Still have a major rich r= unning problem.  My original description of the
problem is attached.  Since that posting, I have tested the Temp II= sensor
over its entire operating range and it falls nicely in the curve shown i= n
Bentley.  Also went through all the other resistance checks shown i= n Bently
(mostly at the ECU connector plug, which is where I also took my Temp II=
sensor resistance measurements).  Everything is right on the money.= I have
triple (at least) checked my connections and grounds.  I checked fo= r any
blockage on the fresh air intake.  No restrictions.  Revving t= he egine in
neutral yields thick black smoke.  I observed that blipping the tho= ttle
quickly but to wide open throttle causes the AFM to snap fully open, of
course, momentarily.  Anybody ever take notice of this?  

I have been told of other cases where all tests of the fuel injection sy= stem
are positive and the problem being cured by replacement of the F/I wirin= g
harness.  Has anyone ever heard of or experienced this?  VERY = expensive thing
to replace without being positive that its the culprit.

Will have the exhaust gas analyzed this week in hope that it will point = to
the problem.  Hopes for long-planned Memorial Day weekend vacation = are slowly
dieing.....


ORIGINAL MESSAGE

My '84 GL is running very rich.  Mileage is 10 mpg at best.  Blows t= hick
black smoke when loaded (i.e. under acceleration).  Down on power in g= eneral.
 Idle speed is eratic but does not stall (yet?).  Been driving her d= aily
under these conditions for months.
Things I've done:
Checked/adjusted ignition timing.  Was retarded.  Now correct (at le= ast
close).  Made no difference.
Measured fuel pressure:  36 psi at idle with vacuum connected.  42 p= si (at
any engine speed) with vacuum line disconnected.  If increase engine s= peed
(with vac. connected), fuel pressure decreases (yes, DECREASES) to about= 32
psi.
Swapped out the air flow meter for another (used but serviceable) one. =  No
significant change in behavior.
Examined the spark plugs.  All four were equally black and sooty.
I also cleaned (with electrical contact cleaner and, in case of ground
connections, emery cloth) and exercised all of the connections I could f= ind
on the engine management wiring harness.
I plan to measure the Temp. II sensor resistance tomorrow.
An observation:  I noticed that the position of the AFM wiper is about= 20 or
25% "open" with the engine idling.  This seemed surprisingly high to m= e, but
I have no reference.  Could be normal.  Anyone have any input?  I = also
adjusted the CO adjustment screw (under the plug on the AFM housing) and= this
had no real effect on the position of the AFM wiper.  Had a small effe= ct on
the quality of the idle.

I did a mechanical rebuild on this engine two years ago (did not do anyt= hing
to the fuel injection/engine management system).  It ran fine and gave= me 19+
mpg overall fuel mileage until this problem cropped up a couple months a= go.