ISX cm2250 injectors?

[snailexpress]

Cummins has tool to check each drain line. We have them three connected to drain manifold.
One coming from gear pump, one from safety valve and one from injectors drain passage in the head. The tool is like bungee connector bolt with attached clear tube. So you can check all lines.
Most likely air coming from fuel pump gear pump. Don't tell us it's new. We all know about parts quality.