lordkenmore
Well-known member
I don't have the knowledge to comment about emmision systems, regulations, etc...
That said, it's been my understanding that the catalytic converter needs to be hot to work. Years back, I had to take a very marginal car in for my state's emission test. A mechanic basically said to drive it a long distance to get everything warmed up. And then go to the testing station. If I had to wait at the station, he said keep the engine running, and keep your foot on the gas to have the RPMs above idle--other wise, you run the risk of the catalytic converter cooling enough to fail the test. I did that last thing, even though the wait wasn't long, and the tester was cranky, asking if the engine could idle at the usual speed. If not, it was an automatic fail. I said yes, but it was going to idle this fast while waiting for you to do the test. The car--even though it was a falling apart wreck with nearly 300,000 miles--passed with amazingly good numbers.
Another tip the mechanic had: go in early in the day if possible. Apparently, there have been some test failures due to tailpipe sensing equipment getting dirty during the day.
Of course, I think on newer vehicles they test by connecting to the vehicles computer. The last car I took in--the one I mentioned above--was too old, and since that time, I've moved over the line to an area where testing is not needed.
That said, it's been my understanding that the catalytic converter needs to be hot to work. Years back, I had to take a very marginal car in for my state's emission test. A mechanic basically said to drive it a long distance to get everything warmed up. And then go to the testing station. If I had to wait at the station, he said keep the engine running, and keep your foot on the gas to have the RPMs above idle--other wise, you run the risk of the catalytic converter cooling enough to fail the test. I did that last thing, even though the wait wasn't long, and the tester was cranky, asking if the engine could idle at the usual speed. If not, it was an automatic fail. I said yes, but it was going to idle this fast while waiting for you to do the test. The car--even though it was a falling apart wreck with nearly 300,000 miles--passed with amazingly good numbers.
Another tip the mechanic had: go in early in the day if possible. Apparently, there have been some test failures due to tailpipe sensing equipment getting dirty during the day.
Of course, I think on newer vehicles they test by connecting to the vehicles computer. The last car I took in--the one I mentioned above--was too old, and since that time, I've moved over the line to an area where testing is not needed.