Miata Mailing List: October 1999, Message #52

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> Hi!  This may be a dumb question, but are all A/F meters the
> same?  Meaning, they aren't picky about what O2 sensor they are wired to?

The A/F meter only talks to the ECU, not the O2 sensor directly. The ECU use
the A/F signal and O2 signal to choose fuel and ignition settings... I think
you can get most Mazda A/F meters to work with the stock ECU, but I really
don't know much about it. Note that the '94+ cars use a 'hot wire', and not
an A/F meter.

> WRT O2 sensors, am I right in saying that no Miata ever came with a 4 wire
> O2 sensor?

No, all 1.8 engines have the 4 wire sensor, at least the US cars does.

Espen