Hi John, I just ran into your query. I operate a simjet 3000 and have only just had the xcoy ecu fitted and have not run it yet but I have experienced the same problem when I changed the xcoy ecu for another one. on my TJT 3000. I believe your problem is one of calibration. In the submenu there is a setting for recalibrating the thermocouple. If you set it at ambient then it should follow the full scale. I have forgotten which number it is but if you download the xcoy manual it will tell you: or better still contact the xycoy support web site. Gaspar Espiel is very helpful, or maybe Rob Rowbottom can help, he's a wizz on ecus. The sub menu is accessed by holding down buttons 2 and 4 while you switch on the power to your data terminal. Ron