Update: Turbo seems good. turbine side is nice and tight with no play in the shaft and the fins all look good, and it spins freely. Compressor side has just a touch of play in it, but doesn't seem to rub on the housing, and again the fins are all good and it turns freely. also i did the ghetto turbo test, and it passed (see here:
http://www.youtube.com/watch?v=jOGYIsAizQU )
while i had the up-pipe (?) off, i did the "bench test" of the O2 sensor even though it was still in the car, and have determined that it is bad. i have a new one on the way from the parts store right now, and hopefully i should have the turbo and throttle body back on by the time it gets here. had to order an O2 socket as well, because there is no way to get the sensor out without one that i can determine.
still haven't got a fuel pressure gauge extension yet, but hopefully the O2 will get me on the right track without having to deal with that.
Also, If i understand correctly there is overboost protection... and my factory boost gauge is wildly inaccurate. it's more like an "are you touching the throttle" gauge. with only part throttle it jumps up to 15lbs of boost in under 2 seconds. (add on gauge never reads above 0...)
this is entirely based on speculation, but here's my theory:
factory boost gauge reads 15lbs, so overboost protection kicks in (i assume it activates the wastegate solenoid and just dumps all the boost, but i guess it could cut spark, timing, or fuel...) which is what is causing it to bog when it should be taking off like a rocket. so i guess my questions are:
1) is there overboost protection on an 85, or is it just on the 86-87 with the better ecm?
2) what is the factory boost guage getting it's reading from? MAP sensor i assume...
3) what, if it even exists, does overboost protection do to get the boost back to a safe level
4) am i even on the right track in assuming that this could be causing my symptoms?