Finally found some time to pull the injectors and remove the nozzles/ pin/ shims / springs etc for an ultrasonic bath in 99% IPA for about 30 minutes each, followed by soaking in diesel before reassembly + new copper washers. Tip for others, I found hot glueing some scotch brite to the end of a 3/8" extension a good way to clean up the injector seats in the head.


I put my borescope down the injector holes for a quick look, and found what looks to be possible pitting on the cylinder wall closest to the injector in cylinder 6. Maybe an artefact of the incomplete combustion?


For reference the before cleaning warm values:
Cyl 1: -0.8 mg/stroke
Cyl 5: -0.8 mg/stroke
Cyl 3: 0.1 mg/stroke
Cyl 6: 5.0 mg/stroke
Cyl 2: -0.6 mg/stroke
Cyl 4: -3.2 mg/stroke


And note, I switched the physical injectors around after cleaning to see if the worst offenders (cyl 6) move with the injector or stayed with the cylinder.
Before injector # / After injector #
1 / 6
2 / 4
3 / 3
4 / 5
5 / 2
6 / 1

And after cleaning values (drove for about 10 minutes):


Cyl 1: -0.9 mg/stroke
Cyl 5: -1.5 mg/stroke
Cyl 3: 1.2 mg/stroke
Cyl 6: 1.1 mg/stroke
Cyl 2: 0.3 mg/stroke
Cyl 4: -0.1 mg/stroke Which all seems pretty reasonable, however I am a little concerned by what I think I saw down the cylinder 6 - but surely if I had compression issues here it would show up in these correctional values right? Had me extra concerned as at first start up after cleaning the value for cyl 6 was still quite high even though it was a different injector, but that seemed to settle after driving.

Keen to hear any thoughts.