Anybody know what kind of generic Bosch 4-wire oxysensor I should use to
upgrade my 1984 one-wire? Seems to me that the voltage-to-ECU output should
be exactly the same as stock, and resistance for the heating element should
be low enough not to blow fuses. Are the threads all alike?

Hmm, maybe this is a question for a list vendor...

My 1.9 runs on the cold side, and it took 12 minutes of city driving to kick
into closed loop mode yesterday. The water pump and thermostat are near new,
and it does get up to operating temp, just takes a while. During which time,
mega gas uusage.