These are on the block and i've always wondered what they were. The one on the right side was never hooked up when i got the car if its something that needs to be hooked up. i have an 82 280zx with an 83 turbo motor. thanks

 

freeze plugs. So if the coolant in the block gets cold enough to actually freeze, they pop out instead of expanding the block and cracking it...

or do you mean the knock sensor? i'm not exactly positive what you want us to look at...

 

i know what the freeze plugs are lol i just didnt know what the coolant plug was at first and the sensor on the other side had no wires coming out of it so i had no idea what it was but now i know its a knock sensor.

 

all blocks have that plug, the knock sensor is on every turbo car. you should have 2 wires by your CHTS that would plug into those. Also, it all functions fine if it isn't plugged in, and if it was, and there was knock detected, the ignition timing just gets retarded I believe

 

pic 2 is the oil pressure sending unit...

 

Pic one is the coolant plug for the block.

 

the oil pressure sending unit is on the other side of the oil filter.