MEMCAL swap '88 to '89 (identical cars)

["Shawn R. Lin" <slin01@mail.orion.org>]

My girlfriend and I both drive Oldsmobile Cutlass Supreme
Internationals.
Hers an '88, and mine is an '89.  Both have 2.8L V6's, both have 1227727
ECMs.
Where they differ, is her car used to be mass air.  It has a cylindrical
airbox and a MAF.  However, a sticker on the core support states that
the car was upgraded to Speed Density and to consult the 1987-88 Speed
Density supplement for more info.  Her car also has California
Emissions.  Her ECM is VERY touchy.  If power is temporarily removed
from the ECM, the car will refuse to start for 50-100 cranks.  Once it
starts, it wants to die, and it is difficult to even get the car to stay
running in Drive long enough to complete the standard idle relearn
procedure.  The idle relearn procedure also must be followed TO THE
LETTER or else it will stall and die at every stop.  Once the idle
relearn procedure is properly done, the car is usually fine but still
dies occasionally the first half hour or so.  After awhile of driving,
the car is fine from thereafter.  However, I flushed the cooling system
today and there was some accidental splashing of coolant.  After I shut
the car off, I let it sit for an hour or so.  Splashed coolant seems to
have totally messed up the car's electrical system, as it no longer
wants to run.  It acts as though the battery was disconnected.  I
suppose resetting the ECM and doing the idle relearn MIGHT fix it, but
this is pretty much the last straw.  I remember one time, all I did was
clean the carbon out of the throttle body.  The car ran terrible and
never recovered on its own.  I had to reset the ECM and go through idle
relearn again.  The car has given us so much grief and frustration.

On the other hand, my '89 has a square plastic airbox, no MAF, just an
IAT in the airbox.  Other than that, everything is virtually identical. 
However, my car seems to have a much better set of base parameters.  If
power is temporarily disconnected, the car will still start right up
first try and seem to run perfectly from the start.  Even if idle
relearn procedure is ignored, it will still seem to run just fine.  I
have also once cleaned out the TB on this car too, and not once did it
stall.  It was a little trembly at idle, but after awhile, it fixed
itself.  This car has Federal Emissions.

I have a spare MEMCAL from my '89.  I have been hypothesizing that her
car may run better with an '89 MEMCAL.  I plan to go to the library
tomorrow to compare the two ECM schematics to see if there are any
differences in wiring that may pose a problem.  I think VSS, MAP, O2,
IAC, EGR, and other various sensors/controls are the same.  Only problem
will be that her MAF functions as an IAT, while the '89 has a real
standalone IAT.  Will this pose a problem?
My goal is to make her car's ECM as "robust" and easy to live with as my
'89.
Any thoughts?

-- 
Shawn Lin
http://www2.cybercities.com/g/gmwbodycars/
__________________________________________
NetZero - Defenders of the Free World
Get your FREE Internet Access and Email at
http://www.netzero.net/download/index.html
----------------------------------------------------------------------------
To unsubscribe from gmecm, send "unsubscribe gmecm" (without the quotes)
in the body of a message (not the subject) to majordomo@lists.diy-efi.org