Originally Posted by dhays
I am curious as well. I have had a 6 months of engine trouble, all starting with a problem of my own making. A short recap;
In January I changed the charger on my engine battery and then forgot about that. A couple weeks later when we next ran the boat the engine was running very rough.
Got a mechanic out to check it out. Three visits, a new lift pump, and 6+ weeks later I gave up on that shop (their Cummins Tech was out on an L&I claim).
Called Cummins Northwest, they replaced the fuel pump actuator, all six injectors, and still the problem persisted (the engine simply ran poorly better than it had before). When the mechanic disconnected the alternator and the problem got a bit better, I finally remembered the charger. When it was disconnected the problem disappeared.
Next time we used the boat it ran better than it has ever run, but after a while it would smoke. Still ran well (not as efficient) and no issues with oil pressure or temps.
Mechanic came back Friday and we took it out for a sea trial and he found that one injector was returning a lot more fuel than it should. He corrected that (he thought the tube that feed the fuel into the side of the injector hadn't seated fully) and being as it was late at this point, we called it good. BTW, he along with every other mechanic on the boat checked the oil each time they were on the boat.
Sunday, no smoke, no problems, until the oil pressure dropped.
Excuse my bluntness but you may have incorrectly hooked up the batt charger but I do not see anything you did permanently to the engine "problem".
From your description it appears that a Cummins mechanic replaced parts while guessing at a causal problem and installed one or more parts incorrectly and did not pick it up on a test run.
IMHO - let the problem lay with whomever caused it since this is not a situation that is near resolution and the results may be more than you might imagine - hopefully not - but there is not a complete picture here so far.