Hi, the engine ran fine for months since i bought it but has recently developed a mighty backfire after having the alternator belt replaced. Part of my investigations in the engine bay brought this thing to my attention. So as the car ran fine before I found it I'll say yes, no issues with the engine and the dial works fine. I don't even know if my YJ has an ECU. It's a Sept 1988 with fuel injection built in Ontario if that helps?