High NOx!!
Thread Starter
Staging Lane
Joined: Jul 2005
Posts: 95
Likes: 1
From: Brighton, CO
High NOx!! Hey guys - I did a search and didn't find anything that i could use, also I didn't see an emissions thread, so I figured I would post it here...
I have a 2000 Z28 with only 45,000 miles on it - after an oil change, fluids check, battery charge, new gas, etc it has failed CO emissions (twice now - first time was due to bad gas not fully being burned out)... It sat for about 3 years and now I'm getting a high NOx reading failure (1.8205 reading on a 1.5000 limit).
The error is:
"High NOx Readings: High NOx readings are the result of high combustion temperatures and/or pressures."
A little about the vehicle - I have 1" 7/8 Texas Speed headers with a TSP catted Y and an LS6 intake & manifold (so no EGR) that was put on 3 years ago and everything else in the engine bay is stock (MAYBE 500 miles on the new parts ...). Camaro has passed emissions with the new parts on before, but after it sat in storage for 3 years, it's failing.
I'm not throwing any codes, nor any visible smoke or funky smells -- I ran a can of seafoam through the engine, but it didn't help ...
Has anyone else had this issue?? Any suggestions? I've possibly heard of a bad injector, but not sure how to go about checking those without replacing them all ...
Here's my readings/limits:
HC GPM 0.8436/1.2000 [PASS]
CO GPM 2.7514/15.0000 [PASS]
CO2 GPM 472.0603 (no limit?)
NOx 1.8205/1.5000 [FAIL]
I have a 2000 Z28 with only 45,000 miles on it - after an oil change, fluids check, battery charge, new gas, etc it has failed CO emissions (twice now - first time was due to bad gas not fully being burned out)... It sat for about 3 years and now I'm getting a high NOx reading failure (1.8205 reading on a 1.5000 limit).
The error is:
"High NOx Readings: High NOx readings are the result of high combustion temperatures and/or pressures."
A little about the vehicle - I have 1" 7/8 Texas Speed headers with a TSP catted Y and an LS6 intake & manifold (so no EGR) that was put on 3 years ago and everything else in the engine bay is stock (MAYBE 500 miles on the new parts ...). Camaro has passed emissions with the new parts on before, but after it sat in storage for 3 years, it's failing.
I'm not throwing any codes, nor any visible smoke or funky smells -- I ran a can of seafoam through the engine, but it didn't help ...
Has anyone else had this issue?? Any suggestions? I've possibly heard of a bad injector, but not sure how to go about checking those without replacing them all ...
Here's my readings/limits:
HC GPM 0.8436/1.2000 [PASS]
CO GPM 2.7514/15.0000 [PASS]
CO2 GPM 472.0603 (no limit?)
NOx 1.8205/1.5000 [FAIL]
Last edited by mike3605; May 28, 2014 at 10:41 AM.
Thread Starter
Staging Lane
Joined: Jul 2005
Posts: 95
Likes: 1
From: Brighton, CO
in the suck state i live in, years ago when emissions did do tail pipe sniffer tests the class and culture of people that worked at the handful of DMV emission places were quite corrupt and stupid. they tried to do a gasoline sniff test on my diesel until the boss of the place told them it was diesel you don't do that, and after plenty of findings of them selling stickers out in the parking lot and favoring certain people coming through and not others the state killed it all and now we go to independent garages where they only check the OBD-2 port.
so i would not overlook the honesty of the people performing the test nor the accuracy of their equipment.
so i would not overlook the honesty of the people performing the test nor the accuracy of their equipment.
12 Second Club
Joined: Sep 2005
Posts: 4,273
Likes: 0
From: Bucks County, Pa.
in the suck state i live in, years ago when emissions did do tail pipe sniffer tests the class and culture of people that worked at the handful of DMV emission places were quite corrupt and stupid. they tried to do a gasoline sniff test on my diesel until the boss of the place told them it was diesel you don't do that, and after plenty of findings of them selling stickers out in the parking lot and favoring certain people coming through and not others the state killed it all and now we go to independent garages where they only check the OBD-2 port.
so i would not overlook the honesty of the people performing the test nor the accuracy of their equipment.
so i would not overlook the honesty of the people performing the test nor the accuracy of their equipment.
When I lived in Joyzee, I went to the now closed Westfield inspection station, and the g working there was intent on failing me for no driver's side catcon, when I had a FULL, COMPLETE, AND 100% FUNCTIONAL emissions system on the car, including stock iron exhaust manifolds, full EGR AND A.I.R. systems and factory stock catcons.
The thug just could not see the driver's side catcon with his mirror on a stick.
So at the end of the line AFTER he had already given me the fail sticker, I pounded on the manager's door, brought him over to my open hood, and SHOWED him the 'missing' catcon!
He then scraped off the fail sticker and pasted on a good one.
Parsons (private company which does N.J. state inspections for them) DOLTS!!!
10 Second Club
Joined: Jul 2008
Posts: 224
Likes: 0
From: Columbus Ohio
I'm not an expert on emissions testing since we don't have them here in Ohio, but i thought I'd share my two cents. It seems to me that the EGR would have helped to bring the NOx levels down, the 2001-2002 cars without EGR used a different camshaft with some "EGR like" overlap so they didn't have to use an EGR valve. Obviously a stock 02 cam shouldn't be too expensive, or I know some cams are somewhat emissions friendly, something like this and the proper tuning would be the direction I'd go.
TECH Regular
Joined: Oct 2011
Posts: 407
Likes: 2
From: Keller Tx
I'm not an expert on emissions testing since we don't have them here in Ohio, but i thought I'd share my two cents. It seems to me that the EGR would have helped to bring the NOx levels down, the 2001-2002 cars without EGR used a different camshaft with some "EGR like" overlap so they didn't have to use an EGR valve. Obviously a stock 02 cam shouldn't be too expensive, or I know some cams are somewhat emissions friendly, something like this and the proper tuning would be the direction I'd go.
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12 Second Club
Joined: Sep 2005
Posts: 4,273
Likes: 0
From: Bucks County, Pa.
I am guessing an precise tune without the '01/'02 cam just will not work as far as a sniffer test goes, correct?? 
I am now thinking about dumping my EGR system, and although my area has no sniffer test currently (OBD 2 plug in, and 'visual' ONLY), I am afraid that they will initiate one in the future, especially for older rides like mine.
I am now thinking about dumping my EGR system, and although my area has no sniffer test currently (OBD 2 plug in, and 'visual' ONLY), I am afraid that they will initiate one in the future, especially for older rides like mine.
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