What a racket? It's about the air quality bub. The O2 sensor needs to be fairly hot to do any good (as does the cat convertor). The heating element helps the O2 sensor become useable more quickly.. reducing cold start emissions and fuel consumption. Similarly the quicker the cat warms up, the quicker it can work. The big trick has been for automakers to get all this stuff operational as quickly as possible. I believe "pre-cats" have been somewhat popular (and a somewhat doomed endeavor at least in the case of the Rx-7).

So why should you care? There are a variety of sources that say cold starts are a rather large source of pollution. Volvo's one of them. Someone posted an article to the swedishbricks list about how they've managed to create an emissions system that results in air being more pure at the tailpipe than at the air box.

Don't think car emissions are a big deal? Driven through Southern California recently? They say it's improved....

- alex

'85 244 Turbo