Guten Abend,
I hope y'all aren't sick of Das Boot and me, yet.   I have the Bentley out again tonight and have been testing the connector for the Digifant unit. 

Bentley   section 24.61  Electrical testing, ignition and injection system

Test 1---terminals  13 and 14,  14 and 19----ECU voltage supply--OK@13volts          

Test 2---terminals 13 and 25---wire to ignition coil's terminal 1----------
          Bentley calls for a minimum of 8 volts with the ignition on.
  I tested at LESS THAN 4 VOLTS.  Could this be the culprit??   

Test 3------wire from starter terminal 50 and from adapter for the idle stabilizer control unit terminal 50---------ON HOLD.

Test 4--------terminals 3 and 13 bridged------fuel pump and relay tested OK

The test prerequisites called for by the Bentley are:
Battery OK
Fuel pump and relay OK
Idle stabilizer control unit OK

My idle stabilizer control unit is known to be faulty.  I have had it pulled out for over two years.   
After getting the 3.5 volt reading on Test 2 the first time, I said what the heck and plugged the ISCU back in and tested.  I got the same 3.5 volts.

Is a bad ISCU causing the low voltage or is the ISCU prerequisite for Test 3 only. Do you think I have found a bad wire
and maybe the source of my problem?

Assuming I have found the bad wire to the coil(I have no spark at the coil,)  where  do I start tracing?  I have the Bentley, and thus,  the schematics but I have had a difficult time using them in the past.  Any shortcuts would be helpful.
Hoping and testing,
Dan Hall
86 Westy
Alabama