Vorsicht

Just failed CA smog due to High NOX (double the max values). I was getting an intermittent 1124 code (short/ground) on the O2 sensor before the test, could that affect NOX values? I have replaced the o2 sensor but was wondering if anything else should be checked b4 I bring it back in for re-test.

In reading up on NOX values EGR comes up a lot. Is there a way to test this valve? Do we even have one on our cars?

Thanks


PS all other values passed (HC, CO, etc..)

windydog

Post your results,due to high cylinder temps

Vorsicht

Here are the results:

Vorsicht

I just discovered something new. Just aft of the o2 sensor there is a threaded hole on the Cat. I believe this is there to secure the cage that protects the o2 sensor. This cage has been missing for a while. This hole is letting O2 enter the cat right in the vicinity of the sensor. I'm guessing that added oxygen at the 02 sensor would cause a lean mixture and hence the hig Cyl. Temps & high NOX.

Anyone concur?

I have plugged the hole with a screw.

pp000830

Seems you found something significant from what should be expected, a hole in your exhaust. Do you pay for retesting or are there a limit in the number of tests you can take the test, if not just plug the hole and take it back and see what happens.

helmet993

When they tested your car did they set a fan in the front right to keep air moving across the oil cooler? That single fan alone significantly impacts my NOx when smog testing. I have played with that on the 5 gas analyzer as well.

Since you have a 95 maybe you found part of the concern with that missing screw though...an exhaust leak can cause high NOx depending on where the leak is in relation to your cat and o2 sensor.

Vorsicht

$30 for a retest within 30 days. I don't believe there is a maximum no. of tests but this is CA! so I'd like to pass on the next go-round.

Vorsicht

Yes, and the hole is just an inch or two away from the O2 sensor. No fan. Maybe I will set it to high for the re-test.

nine9six

Peter,
I believe you to be correct in your discovery analysis. I'd fix it, get things good and hot for a while, and go for a retest.

If previous test results (did you keep prior results) are well within range, you've hit the nail on the head. Most likely you lost the plug between then and now.

BTW, 95 or later model? 2 or 4 O2 sensors?
EDIT
Looks 95 from your Part Number Help, post.

http://www.pcarworkshop.com/images/d...4_-_p1126_.pdf

Check out No 1 trouble area to check.

Vorsicht

Yes, two years ago I passed no problem. Nox was well under the limit.

I'll report back after re-test.

OverBoosted28

Worst part of this whole "smog inspection" debacle? It has little/to no effect on harmful pollutants. Probably, the last 3 decades of reductions, were wiped out during this year's fires. Sorry, just hate the crap this state forces on law abiding citizens, that has no real positive outcome.

goofballdeluxe

Well, I lived in Los Angeles in the 1970s, and the air was foul. Far worse than it is today. Smog checks are a big reason why the air is better now. So there has been a real positive outcome having smog controls here.

We can't control every forest fire. We can control, to a great extent, how many pollutants are emitted into the air we breathe by the emissions regulations. Forest fires may wipe the gains out, but imagine if we had no emissions controls AND forest fires.

Yes, they're a pain in the ***, but we're better off with smog checks, if you're a fan of breathing cleaner air

nine9six

Truer words were never typed^^^!

The 60's were even worse (Long Beach, 20 mi. south of LA)...As a kid, on bad smog days that you could see; I can remember my lungs hurting when taking a deep breath!

Torrence and Wilmington oil refineries, located in the middle of LB and LA, were burning at full tilt, and leaded 98 ron was available @ $ .25 a gallon during gas wars (remember those?). ☺

But the air really suxed back then!

OverBoosted28

I'm sure vehicle efficiency, unleaded fuel, and industrial pollutant reductions have helped. My gripe lies more with the unchecked diesel trucks that are exempt from smog. Maybe a more acceptable format. Classic, sports, and performance car owners shouldn't be held accountable for the 90% of the pollutants, that 7-10% of the vehicles are regularly emitting.

Kika

I grew up in the 70s in a house about 4 miles due south of Mount Wilson. Most days we could NOT see the local mountains. When it was REALLY bad, we had First Stage Smog Alerts, and kids were not allowed to go outside for recess. There were days I would get home from school and my eyes burned so bad, my mom would give me eye drops and put warm compresses over my eyes.

Now, I live 30 miles away from those same mountains, and on most every day of the year, I can see them.

From my perspective, the air quality in Los Angeles has drastically improved in the past 40 years.