My car is consistently failing smog, I now have it passing on HC and CO, but it still fails on the NOX. Not just by a little either, the readings are almost 2000 and u need to be below 800. My setup is z6 block, y8 head, obd-0 91 si ecu, obd-0 si dizzy, new cap, new rotor, new 9.3 mm wires, and bosch +2 platinum plugs. Could the cat be causing such a high NOX #, it is about the only thing I havent changed yet. Please any advice is greatly appreciated.

 

this all so new to alot of us with the new dyno testing..have u had ur car diagnoist as to what the problem is?

 

I have not had it diagnosed yet, that costs 60 roughly and was looking to fix it myself. I searched all over the web, but most sites when talking about NOX only mentioned problems with EGR(exhaust gas return) I have no problem with my EGR being that there was never an EGR on my car.

 

ttt

 

NOX from what i understand is caused by high compression. To reduce the NOX output from the exhaust is to get a new cat. I heard of a guy runing high compression and had a mustang 5.0 cat on his honda and it passed.


[Modified by Creamies, 9:09 PM 3/10/2003]

 

Thanks Creamie, I just put a new cat on today so we shall see, a little off topic, but can 2 cats one after the other significantly help?

 

two good condition cats isnt a bad idea if you dont pass with one......dont just add another after the old shitty one though, that will help, but exhaust flow will be significantly impared around the cat-region...i just went to pep-boys and bought the biggest cat i could find in the back......2.5 inch like my exhaust, and my car passed on the third try.....the guy just tried a few times, he missed a shift once, so he said that failed it......silly illinois dude's not knowin how to drive a stiff cable clutch

 

Thanks for the help guys, Im going in tomorrow with the new cat...

 

good luck let me know how you did, im intrested if that was enough to gget it passed.

 

OMG the focker passed!!!!! With the new cat it barely burped out any HC, CO, and NOX at all. Im so happy!