> Doesn't really matter because when the governor opens the rack on all those pumps the scrolls open to dump in more fuel.

The governor "opens the rack", but a pump fires only when it is operated by a cam lobe (this has to do with generating the injection pressure, which is considerable). On the other hand, if the rack opens too far, then all the jerk pumps will put out too much fuel as they fire. As mentioned before, excessive black smoke is usually a sign of turbo lag. Decades ago the SP "solved the problem of turbo lag" in its U-whatevers by changing the control circuits so that when the throttle was moved to run 1, engine rpms went to run 4, and when it was placed in run 5, they went to run 8. This eliminated turbo lag for run 2, 3, 5, 7, 8, and 9 so it produced only a few puffs of black smoke.

EMD engines are subject to turbo lag too, usually in the form of "turbo burps" which are caused by the overrunning clutch catching briefly, slowing it down. This produces a sharp, loud noise and reduces the air/fuel mixture, which results in a puff of black smoke out the stack.