When I go to start the car,my temp gauge will go from 100 to past the max mark,about 3o clock position.

After searching my driver side head has a plug where the sender should be and my pass head has some kind of sensor/sender on it,but it is unplugged.

Why would the gauge move when I start the car but wont go up/down with the temp?

Does anybody know the color wire under the hood that goes to the gauge?

The PO did an engine swap so its a mess under the hood

 

You say the gauge sensor is unplugged.... so where is theconnector? See if its not grounding somewhere else, a grounded coolant temp sensor will read all the way up.

 

I dont know what the connector looks like or the color of the wire. The gauge only reads all the way up when cranking the car. It goes back to 100 when the car is running.

 

I believe it is normal for the gauge to sweep like that on start up, a check to make sure the gauge is operating properly.

 

Mine doesn't sweep like that.