mike3605

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]

dailydriver

Running (slightly) lean (whether from a tune, vacuum leak, or bad injector) can also cause higher NOX readings.

Did you log/check the fuel trims yet??

mike3605

No I haven't checked that yet ...I'm not sure how to check that - i will have to research a bit

1 FMF

iTrader: (1)

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.

dailydriver

Tell me about it!

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!!!

ND2RACE

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.

Jr.Samples

This ^^^

dailydriver

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.