I think its the oxgen sensor Ill try to look tomorrow to be sure. I just installed my engine runs great but Iam having trouble with Metering Oil Pump.

Good Luck

 

it's unused...i got freaked out too when i saw it.

https://www.rx7club.com/forum/showth...hreadid=126620

 

Its only for t2s and automatics, used to actuate an extra electric fan up front. Dont ask me why only those models got the option. Same on s4's: on teh AL thermo neck, some had a sensor there, some just had a blank hole.

 

I also noticed that connector on my 90 GXL when I replaced the engine last summer. Also, if you look at the bottom of your extention manifold, you'll see two plugs that resemble freeze plugs. These plugs were used for the sub-zero starting system. Later manifolds did away with these plugs. To answer your question, I believe that connector was used for the sub-zero starting system solenoid, which Mazda did away with in some locations. I'm pretty sure that Canadian model RX7s kept the sub-zero starting system.

Hot_Dog
90 RX7 GXL
02 RSX-S

 

that is the flux capacitor hookup. there is a pretty sweet one in the for sale section right now.