Originally Posted by gasman6674
The diesel systems are triggered by engine load (vacumn)
Most of what you said is correct. Except for that statement. Diesels don't have manifold vacuum. If they do, it's extremely low.
Originally Posted by EPNCSU2006
A diesel engine has no throttle and is capable of ingesting how ever much air can be crammed into the cylinders,
And that is why. Unless the air filter is plugged, there is no restriction to air flow into the cylinder and therefore little or no vacuum.