Ej20G v1 02 sensor?

[asotwavb]

Hello i own a 1992 Legacy SS with a first generation Legacy RS swap running on the EJ22t harness and PCM.

When i purchased the car last year, i first noticed the car doesn't have any o2 sensor. I get fairly decent mileage (20MPG) and the car runs real strong at 10PSI.

Do these engines require 02 sensors? I figure they must....

A little more background:

5-speed
No CEL
440cc injectors
WAIC
3 inch exhaust
Aftermarket intake

Thank you for any help, searching hasnt come up with much.

-Will

[Legacy777]

Hi Will,

Yes there should be an O2 sensor. I don't know if the ECU pin out is going to be the same between the two ECU's. These older ECU's sometimes will run ok without the O2 sensors since they run in open loop a lot.

[asotwavb]

Thanks Legacy77! I will have to take a closer look when i take the car out of storage for the winter. Maybe that could be why the car is intermittently sluggish at times. Regardless, i have a wideband that will be installed.

Once again, thanks!

[Legacy777]

You're welcome.

When you put the wideband in, you would probably find it running rather rich....which may be a result of the ECU not seeing an O2 sensor and/or it staying in open loop most of the time.

[asotwavb]

Better rich than lean, i suppose

Once i head down to get the car out of storage ill find out whats up with the factory 02 sensor, and wire one in.