I have a 85 735i that I recently did a head job on. The car has been sitting for a while. I have replaced some of the injectors that were leaknig and the cold start valve and the fuel pressure regulator. Cats are lees than a year old. Replaced idle air solenoid a year ago. Cars runs and performs okay. Went to get it inspected and it failed for High Nox.
Readings are below. What can I do the get the Nox down ? I have not had the Air/Fuel ratio checked at the exhaust mainifold after the head job. Could this help ?
Pollutant Reading Standard
HC 110 152
Co% .70 .97
CO2% 13.4 N/A
Nox 1582 1082 FAIL
Dilution 14.1 >6