Failed Emissions Twice - Colorado

[Faded95]

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!

 

[ErikTande]

I'd try seafoaming it, then change your plugs, run it for a few days and try again.

I HATE Colorado emmissions. I bought my car with 17" wheels on it, went in to get tested, and they wouldn't do it, because the car came with 16" wheels orginally. So I had to put 16's on before they'd even let me test. I was in the process of restoring the OEM 16" wheels anyway, but still, f*ck that noise.

 

[black97spyder]

My cousin lives out there and personally knows some emissions testers there and there is away around it but not everybody is for this way... you could always bribe the guy testing it with a quarter ounce of (now legal) medicinal smoke and he will make sure it passes, or at least thats what she says.

im not sure id be balsy enough to do that but my cousin says people do it all the time for their "hopped up cars" ha

 

[Faded95]

I'd try seafoaming it, then change your plugs, run it for a few days and try again.

I HATE Colorado emmissions. I bought my car with 17" wheels on it, went in to get tested, and they wouldn't do it, because the car came with 16" wheels orginally. So I had to put 16's on before they'd even let me test. I was in the process of restoring the OEM 16" wheels anyway, but still, f*ck that noise.

Erik - forgot to mention, I put new NGK BPR7ES in a month ago...

Crazy about the wheels. At the first test I was talking with a guy who was having his Forrester XT w/ 2.5 STI swap in it, his passed, mine didn't.

 

[bergz0]

X2 on the seafoam. That should clean her out pretty good. You do have a cat on it right?

 

[ErikTande]

Erik - forgot to mention, I put new NGK BPR7ES in a month ago...

Crazy about the wheels. At the first test I was talking with a guy who was having his Forrester XT w/ 2.5 STI swap in it, his passed, mine didn't.

Ah, do you still have the old plugs? I would put those back in, seafoam it, then put the new ones back it. Seafoaming your car will foul the plugs.

http://www.dsmtuners.com/forums/newbie-forum/467261-seafoaming-my-talon-video.html <--- not my video, just an example

If you google "seafoam emissions" you'll find a bunch of posts and videos of people that did that trick and passes emissions. I just seafoamed my car and replaced the plugs and wires tonight.

 

[Faded95]

I've considered seafoaming but the test results went from one extreem to another - lean to rich, so I wanted to address what may have caused that swing before I start cleaning everything out. I'm concerned that seafoaming will mask the root cause of the problem. I'm not against seafoaming, in fact I love the idea of a clean engine, but I want to see what actually caused me to fail CO after I passed last week.

 

[T is for TURBO]

Sounds to me like you might need a new catalytic converter

 

[Faded95]

Sounds to me like you might need a new catalytic converter

Then why would it have had such low CO levels last week and so high this week. The cat is a flowmaster high-flow unit that's 3 years old. I'm not saying it's not the issue but I highly doubt it.

 

[T is for TURBO]

Bah, I missed the part where you said your cat was only three years old

 

[SonySlave]

I've had a friend for the last 8 years that's had to deal with this in Washington State every two years. This is coming from a 700hp 1G that passes every time with a straight pipe and fully modded.

- 1/8-1/4 tank of 87 octane
- Add 2 gallons of denatured alcohol to gas tank
- Hot plugs (5 or 6 heat range)
- New air filter
- Retard timing as much as possible without causing misfiring (0* seems to work well, maybe more)
- Raise idle to at least 1000 or higher depending on the idle speed limit in CO

DO NOT BOOST THE CAR LIKE THIS

 

[Faded95]

I swapped my Eprom back in last night and I'll put on some miles on so it can learn the fuel maps. I'll probably turn the boost down for the next test too...

 

[Dude McGee]

Just a thought here- if your egr/ports were dirty enough, theres the possibilty that the gunk balled up when you cleaned it. I had that happen in an old blazer, where carbon wadded up and stopped the valve from operating properly. It also threw an emissions code when this happened though. Should be something quick and simple to recheck it, just in case.

 

[Faded95]

Just a thought here- if your egr/ports were dirty enough, theres the possibilty that the gunk balled up when you cleaned it. I had that happen in an old blazer, where carbon wadded up and stopped the valve from operating properly. It also threw an emissions code when this happened though. Should be something quick and simple to recheck it, just in case.

But doesn't a faulty EGR cause a lean condition and high NOx? That was part of the problem the first time, after I cleaned it out the NOx was much lower.

 

[Dude McGee]

I might have tjis backwards but if its stuck closed, its not reintroducing exhaust and burning unburnt fuel, causing a "rich" condition, which I think raises CO. I could have it backwards though, thought it could be worth rechecking before you spend money.

 

[Faded95]

That would actually cause a lean condition because the c.c. would be getting a higher volume of fresh air not mixed with exhaust gasses. I believe the restricted flow through the EGR was one of the main reasons my first test was high on NOx.

 

[sirbow2]

you can use E85 too (the denatured alcohol)

 

[Faded95]

Small update:

In my first post, in item # 3 I described a fitting with a small hole btw the boost controller and the wastegate. because it was leaking during the boost leak test and I couldn't figure out why it was there and all boost leaks are evil...I took it out and replaced the line. That fitting kept coming back to my mind and after I did some research on ball and spring MBC's, I realized that this fitting was indeed supposed to be there so the wastegate fully closes when you get out of boost (Hallman MBC's have a similar setup).

I had noticed that after I shifted from 2nd to 3rd the boost was much lower and the car seemed to bog down a little - after I replaced the fitting the car boosted normally.

So I'm guessing that this was causing a rich condition during the test because the ECU was sending enough fuel for 15psi eventhough the car was only making somewhere like 7 or 8psi after a gearchange.

Thoughts?

I've not yet gone back for my third test - will do that later this week.

 

[Kapok6]

I passed with no cat on a 2 speed test.

change your oil and plugs. go in with 1/4 tank of gas and add like 1qt of denatured alcohol. when you get there, retard the timing a lot.

worked for me...

 

[Faded95]

I passed with no cat on a 2 speed test.

change your oil and plugs. go in with 1/4 tank of gas and add like 1qt of denatured alcohol. when you get there, retard the timing a lot.

worked for me...

I have new plugs in it (mentioned above), also did a fresh oil change last night BUT THAT'S NOT WHAT THIS THREAD IS ABOUT! All the tricks mentioned in this thread have been mentioned in other threads (I did search and reviewed ALL of the other threads on this subject) - I'm not looking for quick tricks to pass. I'm trying to figure out why the results were so different btw the tests - that's why I included so much detailed information above.

I'm looking for thoughts on my last post regarding the wastegate vs. boost controller bleed hole and whether or not that would cause a rich mixture.

Thanks!

 

[Mello]

Yes a air leak will cause a rich condition with MAF sensors like ours. The hole will let air out that the ECU thinks is there but is missing and the correct fuel will be off for the amount of air the ECU is thinking it has to add fuel for.

 

[Faded95]

Yes a air leak will cause a rich condition with MAF sensors like ours. The hole will let air out that the ECU thinks is there but is missing and the correct fuel will be off for the amount of air the ECU is thinking it has to add fuel for.

Mello - this is precisely what my speculation was, thank you for your response. I'll go and test again now that I have a properly closing wastegate.

 

[Faded95]

Update:

Failed a third time! This time the results mirrored the first test with high NOx.

HC: 0.6736, limit is 1.2000
CO: 4.9224, limit is 15.000
NOX: 3.233, limit is 2.5

The only major thing I did was re-install the boost controller fitting that had the bleed hole. This is getting frustrating, I'm back to square one. Time for another BLT I guess...

 

[hotrodssnova]

Have you tested your egr? It should open when vacuum is applied to one of the ports, and will be closed with no vacuum or when pressure is applied to the other port. I bypassed my thermal switch and hooked it straight to the throttle body when I went for the sniffer, 2 speed test and passed.
You also need to get that car good and hot before you get the test. The hotter the car, the better.

 

[spyderdrifter]

Have you checked your o2 sensors? Just because the cat is only 3 years old, doesn't mean it can't be bad. Any kind of contamination to it can cause it to fail, which also includes higher than normal temps. Running lean or rich too long will foul it out as well. I'm not saying this is your problem, but could be a possibility. What kinds of running conditions has your car seen. Have you checked for cracks anywhere? One example is if your exhaust manifold is cracked, it'll draw in more air and your o2 will throw a false lean code.

Since you cleaned your EGR, I think you should run a vacuum test on it and the solenoid just to make sure it's operating under proper conditions.

Also, since your 2nd fail was due to high CO, that indicates a bad PCV valve.
While I'm on this, high HC can indicate a fault in the ignition system which includes spark plugs & wires, ign coil, & ign timing.
And as you've already dealt with it, the EGR is the main culprit for NOx.