I tried to breadboard this and the readings seamed strange, so I had a pcb made and I am getting the same issue.
When reading the ADS1118 in Temp mode (Internal reading) I get the proper readings.
However when reading the ADS1118 in ADC mode with a K type thermocouple, It returns 0. If I grab ahold of the thermocouple the value will increase slowly in my hand I can get it to go up to about 12 or 13. If I put a flame on it I can get it to up to around 125 or so. I have read over the data sheet several times. I am wondering if the result I am getting is the difference between the internal temp and the temp reading of the external k type thermocouple. I can post the code if needed, but since I get the proper reading from the internal temp sensor I am not suspecting my code.
On a second note, I cant seem to capture the SPI comms on a propscope, is it just to fast for the propscope ? It cant even catch the cs line going up and down.