Diesel injector leak-off ?

[nujon]

Still learning about C/R diesels - would someone please explain:-

• what is injector leak-off?
• why does it occur?
• what is normal vs abnormal leak-off
• what causes abnormal leak-off?
• what are the affects of abnormal leak-off?
• how is abnormal leak-off cured?

 

[nujon]

Done a 'home-made' leak-off test - diverting the flow from the un-plugged leak-off connector to a vessel (shorts glass) and surrounding the solenoid with kitchen towel - then starting the engine - virtually zero leak-off from 1,2 and 4 over 30secs but 3 outflowing but only slightly - visual judgement (rightly or wrongly) is that no 3 not yet in need of changing (I accept that there are specific volumetric leak-off criteria per rpm but I don't have the kit to do that)