Join Date: May 2003
Location: Tinton Falls, NJ
Nox is caused by the heat in the combustion chamber. It has nothing to do with not burning the fuel completely. Is the car overheating at all? Also if your car has EGR, make sure that is working correctly. If your car is not overheating and your EGR is working properly and you still don't pass, then you can try some other tricks to get it to pass, but they won't work if those other 2 things aren't working properly first. If you check it out and everything is working properly and it still doesn't pass, do the following
-Back off the timing a few degrees
-Put in a colder thermostat, the colder you go the more you will cut down nox but the more the HC and CO will go up. If HC and CO are way below the limit now, then try a 160. If HC and CO are pretty close, go for a 180.
-Get the car inspected first thing in the morning when it is still cool outside.
-Make sure there is NOTHING blocking the radiator. The more airflow you get over the rad, the cooler it will run.
Hope that helps.
-91 Cougar LS, coming soon, complete overhaul
with a 427" Windsor.
-90 XR7 5-speed black on black w/sunroof, MP2, coated rotors, double intercooler, 15%OD, ported heads, comp stage 1 cam, 85mm TB, 90MM LMAF, 80# injectors, and ported big valve heads
-98 Mark VIII LSC, Procharger P600b, TR3650 swap and 3.73s.
-90 SC Automatic rustbucket winter beater
-97 Tbird Sport 4.6 Nice weather daily driver
-"Your buddy Mike is INSANE!" -ClintD's dad