I just got back into town and had a chance to look more carefully through my resources. These pages give some additional insight about adjusting the internal partial load adjusting screws (especially the first two pages). Note the statement "no adjustment is generally provided in the field for this operating mode on Porsche systems" on page 15. It appears that Porsche thought that these adjustments were beyond the capability of most repair shops (and certainly a backyard mechanic) so they never included this information in the Factory Service Manual or CMA. Apparently, Bosch has discussed these adjustments in their technical manuals, especially MFI Pump Test Instructions VDT-WPP 711/1B (ref Section 3.0 Inspection & Repair), but this instruction is next to impossible to find!
© Harold T. Glenn,
Glen's Diesel and Gasoline Fuel-Injection Manual, pages 15-18 (1973).
Posted here for educational purposes only.