I'm in California, got a 91 740 wagon with Regina engine, 260K miles.
I just passed the smog test, but only barely for the NO at 15mph. Max is 785, I got 781. When he revved it up for the 25mph test, NO dropped to 518. I had just driven the car for 25 minutes or more on the freeway before the test.
I got a new cat converter 4 years ago. He said they usually last about that long. That doesn't seem right.
So, how long do cat converters last, on average?
New ones (manufacturer) are required to last 100,000mi. 4 Years sounds like they're trying to sell you one. They can become less effective if the engine is burning oil or dumps unburnt fuel into the exhaust. The whole point of a catalyst is that it's not used up in the reaction.
Bill
Mine had been leaking oil for quite a while, but not burning out the tailpipe. The flame guard got plugged and blew some seals recently. Got all that fixed. I wonder if all the times I ran low on oil created fumes that got to the cat converter.
That oil leak problem is fixed now, thankfully, now that I've found a decent mechanic.
Will my recent slower driving improve or hurt my emissions?
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