At 10:19 AM 4/17/2015, Chris Szpejankowski wrote:
>I tested an empty cat on my '84 Westy. The DJ code engine liked it.
>No O2 sensor use by ECU in that one and I only used it monitor fuel
>mixture. I noted a slight change in sound. I could not tell or smell
>the difference otherwise.

My California-spec '84 Westy was delivered in Germany and spent its
first seven years with no cat or O2 sensor.  VWOA supplied and
installed them when it came to the States in '92.  They were a bit
unhappy afterward because the sales agreement only specified such
within three years of delivery, but I asked for it and got it fair and square.

If the engine is otherwise correct the sensor does nothing to improve
operation; it only sets up the mixture so the CAT has balanced
amounts of reactants to process in its three-stage reaction.

Yours,
David