My last boat (Maxum 2800 SCR) had a 7.4 MPI motor, which has the MEFI3 ECM. I looked high and low for an easy means to obtain the engine data for my NMEA 2000 network. The answer was this product: https://fox-marine.com/index.php?route=product/category&path=81 It was a breeze to install and the inventor is very knowledgeable and helpful if you have problems (I didn't, but spoke to him before purchasing). Once installed, all the digital engine data is available on your NMEA 2000 gauge or MFD, including fuel flow, temp, oil pressure, etc. etc. etc. All the about 2004- engines usually output to vessel view or the Volvo equivalent. If you want to get into the digital age with your old 7.4 MPI, check this product out.