CA Smog test

1995 CHEVROLET CAMARO
130,000 MILES • V8 • 2WD • MANUAL
Avatar
OMAR198569
  • MEMBER
  • 12 POSTS
So here's the problem My car is having trouble passing CA smog test. I have taken the car to two different mechanics and they can't figure out why it's not passing the smog test. They both said all emission components are working properly and the last resort was to replace the CAT. The results for the smog test before Replacing the CAT are as follows:
15 mph CO2-12.7, O2-2.9, HC-Max-58 meas-27, CO-max-.48 meas-0, Nox-Max-483 meas-899, Fail;
25 mph CO2-13.6, O2-1.6, HC-Max-34 meas-15,CO-max-.46 meas-.02, NOX- Max-706 meas-225, pass

The results after the CAT replacement are as follows:
15 mph CO2-14.8, O2-0, HC-Max-58 meas-10, CO-Max-.48 meas-0, NOX-max-483 meas-66, pass;
25 mph CO2-14.5, O2-.3, HC-max-34-meas-14, CO-max-.46-meas-0, NOX-max-706-meas-912, fail.

I hope someone can help me.
Jul 7, 2011 at 12:35 AM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.
Advertisement
Avatar
WRENCHTECH
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 20,761 POSTS
It looks like you failed on Nox both times. The catalytic converter isn't going to help that. Nox is caused by too high of combustion temperatures. The #1 cause of high Nox is an inoperative or inadequate EGR system. It can also be engine temp too high, too much carbon build up or ignition timing to far advanced.
Jul 7, 2011 at 12:45 AM
Advertisement
Avatar
OMAR198569
  • MEMBER
  • 12 POSTS
Both Mechanics checked the EGR System and they both said it was working properly. The timing is fine and engine temp seems to be normal. The only thing left to do is removing the carbon build up, what is the easiest way to do that?
Jul 7, 2011 at 4:24 AM
Avatar
HMAC300
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 48,601 POSTS
try this first, change the oil and oil filter, make sure your air filter is clean. drive the car about 15 miles on the eway then take it in to test. this may pass by doing this alone. if that fails GM and Ford delaers have a carbon cleaner ofr purchase that is in a spray can. it's the same stuff .
Jul 9, 2011 at 2:30 PM