I bought a 1991 convertible I bought it as a turbo2 swap halfway complete. Ive gotten everything I need to put it together and have it mostly put back together. I can' find anything about the pressure sensor in all the places Ive looked. It is a small black sensor on the side of the ecu. My na ecu doesn' have it so I would assume it is a turbo part there is nothing on the harness for it. Do I need a turbo2 wiring harness can I make my na harness work? I would like to have it ready for drift season. If anyone more knowlegable on rotary engines can I help me I would be appreciative.

 

Scroll to the bottom of this page: 86-92 Engine Electrical Turbo Boost Sensor is what I believe your looking for. It's on the passenger side strut tower I believe. Check there if you're lucky the PO already changed it. From my research you should be able to make the n/a harness work. There is a thread I posted in around here somewhere that covers it.

 

By the ECU is atmo pressure sensor.....atleast in S4
Not sure if S5 does have it, probably not.......