help with weird engine screeching--89 200q

[LOACESQ@aol.com]

Hi List,

Does anyone have any ideas what is going on with this car?

Background:
For a few days now, my 89 200q has been refusing to start.  The problem
cropped up after I had just finished flushing and changing the coolant
(phosphate free).  The starter cranks fine, but the engine will not fire up.
I have checked all hoses and replaced the suspect ones.  I have checked the
hall sender connector,. ignition coil connector, engine sensors.  Using the
no-start ECU self-diagnostic test, the ECU sometimes gives me codes (2222-bad
pressure sensor, 2342-bad lambda sensor, 2224--overboost, WG pressure) but it
also sometimes gives me 4444--no faults.  In either instance, the car still
won't start.

Occasionally, the engine will fire up briefly, then sputter out.  When it does
run, it emits a horrible screeching whine, like a badly slipping v-belt, but
with a grinding tone.  The noise is not from any of the v-belts.

Any ideas gratefully accepted.

Thanks!

Adam

87 5kcst
89 200q