The middle wire is bare ,that one doesn't show on the drawing,does it have to go to ground.This is the sensor from Isspro kit

Normally, yes a bare wire is made for ground.

I used ground in my setup but it was bit difficult to get hooked up solid. Look closely at the instructions it will show it.

My ground doesn't go in the middle, it goes on the outside to the far right for my pyro. I used a small flat screwdriver to push the ground into the harness and left the black instal tool in place.

I tied mine to tight I can't get to my plug on my gauge. Thanks for the pic.

Thanks for the pic! I was done the installation before the pic ,I didn't hook it up to the connector and it seems to read the temperature ok,maybe we don't need it like my pic shows...thanks again guys,next is the exhaust and intake.