Car is 1988 Mazda 323 1.6L EFI non-turbo
Just got the car tested under CA Smog 2. Passed. But the 15MPH test was close, with the HC and NO being high. I've replaced the spark plugs, spark plug wires, air filter, PCV valve, rotor, and cap. Have never set the timing though. Is there anything else I can do to reduce the HC and NO? Of course, I'd have no way of measuring an improvement in those areas. So does a car that is optimally tuned always and automatically produce the lowest emissions? Or is it something like the catalytic converter that's wearing out?
January 2004 - engine ignition timing: 07 BTDC
15 MPH Test HC(ppm): 124 Max: 134 Average: 31 CO(%): 0.42 0.82 0.10 NO(ppm): 813 847 237 CO2(%): 14.0 O2(%): 2.2 Tested RPM: 188425 MPH Test HC(ppm): 51 Max: 108 Average: 20 CO(%): 0.38 0.71 0.09 NO(ppm): 228 786 199 CO2(%): 15.1 O2(%): 0.2 Tested RPM: 2946
Here's how the car tested 2 years ago under the old test: (NO not tested under old test)
January 2002 - engine ignition timing: 2 BTDC idle RPM Test HC(ppm): 78 CO(%): 0.05 CO2(%): 8.1 O2(%): 9.0 Tested RPM: 853
2500 RPM Test HC(ppm): 41 CO(%): 0.11 CO2(%): 13.8 O2(%): 1.9 Tested RPM: 2489