I had this very problem. Disconnect the battery. Remove the five amp fuse. Check to see if you have ground on one side of the terminal of the two terminals for the fuse holder. If there’s no continuity to ground, then your MPEM should be OK. If not, you have a bad diode. The signal wire going to the starter solenoid relay could be shorted to ground. Disconnect the plug going to the starter relay. Check for continuity between the two pens on the starter relay. They should be about five ohms resistance. Anything under five ohms can cause a short to ground and pop at 5amp fuse. I don’t have a vts system on mine, but I also heard that can cause a five amp fuse pot to pop. If you isolate the relay by disconnecting that plug and you isolate the VTS system by disconnecting that plug And your fuses don’t pop. Then you know it’s one of the two.
