I just failed emissions with my 92 CamaroRS - 305 TBI... here is the results:

HC limit - 1.20 gpm my result - 0.31 - PASS
CO limit - 20.00 gpm my result - 1.15 - PASS
NOx limit 3.00 gpm my result 4.57 - FAIL

Any suggestions to get the NOx down? I am swapping motors in March to a 350, but the inspection is expired now. Just want to get it to pass so I can drive it / keep it on the street

Thanks!

 

When was the last time you maintenced the ignition system? Also does your air pump still work. The air pump should help lower your NOX emissions.
A high nox means that you are burning too hot. Bad carbon buildup in the combustion chamber can also cause this. If that is the case i would just write the EPA and tell them that you lost the engine and are putting in a new one in a couple months. I know you wont be able to drive the car but dealing with the carbon buildup is not worth it.

 

Air pump doesn't do much for NOx, that's mostly for HC's. The EGR valve lowers NOx. Clean the passageways out, or buy a new one if that doesn't work.

 

The igition system is fairly new.. MSD 6AL box, with msd cap / rotor, coil and superconductor wires. The EGR valve was replaced when I swapped manifolds, approx 6 months ago. Is there a quick fix I can try to get it to run a little cooler.. retard timing a little, etc?..

 

Don't cats also reduce the NOx?

 

High NOx.......check the following:

-Engine overheating
-Lean air/fuel mixtures
-Vacuum leaks (can cause lean mixtures)
-Overadvanced timing
-Defective EGR

 

i've seen stuff called all-u-need, pour it in the tank. they guarantee you pass emissions or double your cash back. costs ~$6.

 

What!? Where do you get it and does it work?

-Matt

 

i think it's made by bardahl, i got mine from Murray's Discount Auto. I've used it on two cars and both passed but they may have passed without it too so i dont know if it works.