You are correct, the catalytic converter cannot affect the NOx level. You probably need a tune-up including cleaning the fuel injectors. I would check the timing and make sure the mechanical AND vacuum advance are working. Also you should use fresh gasoline of at least 91 octane when you go for the test. Don't go on old, stale, low octane gas, it mattters. Some of the additives are very volitile and evaporate out if the gas is old so you should either burn it off or drain and refill with fresh. Change the air filter too. You don't say how many miles are on the car. You should check the Lambda circuit to be sure it is functioning properly, you might need a new O2 sensor. After you tune it up you should drive it a little before going for the test to burn up all the HC remaining in the converter. David Teitelbaum vin 10757 --- In dmcnews@xxxxxxxxxxxxxxx, "rendycheng" <rendycheng@xxxx> wrote: > Hi > > I just have a smog check done and my D failed. I am located in California. This test was > done at "test only" center, and the car was put on dyno. The test results are as follows: > > RPM=2292 (at 15mph) > HC_MAX = 141 HC_GP=331 HC_MEAS = 161 > NOX_MAX = 1148 NOX_GP = 2270 NOX_MEAS = 2211 > > To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/