I was looking for an affordable way to get cylinder head temperatures into my Haltech R3 ECU. Haltech offers a CAN bus method, but it's quite expensive for just one input. Instead, I found the Adafruit Analog K-Type Thermocouple Amplifier - AD8495 Breakout, which you can purchase on eBay, Amazon, and other retailers. For the 14mm spark plug thermocouple, I bought one from a Canadian company, Thermomart.
https://www.thermomart.com/cylinder-head-temperature-gauge?search=14mm
I put together some wiring to test it out, and it worked! You need voltage, sensor ground, and input.
I still need to do some calibration. With the engine off and cold, the intake air and CTS should show the same values - and I think I better charge my battery.
