Thank you for swift help Diesel Wrench :-)
Now that I now that also the lift-pump lust get the max. Alternator-chargin voltage during running of the engine i know what to hunt for.
So i will go and hunt from approx. Wednesday on this "whatever-source-of-voltage-drop"
Thank you indeed Diesel Wrench. Have a nice weekend
Meanwhile i found "the answer to my desires" >
Engh Motors - USB-to-ALDL Interface Cable
I have just yesterday placed a order.
Then I will install a Laptop as "Boardcomputer" and then I will have great fun learning this Software and technology, reading out all the sensors.
What I will do as well is checking all the ground's; the one going from the Batt. - to tha Chassis (just below the cooler) i redid already, the next at the back end of the motor i found already, the others i will need to search for.