ok i have a question on 90 ls motor on the back of the block they are three sensor's what are they. on the 94 motor there is only one sensor the other two are blocked in. one of them you can screw off but the other one is completely sealed. i am using the wiring harness of the b18a1 and the intake manifold of the same. But i can't figure out what they are. I think the one that is screwed in and can be screwed out is some kind of oil temp. sensor i think the one that is sealed is something to do with the coolent*sp temp. on the old motor there is no sensor on the termostat housing but on the b18b1 there is one sensor on the housing could that be the same as the one on the b18a1 block?

 

The 1 pronged threaded sensor is oil pressure

The 2 pronged threaded sensor is water/coolent temp

Plug style connector is a p/s pressure switch sensor.