1996 Acura Integra GS-R didn't pass CA SMOG today =[
Due to high NO(PPM).

MODS: AEM Short Ram Intake & DC 4-2-1 Header (carb legal)
Stock cat and catback

Mileage: 165k

HC (PPM)
15mph - MEAS: 15 MAX: 61
25mph - MEAS: 22 MAX: 45

CO %
15mph - MEAS: 0.02 MAX: 0.54
25mph - MEAS: 0.41 MAX: 0.53

NO(PPM)
15mph - MEAS: 521 MAX: 467
25mph - MEAS: 400 MAX: 754

I also used a bottle of "Guaranteed to Pass" but wasn't enough to pass the emissions test. I think it may be the o2 sensor I have to replace. Any ideas HT?

 

I have those near exact mods on my del Sol b16a3. My car failed smog even worse than those numbers the first time. I took it across the smog shop to a muffler shop and got the cat changed, passed with 412 at 15 MPH and 73 at 25 MPH. I'd also check your fuel lines or fuel filter, you car may be running too rich or lean.

 

NOx is from high combustion temps. Running lean causes increased NOx. However, running rich increases the HC instead.

Sounds like the cat is on it's way out.

If you don't want to just replace it, you can try dumping ISO Heet into the tank and seeing if it will pass that way. That's what I had to do last time.

 

You could try to back the ignition timing off to 14*BTDC and see if that gets you under. Your CO is low enough that it can stand a little increase and your NOx number isn't too ridiculous. But that would only be a band-aid. Agreed that your cat may be getting old.

 

Oops forgot to check this thread. Got the car smogged and running better than better. Turns out two of my valves were too tight and had a faulty o2 sensor. Got a valve adjustment and replaced with brand new o2 sensor. Passed with flying colors