In Reply to: Passing CA Emissions posted by Eric Fowler on March 03, 2000 at 11:20:26:
As far as your cats go, they can usually tell if they are working by putting a temp probe on them. If they are working, they achieve a certain temp. Don't know the exact temp, but do know that the catalytic reation is exothermic (i.e gives off heat).
Other than that, look at what you were exceeding.
Too much fuel could cause excess HC. This could be leaky injectors, etc. I also hear that O2 sensors are always good to replace if they have miles on them. Definitely don't purchase these from a dealer. Even if you have a dealer install them, you can supply the parts.
However, if you are that much over the limit, I'm not sure if a basic tune up is going to get you where you need to go. A good independent shop that deals in BMWs may be the ticket. I found dealers were not that great with the 12 cyl cars.