Engine is a stock '91 TII w/Mazda ECU, FCD, custom FMIC, Bosch 61975 fuel pump,
80mm DP, 3" exhaust. The air tube for the CAT is temporarily blocked (no CATs).
It currently has a new [stock] Hitachi turbo on it, and pulls ~10 # max boost.
In general, it runs like a scalded cat, starts at first twist of the key, hot or
cold. No evidence of anything out of the ordinary, except it smokes after long
periods of idle.

The following have been eliminated through debug:

• turbo, turbo seals and more turbos... $$$
  
• tweaked turbo oil flow down to .040" using clear drain tube
  (did someone install a high volume oil pump?)
  
• disconnected hoses for oil purge valve and vent after AFM
  
• block OMP oil lines & OMP air lines (oil is pre-mixed)
  
• passes "5000 rpm decel. test"
  
• EGT is in range...
  
• AFR @ ~15 MPH: 14.95
  
• using Autometer electric fuel pressure gauge,
  • line pressure, fail: 42 PSI, spec: 34.1-39.8
    (when key is turned off pressure drops to 39)
    
  • hold pressure, pass: 34 PSI, spec: > 18

Is 2 PSI over on fuel pressure at idle going to cause these kind of problems?
The car doesn't seem rich at idle, it doesn't make your eyes water. I
assume if it's going rich enough to wash down oil (one of my theories...), it
would have to be seriously rich! I can get an AFR reading at idle to eliminate
that mystery... I would replace the fuel pressure regulator with an aftermarket
one, but the S5 fuel rail has the FPR attached.

When I was debugging turbos and seals, the turbos were dry on the engine side
and soaked on the turbine side. That's why I thought this was all a turbo oil
supply problem.

In it's current state, there is no path I know of from oil galley to intake.

I'm hoping that another set of eyes can see something I missed...

Thanks