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Failed Emissions Twice - Colorado

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Faded95

10+ Year Contributor
75
2
Sep 15, 2011
Fort Collins, Colorado
I've read all the emissions threads on here and I'm still stumped:

Last week I failed for high NOx so I did a boost leak test, cleaned out my EGR, cleaned out my throttle body, installed a new BISS o-ring, installed a new ISC o-ring, and fixed a leak in my IC-pipe.

First Test:
HC GPM 0.5796 - limit is 1.2000 - PASS
CO GPM 5.9712 - limit is 15.000 - PASS
NOx GPM 2.8003 - limit is 2.500 - FAIL

Today my NOx was well under the limit but my CO skyrocketed, it's like I went from slightly lean to really rich.

Second Test:

HC GPM 0.7721 - limit is 1.2000 - PASS (but higher than last week)
CO GPM 22.1448 - limit is 15.000 - FAIL
NOx GPM 2.1075 - limit is 2.500 - PASS

What would cause my CO to increase so dramatically? Here are my speculations:

1. I used throttle body cleaner liberally on my throttle body, EGR and EGR ports; could that have caused higher CO readings?

2. I filled up with gas this morning; could a full tank cause higher CO readings?

3. I removed a fitting in the line running from my wastegate to my mbc that had a bleed hole in it; the mbc is a homemade unit by the prev. owner and I'm not sure of the purpose of the bleed hole here. I removed it b/c it was leaking during the boost leak test. Could this cause high CO readings?

4. Could the ECU still be learning the fuel trims? I've only driven 25 miles since all the above mentioned work was done.

5. Longshot here - the ECU that's in the car isn't the same one that was in it last time I passed emissions. I swapped them to try and correct an IAC issue but the ECU wasn't the problem so I still have my old Eprom waiting to be swapped back in.

Any other suggestions? I've read doing an oil change helps but i passed CO last week so it has to be something that changed with the work I did over the weekend.

Info about the car: 95 turbo awd, 3" exhaust w/ flowmaster high flow cat (cat is 3 years old), stock fuel system, 14b turbo, boost set at 15psi, NO wideband, NO engine management system.

Any help would be appreciated - Thanks!
 
Won't a faulty O2 sensor throw a code? I also have an EGT and never get much higher than 1000 degrees, most of my driving is in town and I don't get into boost for any length of time.

I'm also running at 15 psi on a 14b with a stock fuel system - I thought I was okay at that flow but could this be too much for my fuel system?

I'm considering just getting a new EGR, the car passed fine two years ago and there haven't been any mods since and I'm running at the same boost level. Thoughts?

-Spyderdrifter, I envy you not having emissions in El Paso County - that's where this car came from and I had to install a cat when I bought it.
 
Won't a faulty O2 sensor throw a code? I also have an EGT and never get much higher than 1000 degrees, most of my driving is in town and I don't get into boost for any length of time.

I'm also running at 15 psi on a 14b with a stock fuel system - I thought I was okay at that flow but could this be too much for my fuel system?

I'm considering just getting a new EGR, the car passed fine two years ago and there haven't been any mods since and I'm running at the same boost level. Thoughts?



Yes, a faulty o2 will throw a code, however, if the o2 is throwing a code, it may not be the o2. Which is why I mentioned the false lean condition. The o2 only reflects what it's reading, but won't tell you what the cause is. I can't comment on your fuel though, not too sure on it, and can only speculate.

-Spyderdrifter, I envy you not having emissions in El Paso County - that's where this car came from and I had to install a cat when I bought it.


I'm gonna be envious of me too. I'm possibly moving up to Denver in spring, and will then be in the same boat :( I still got my factory exhaust in storage, but I think the cat is bad, so I'll need a new one too.
 
I'm not throwing any codes so I'm going to do a boost leak test, run some fuel system cleaner through and research flow for the 14b, maybe even get a new EGT. This car is eating through my car maintenance budget and my patience!

I'm gonna feel pretty stupid if I just turn down my boost and it passes.
 
I just ordered a new EGR, plop that in and hopefully I'll pass since I only have a couple of weeks to get new tags.

I'll probably turn the boost down before my next test too just to be on the safe side even though the stock fuel system should be able to handle 15 psi on the 14b.
 
So in the process of changing the EGR valve I shined a light down on my exhaust... my flex section is covered in carbon as well as my subframe right above it. I think I may have found the reason I can't pass emissions! I'm going to test the old EGR to see if it's still functioning but I'm guessing the exhaust leak is the issue. Time to make an appointment at the exhaust shop.

the old EGR is functioning properly under vacuum, I have an appointment at the exhaust shop today to get a new flex section.
 
So in the process of changing the EGR valve I shined a light down on my exhaust... my flex section is covered in carbon as well as my subframe right above it. I think I may have found the reason I can't pass emissions! I'm going to test the old EGR to see if it's still functioning but I'm guessing the exhaust leak is the issue. Time to make an appointment at the exhaust shop.

the old EGR is functioning properly under vacuum, I have an appointment at the exhaust shop today to get a new flex section.

So is there a leak in the flex? Good luck, keep us updated!
 
Yeah a pretty big leak, I guess the flex section was old and tired. While it was on the rack yesterday you could see the exhaust leak at idle - I've got a new flex section going in today. From what I've read a leak upstream of the cat will cause high NOX readings, I'll re-test late this week and update the thread.
 
Change the oil just before the test.

Dirty oil is so full of hydrocarbons that this junk will send many red flags of bad emissions readings.


-DSM

I guess you missed the part of the thread where I said I did a fresh oil change just before my third test. I don't mean to bag on you but it's one of my biggest internet forum pet-peeves when someone replies without reading through the thread. :nono:
 
Sorry on that, but it could be a tip for future owners with passing emission problems in doing the oil changes prior to the sniff test...since I had the basic same problem in passing until one sniff test place gave me this tip in which it did allow me to pass on my next visit.

Thx
 
When they test your car, how are they driving it? Are they rolling gently into boost or are they flooring it to catch up? If they aren't driving it gently you could potentially try going to another place to emission test it or do like some people have done and disconnect the wastegate flapper from the actuator so you get next to no positive pressure out of the turbo.
 
Sorry on that, but it could be a tip for future owners with passing emission problems in doing the oil changes prior to the sniff test...since I had the basic same problem in passing until one sniff test place gave me this tip in which it did allow me to pass on my next visit.

Thx

I don't mean to be a jerk - I only responded that way because it was taking the thread off subject. Yes a fresh oil change helps if you're HC readings are high but my HC's have never been high. There are plenty of emissions/smog threads on the forums that help with tips & tricks to pass and I've read them trying to figure out my issues.

I'm planning on testing again tomorrow and I anticipate passing since I just replaced my leaky flex section with a new one. Funny thing, I can hear my induction noise and turbo spool a lot more since there's no more leaky exhaust! :thumb:

When they test your car, how are they driving it? Are they rolling gently into boost or are they flooring it to catch up? If they aren't driving it gently you could potentially try going to another place to emission test it or do like some people have done and disconnect the wastegate flapper from the actuator so you get next to no positive pressure out of the turbo.

They haven't been flooring it - I think I'll pass now with the exhaust leak fixed. On another note, nice electric blue 1Gb - I used to have one like that, electric blue 1Gb's are by far the best looking of all the DSM's IMHO.
 
They haven't been flooring it - I think I'll pass now with the exhaust leak fixed. On another note, nice electric blue 1Gb - I used to have one like that, electric blue 1Gb's are by far the best looking of all the DSM's IMHO.

Thanks! I agree, but I'm biased. :) Good luck on the retest.
 
In the two counties in our state that sniff cars is they do two sniff tests: 1st test is during idle, and the 2nd test is with the motor at 2000rpm, which is close to highway speed in top gear.

Here we have a rolling 2 speed test, they put the car on a dyno and accelerate under load to I believe 20 mph and hold then a second pull at 60 mph I think. I'm fairly positive I'd pass a sniff test like you have but here they like to drive your car till it breaks on the dyno and then collect your money. Nothing better than state employees riding your clutch! The first time I tested, I watched them drive an old lady's Chrysler LHS until the radiator blew - these guys (and gals) make me very nervous!

8/22/13 - 1:17 pm:

And another FAILED test! 4 now. NOx readings were about the same as the last time, I even turned down the boost to 12-13psi. I'm going to do the free inspection with the state mechanics this afternoon.

Summary of what's been done:

Removed & Cleaned TB
Removed & Cleaned EGR
Cleaned out EGR Ports on the intake manifold
Tested EGR under vacuum - functioning properly
Cleaned out EGR again
Fixed a few boost leaks
New O-ring on ISC
New O-ring on BISS
New Flex Section on exhaust
Turned Boost down from 15 to 12-13psi

Also of note, my EGT never went past 1200* in the warm-up passes I did on the interstate. I'll post an update after my appointment with the state mechanic today.

8/22/2013 - 4:00 pm

The state inspector/mechanic thinks I have a non functioning cat. He also thinks that when we go to big exhaust that are single wall we loose a lot of the heat required to light off the cat. His logic was that a cheap ($80) cat coupled with a bigger exhaust are what are causing me to fail. I'm going to bite the bullet and get a new legit cat ($340 installed)...ouch. If I wasn't planning on keeping the car, I'd get another cheap one to throw on it to pass. At least the car is fun, otherwise it'd be on the chopping block!
 
Last edited:
I'll be testing my car tomorrow, I just had this CAT installed with the rest of my exhaust on Monday.
Thunderbolt 3" Spun Catalytic Converter

I'll let you know how it goes.

I'd be interested to hear how it does not only this time but the next time you have to test. The tech told me that these lower priced aftermarket cats don't have the paltinum or rhodium in them, they work great when they're brand new but taper off quick, he said after as little as 4000 miles they start to fail. The exhaust shop I've been going to (a very reputable shop here and recommended by the DSM community) echoed that sentiment. I wish I had a way to test only the cat to see if it's working to confirm what they're telling me.
 
The exhaust shop I use here can test converters They drill a little hole right before the cat and stick a probe in. Then they stick the probe in post-cat and see if there is a difference in the readings. I don't know if other places would do it, but it's probably worth looking into.
 
I'd be interested to hear how it does not only this time but the next time you have to test. The tech told me that these lower priced aftermarket cats don't have the paltinum or rhodium in them, they work great when they're brand new but taper off quick, he said after as little as 4000 miles they start to fail. The exhaust shop I've been going to (a very reputable shop here and recommended by the DSM community) echoed that sentiment. I wish I had a way to test only the cat to see if it's working to confirm what they're telling me.

They tested my car this morning. All readings were well below limits, but they failed me because they said I didn't have a 3 way CAT on the car. I told them I did, that it was OBDII EPA legal, and that I have the receipt, but they said it didn't matter because they didn't see it when they looked.

W

T

F

:ohdamn:


So I asked them how my emissions would be so low without a CAT, and they said they wouldn't be.

NO SHIT

Now I have to call the state number and get someone to sign off on the CAT. If the state inspector won't, I'll have to change it. Just because the moron looking for it didn't see it.:notgood:

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I know In denver you just tell the guy youve been having a hard time getting the car to pass and ask if he'll take a "green pass", thats all you have to say, its either yes or no, no harm either way but you wont know unless you ask.
 
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