I'm dealing with a no start / no crank on a 90' 240 Wagon AT . It's a bit of a humbling situation to say the least… Forgive the long post…

BACKSTORY:
Last week when I Started it seemed to struggle I little (slow crank) I notice the volt gauge stayed down at the 12.5 start up level voltage until revved the engine, then jumped up to normal 14.5v reading. I have had a few of these 'slow crank, then starts' in the last few months. The car drove fine and voltage stay up at 14.5 for the 3 mile trip, 45 minutes later went to start got maybe 3 slow cranks and then a few clicks from starter, then nothing…

WHAT I'VE DONE RECENTLY:
- timing belt
- water pump
- Radiator (crack at upper hose flange during T-belt swap)
- New Shifter bushings
- Odometer gear
- neutral safety switch
- Most recent: Just days before I installed a 52mm tach from a 84' 240.

WHAT I'VE TRIED:
- Jumper neutral safety switch
- Cleaned battery terminals
- Checked Plugs
- jumped battery
- replaced battery
- Jumped from remote start switch to battery
- Jumped from remote start switch to Starter
- Jumped from Battery to Starter
- Check and cleaned starter connections
- Pulled alternator, voltage regulator brushes borderline 5mm (ordered replacement)
- Disconnected AMM
- Hand crank to check from cam movement (t-belt)
- Checked and cleaned 25a fuse
- Checked and cleaned grounds: Main (to block), fender-wall, Alternator, power steering, gray firewall.

QUESTIONS:
- With the fault code unit socket 6 I get a constant light on? Is this indicating that I have a short somewhere in the ignition? I know the unit at least halfway works because I get a 1-1-1 reading from socket 2.
- All but my SRS dash lights stay on. SRS lights seems to go off intermediately?
- Could a bad crank position sensor cause this type of problem? Where is it? Is there anyway to test it? Seems to be absent from the Bentley book?
- Do I simply have a bad starter?

Thanks guys,
- Oscar