I have read that. Not sure about it.
don't you trust the information given by Bosch or my information given below?
I own some - not all - informations given by Bosch concerning the measurements / testing specific engines / car models with the EFAW228 in original, provided by Bosch- no reprint or so. But only in German.
Some of these workshop-manuals contain this information, others don't.
The informations given for Mercedes are:
- engine M114 (250): 2000 rpm, max. 1 Volts differing
- engines M116 (350, M117 (450): 2000rpm, max. 1.5 Volts differing
- don't own the manual for M110 (280). But the Opel-manual (R6, 2800, same trigger-unit as Mercedes) notes 2000 rpm, max. 1 Volt differing.
The Voltage information is not given in the manual that remarks '3 markings' or '2 markings' on the scale instead. But these markings are every 0.5 Volts, therefore this is equivalent to 1.5 Volts / 1 Volt.
I don't know if or where the manuals are downloadable. They are marketed by Bosch even nowadays, have a look: Kundendienstanleitung: BOSCH D-Jetronic in MERCEDES-BENZ R107, W107, W108, W109, W111, W116 - D-Jetronic - Werkstatt-Literatur
Graham, the manual for the V8 consists of 3 parts. I only own one of them, the part with the direct testing information.
Contact me via PM if you are interested in this subpart.