12-18-08, 03:21 PM
New to the site, living in Colorado. Have a 1991 Brougham which failed emissions for the 3rd time. First test, limit readings for the HC were 1.5000 (mine 2.0829) and for the NOx, it was 3.5000 (mine 3.6992). Second test for the HC it was 1.6200 (mine) - again failed; however, this time the NOx passed (2.9491). Third test, for the HC it was 1.5364 - again failing. After the first test, a tuneup was done. After the second test, a oxygen sensor was added and the timing was adjusted. Now, I'm wondering admidst all of the voices of my "mechanic friends" who feel I need a catalytic converter, if they are right. I'm certainly not a mechanic, just trying to get some advice from some. The car has 176,000 miles on it, runs fine, never failed emissions test till now. One additional note: when last testing for emissions in 2006, the limits for HC were 2.5000 - now the limits are 1.5000 and the limits for the NOx were 6.000 - now the limits are 3.5000 -- Help, anyone!!!
12-19-08, 05:58 PM
A new converter will definately help you with your current situation.
12-28-08, 11:13 PM
Also have someone go through the vacuum lines and look for any split, cracked, or worn hoses. You could have a small vacuum leak, which hasn't affected the idle or ride quality, but is causing a rich running condition, which will throw off the emissions.
12-29-08, 09:25 AM
Make sure you change the fuel filter. that was the problem for me.
01-30-09, 11:28 PM
Thanks for all the help from everyone. Was away from Denver for a few weeks and upon returning,
went through the car, finally replacing the catalytic converter. The car passed with flying colors.
01-31-09, 11:43 AM
Go into your ECC and check your operating temperature and note when (if) the thermostat is opening. Cheap, and easy to change. If the thermostat is sticking open, the engine won't get up to temp and will read high on emissions. Yes, a new cat will clean it up, but the cause of the bad cat needs to be found.