'm not throwing any codes.

Other emission test results:
%CO2: 9.7/15mph 11.0/15mph
%O2: 7.2/15mph 5.6/25mph
HC pmm: 50/15mph 26/mph
CO%: 0.23/15mph .19/25mph
NOx ppm: 1338/15mph 1258/25mph

At least I'm not a gross polluter.

 

I really like the idea of an aftermkt header having a flanged cat. This is one of the reasons why, assuming the cat is the problem... Either way, cats fail, and swaps are much easier than the whole header.

I'm not due for my first smog until the Fall, even though my MINI is a bit older than Mickey's. We guess it's a county thing... If I wanted to do a test run, out of curiousity, is that possible, without repercussions?

 

NOx max is 459/15mph and 746/25mph.
The smog tester said he could smell my exhaust and tell it seems suspect.
He then went over the car with a flashlight and asked of my car had been "chipped". Of course not, I replied.
I'll try the seafoam, 100 octane and new plugs.
kmickey

 

Read this thread....

http://forum.doityourself.com/automo...-high-why.html

While its for an older car, all the symptoms are discussed and you can figure out the order to best attack it.... I'm guessing

SeaFoam
EGR (cheap and easy)
Swap header
02 sensors

Matt

 

have you really modded your ecu, if so which one?

 

Here is the actual test results:

https://www.northamericanmotoring.co...mog_failed.JPG

 

So what are you saying? Intakes and headers don't work?

 

Yes that would be cool, flange them. I was told new cats have to be marked on both ends and visable from 5 feet.

 

I'm saying that there are lots of cats sold that aren't effective. But they are sold as "smog legal" cats for cars. What's true is that very, very few have exhaust gas analyzers, so who's gonna know?

And yes, based on the testing I've done, there are lots of parts sold that don't work as implied or stated.

Matt

 

I guess if the header must come-out, I'd use that opportunity to cut-off the cat and flange the ends, assuming it is still ok. Then, get a stock cat, or remove yours from the stock header, and flange that also, so both are the same length to slip right in between the header and and center pipe...

Swaping cats is then just a matter of 4 bolts/nuts.

The SuperSprint header and the copies of it allow for this, and I wish more did as well.

Mickey, I know this doesn't help you now though... I'm glad Matt also chimed-in on the Seafoam treatment. He started a good thread here on that product. The more I think about it, with your minimal mileage, I can't imagine you have a significant amount of carbon build-up though. For like 10 bucks (2 cans, fuel & oil), it certainly is an easy and cheap first step...

 

Thanks, very logical. I did replace the post cat O2 sensor.
Factory header has a pre-cat in addition to the regular cat.
Wondering if I replaced the miltek cat with another, would I be in the same boat.
I believe all new cats 1991 and newer are of "3 gas" type.
No EGR system for us.
Reading this, makes me wonder if I have a lean condition?
http://www.autoshop101.com/forms/h56.pdf

 

Interesting read...

It said that with the reduced capability of the cat converter, NOx tends to decrease, not increase like yours...

A high NOx usually is indicative of abnormally high combustion temps, so too lean could be culprit. Not enough air intake would be a thought, but this test is at low demand, so even if your stock filter is not exactly clean and flowing well, I don't think lack of air is the issue.

Could be the tune alright and/or the cat I suppose...

 

Pretty sure anything pre-cat is illegal unless CARB certified here in California, so headers are no go, even with a "legal" cat. Sucks

 

Technically, I do believe you are right. In practice, as we saw with Mickey's MINI, with an aftermkt header and cat, he passed the visual. Not exactly in plain view, and to the untrained eye, that person probably wouldn't know. The cat though is something that might motivate a look under the car... and having a MINI logo stamped on it (as with the stock cat), should make for smooth sailing...

 

Look what was headline of my morning newspaper today:


President Barack Obama was to issue overnight regulations allowing California and 13 other states to set tougher car emissions and fuel efficiency standards, a sharp reversal of Bush administration policy.


So whats next for us Californios? No farting in our cars?


Oh, and don't laugh all you peeps from other states, YOUR NEXT!

 

Is you say that you say you replaced the post cat O2 sensor. Swap that one with the pre cat one, as that one is used for fuel trim. The post cat one is to see if the cat is working! Anyway, if your mixture is lean, this could be one contributor.

Matt

ps Jiminni, just drop the off topic smog laws stuff before you really get me going. It would be a favor to us all.

 

Ahh. this thread is about "Smog stuff".