84 Riviera 307, what's this sensor?

Dont' have a pic but it's a round yellow and black plastic piece screwed into the front drivers side in the intake manifold. Has a 2 wires coming out from the top, I think 1 is black and 1 yellow. Pretty sure it's not the temp sensor, this one is plastic not metal. Yellow on the bottom half and black on the top, kind of looks like a little spaceship.
Anyone know what this is for? The sensor end of the wires on mine are getting a bit worn/frayed and look like they could break off at any time.

 

If you could get a pic of it, it would be helpful.

 

If it goes into the threaded hole that now has a pipe plug , it is the coolant temperature sensor for the ecm. The sender to the left is for the temperature gauge. If it still has the old style sensor and connector, the type of connector that has to be squeezed on two side to unplug, I don't believe that you can get those anymore. You will need to replace the sensor and connector with new style. That style sensor hasn't been used since probably 85 or 86. Those sensors wound actually leak coolant through them and the connector and the ecm would end up with coolant inside..

 

If this is the front of the manifold, I think it might be located where the brass plug is now in that pic. It it round plastic and is black on the top and yellow on the bottom and has some black lettering on the yellow part. I will have to take pic's later on today.

 

Found a pic on the web finally! Hope this works. Hard to see in most engine pic's since it's so buried, unless it's a junkyard car
It's the piece on the front next to the water pump opening that's black on top and yellow on the bottom and has wires coming out the top.

https://www.thetruthaboutcars.com/w...-Arizona-junkyard-photo-by-Murilee-Martin.jpg

 

That is the coolant temperature sensor for the ecm. The white part is the retainer for the connector. You squeeze the white retainer and pull up to unplug the sensor. If the wires or the sensor are bad, it gets replaced with an updated version. You must replace the sensor and the pigtail with the new style. I don't think that you can get the old style sensor or connector anymore. There were lots of problems with tho old style.

 

Thx. for the info. What do you do if the wires are becoming fragile/exposed at the connection to the sensor? Also, what would happen if it was not working?

 

If the wires are bare,just replace the sensor and pigtail. The pigtail has the connector and usually 8-10" of wire, along with crimp connectors. Assuming that the car is still running the ccc carburetor, if the wires touch each other, you'll get a check engine lite and a trouble code 14, and the ecm will command the mc solenoid lean. If the wires are broken, you'll get a code 15 and the ecm will command the mc solenoid rich. Of course, if you are no longer running the ccc carb, you can either leave the sensor in (if it's not leaking) or install a pipe plug in the manifold..

 

That is the correct connector for the replacement, new style sensor.If he still has the old style sensor, which hasn't been available for 30+ years and he needs the connector or the sensor, both will need to be replaced.

 

Still have everything original, CCC and all. Does the new sensor come with the wires/pigtail or do you have to get it separately? Nothing happening yet with regard to the check engine light, so I guess it's OK for now. Just have to watch when I'm cleaning the engine not to bump into those wires