Missing sensor?

[rybo760]

Hey zilvia still workin on my project car
it starts now (finally) the ignition switch was bad haha "doh"

but now i have atleast 3-4 plugs on my engine harness that i cant figure out where they go.

the most obvious one is one that should plug into a sensor or something that comes out of the front of the intake manifold under the Coolant Temp Sensor.

PICTURE IS NOT MINE!!! NOT MY ENGINE IM USING IT AS AN EXAMPLE I DO NOT OWN OR HAVE EVER SEEN THIS ENGINE.

I took this picture from yoinkAzenki (http://zilvia.net/f/members/yoinkazenki.html) for sale thread for an example.


Now if you look at the coolant temp sensors, right under them there is a plug sticking out.Can anybody tell me what it is?
http://i27.photobucket.com/albums/c183/D3liciousRyan/samplepicture.jpg

[projectRDM]

Knock sensor. There's a subharness that plugs into the sensor body that runs up to the front of the engine. The engine harness then plugs into it.