Quote Originally Posted by lpugh View Post
I can see very well how that could happen with a air injector stuck open, during the combustion process a lot of pressure is developed that would feed back into the air rails thru the open direct injector, spiking air pressure enough to reduce fuel/air pressure spread thus reducing fuel flow from another injector at the moment of the increased air pressure, I doubt the tracker valve and pressure regulators would be able to compensate for that completely. A pressure wave from the combustion process is pretty intense, think of 2 cycle expansion chambers and how they function, pressures and timing of the pulses
Just theory on this is, not a fact
Any thoughts on that Merc guys ?
One of many methods in which a Direct Injector that is not closing properly/timely can result in cascading failures of adjacent DI's and/or cylinders.

Quite simply: Combustion event needs to remain in the CYLINDER. If the DI is not closing between pulse events, those hot combustion gases (best case) are passing back into the rail. What happens then is never good.