Exact location of ECU ground?

[britandy]

Does anyone know the exact location of the ECU ground on a 7.4L MPI MIE L29 GEN VI equipped engine, as found in my 2000 MY 340 Sundancer. I know there are two ground wires on the back of the engine on a single stud, I think one is the ground from the battery, is the other one the ECU ground? If not I assume it has to be on one of the ground bus bars? I have looked at the wiring diagram as found in the Mercruiser Service Manual page 4E-17 which shows a single ground just below the illustration of the ECU but of course does not list its location.

I know ultimately I can start to pin test, check continuity, trace the wiring but if someone has correctly identified the ground before it would save some time!

Thanks, Andy

 

[scoflaw]

It grounds to the engine stud as you mentioned. What issue are you having ?

 

[britandy]

scoflaw, I have another thread going on the issue, the one titled "Engine ECU swap for diagnostic purposes?" You have already passed on some good suggestions on that thread. I am still not sure if the issue is solved, I have not had a chance to really test the boat out since having the injectors cleaned/tested and then reinstalled. I just wanted to make sure I have identified the correct ground for the ECU so as to rule that out.

I do plan on an overnight trip in the boat tomorrow so she will get a good run.

 

[scoflaw]

If it happens again disconnect the tack like mentioned