Mercury - Race Engine ACI Harness Performance Gauge Link 892486K04. OverviewThis Race Engine ACI harness gives performance rigs a clean, direct way to feed key gauge info from the PCM. It uses the 3-pin link to deliver data for oil pressure, coolant temp, fuel pressure, oil temp, and tach-exactly what you want to see on a high-output setup. Out on the water, it keeps those readings steady and includes transient-voltage protection to help shield the PCM. It's built for race engines using a Vessel