1995 Chevy Camaro smog test

OMAR95

MEMBER
1995 CHEVROLET CAMARO

Engine Performance problem
1995 Chevy Camaro V8 Two Wheel Drive Manual

I took my car to get smogged 2 times the first time it failed really bad because the catalytic converter and EGR were bad so I replaced them and gave the car a tune up. The second time it passed the 15 mph but failed the 25 mph test. It failed because the NOx was a bit high but like I said I have already replaced the EGR and the catalytic converter so I don't know what else I should check. If you could help me I would appreciate it. Here are the last smog reading. This is a CA smog test.
15mph %CO2=14.8, %O2 =.2, HC(PPM)= 22, CO(%)=0, NOx(PPM)= 689 it passed them all.

25mph %CO2=14.7, %O2=.3, HC(PPM)=14, CO(%)=0, NOx(PPM)=840 it did not pass, the max for the NOx is 706

1 Reply

RACEFAN966

MECHANIC
5,029 POSTS

Well lucky for you I use to do smog in that state so I first have a few questions. Did you make sure the gap in the plugs were correct? Did you check the timing to make sure it was correct? What was the temp of the car at the time of the test (was it fully warmed up). Do you have a digital multi meter so we can check the coolant temp sensor and the O2 sensor? When you say you gave it a tune up what all did you replace as it seems that everyone has there own idea of what a tune up is. Also how old is the fuel filter? Get back to me and we will go from there.