Hi All, I need electronics schematic for this ecm, I am going to open it up and see if I can find the problem with NO communication. Any ideas to start with?. I have 2 of them that have been tested by obd2 and told #1 couldnt communicate. #2 couldnt communicate. So I have nothing to lose cuz these are junk i'm told. i will have them back in a day or two and will post numbers if that will help. The first one did nothing in the boat,no relays,pump, nothing. The second one when turn key to run fuel pump and ignition relays work and fuel pump comes on for seconds and will run while cranking but no spark or injector action. There is power to both but the ecm grounds to operate from what i understand. The ecm gets signal from ignition sensor and knows when to fire injector. This is 5.7efi basically same as gm 5.7 tbi without o2 sensor or crankshaft pos sensor, gets rpm from dist sensor. These mefi3 are delphi and are nla so only choice is used if find one. They are 2300new and 1400 used. i was going to give repairing it a shot, I have a feeling my client hooked up battery backwards and that fried ecm cuz I found blown 90 amp also.