sblax2000

Ok, I need some help because my car would not pass smog. The NO levels were above the acceptable level, around 715 for the 15 MPH test however it did pass the 25 MPH test. Any ideas as to what could be causing the excess amount of NO?

I currently have a CAI and y-pipe, and the car was warm during the test. The car has been having some trouble starting up and has been idling high. I reset the idle lower last week, but it has bounced back and now rests between 1K and 1.5K. I recently did the 120K tuneup a few hundred miles back.

Thanks for the suggestions

the_3d_man

iTrader: (1)

NOx is caused by running too lean. Maybe an O2 sensor...?

sblax2000

Also, the shop said that the check engine light was on, but when I went to check it, I got the 0505 clear code. The car is getting really good gas mileage.(30MPG) last trip.

Mishmosh

iTrader: (3)

Most of the time, low NOx is mostly dependant on a properly functioning EGR system. 700's means it is at least partially working. Maybe time to clean the EGR guide tube.

DR-Max

iTrader: (3)

My car passed smog even with a bad EGR solenoid valve and my ECU was throwing that code. All I did was clear the CEL light before driving to DMV for registration.

I'm not sure what is causing you to fail smog. This is why I would never put a y-pipe in my car (for a mere 10-15 hp) especially having a cali-spec Maxima. Hope someone else can help you on this. If all else fails, swap the stock y-pipe in until you pass.

Vlasic

iTrader: (13)

Your NOx is also controlled by your cat. If you have a bad cat your nox will be really high. When I went in for smog about a year ago my nox was 900 something. I got a new cat and I passed with like 500 something.

UncleMax98

Also check for intake leak. If you remove the intake to clean the trhottle body, check those clamps. I almost failed NOx a couple of years ago due to a loose clamp.

Supermax95

iTrader: (2)

i have a calispec and passed with a y-pipe, b-pipe and catback....

Black Maxima

Werd........