1991 Chevy Camaro Oil temp

The ECM gets the oil temp. Reading from a sensor on the back of the motor by the firewall.

It could be that your computer is reading (39-degrees Celsius) That would be about 100-degrees Fahrenheit. Which is still too low.

Either way (if it's reading -39 F, or 39 C), it's probably forcing your engine to run in "Open-Loop". That will definitely make your engine run rich.

In case you don't know the difference:
"Open-Loop" is a condition the computer uses when the vehicle first starts, and hasn't warmed up yet. The sensors can't measure correct values until the engine has had an opportunity to reach its normal temperature. So the computer disregards most sensor data and uses a pre-determined set of programs to run your motor until it has reached the right temp. Then it will go into "Closed-Loop", and begin to read and respond to all of the various sensors.

If your oil/engine temp isn't reaching the proper temp, or the sensors are bad and feeding the computer false information, then it will continue to operate in "Open-Loop". That will definitely cause a rich condition.