ok its been awhile and i do not know what is up with my firebird. i passed everything with flying colors except for the NOx when it went through emissions testing and its getting worse each time i take it through, thing is im not pulling a single trouble code any ideas?

 

Is the '86 an automatic or manual trans? Manual tranny'd '86 2.8's came with an AIR pump, automatics didn't (in '86). The AIR pump forces fresh air into the catalytic convertor to help convert the oxides of NO and CO into NO2 and CO2. (AIR pump adds extra air, cat uses the extra air to add one oxygen molecule to NO to get NO2, etc.)

The EGR system also reduces NOx. NOx is a byproduct that occurs under high pressure and high heat- exactly what a performance car needs. By reintroducing exhaust gas into the intake, the combustion is "cooled"- why? Because the exhaust gas isn't as volatile as fresh oxygen, so there's less of an explosion.

But, you ran on a dyno, right? In NJ, they don't raise the car faster than 15 mph. The test is the ASM-5015, which is 50% load at 15 mph. EGR shouldn't kick on until 40 mph or so... so I don't think EGR could affect the NOx's.

Is the cat old, or gutted?

 

the car has an automatic transmition and the cat is 3 years old and i dont think its that. i suspected the egr but shouldnt it be pulling up a code for that?

 

How's the rest of the ignition system and fuel system and air system? A malfunction in that could also raise NOx's, but something else (CO or HC) should've been raised. Hm. Hey you might want to try adding in "Guaranteed to Pass". It's sold at Pep Boys. First time I used it, my mechanic was amazed at how low my emissions numbers were. Second time I used it, he said it barely passed- then I diagnosed my car as having a leaking injector a few months later. (I still haven't fixed it yet, oops! ) But maybe itll help you out. It's supposed to clean out the catalytic convertor, as well as the injectors/valves/combustion chambers.

Oh, hey, excessive carbon buildup inside a combustion chamber can raise compression. Ever use any cleaner for the throttle body & intake? It's like carb/choke cleaner, in fact, it's sold right next to them, but it's labeled something like "intake cleaner for fuel injected engines". Supposedly using carb/choke cleaner can harm protective coatings on fuel injected motors.

 

my EGR wasnt working properly for almost a year before i got a code...
does it have a MAF? check that! air intake temp sensor? check that...check if its in the right place, and not dirty etc.
usually when you run rich like that and arent getting a code, its because of something with a sensor that might not show up. the code only comes up when something is broken, not when its thrashed ya know?
maybe its abit hard for me to explain....ill tell ya sat.