04 200 HPDI New power head install keeps blowing fuses

[Jwlamberton]

I recently swapped out a blown power head on a 200 hpdi. When I got everything installed the 20 amp fuse for the fuel pump and ECU keeps blowing. I unplugged all harness connections and plugged in just the ECM connections. With only the ECM connected the fuse blew. Checked the blown fuse an had 12 v on one side about 10 v on the other. Could anyone help me come up with where this back voltage is coming from. Thanks.

[boats.net]

Look for pinched or chaffed wires shorted out in wire harness.