My personal preference with new nozzles is to disassemble them and wash with a strong solvent like lacquer thinner. They're shipped with an oil to protect them and it can screw up things during your pop calibration. Dip both parts in clean diesel and gently reassemble before putting in the holder and assembling the finished injector. Remember that the injector nozzles are precision machined parts, don't mix and match pieces, keep them as matched sets.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]