late 95+ ECU performance (on turbo Talon & Eclipse)

[RABBITT_Andrew at mv8.orbeng.com.au]

>Apparently, early 95's, which sport a visibly different ECU board (=> 
>different ECU code?), don't have the problem. 

the new ECU is probably more powerful to cope with OBDII requirements

>The problem is that when the boost pressure is raised by as little as 
>1psi above factory nominal, the engine suffers from an abrupt power 
>loss due to major timing retard.

probably a strategy to protect itself from an overboost condition.  
It's obviously not been calibrated at that level of boost, therefore 
destruction by knock is a real possibility, hence the 'major timing 
retard'

>Assuming that the 2nd O2 sensor is in place to let the ECU know that 
the cat's doing its job,

correct!

>and that going WOT removes careful stoich control on the mixture, 
>then the engine's gonna tend rich (like in the 1st gen's) to handle 
>the big air coming in. The high volume of rich exhaust will cause an 
>apparent degradation in cat performance, which the ECU will detect.

I would guess that at WOT, the controller goes open loop and therefore 
ignores the signals from both oxygen sensors.  You can only detect 
catalyst performance with two oxygen sensors working together, and 
then only closed-loop and stoich. 

>We could insert a divide-by circuit between the knock sensor & the 
>ECU to reduce the number of pings sensed by a jumper-programmable 
>factor.

not sure what type of signal you're expecting from a (presumably 
wide-band) knock sensor, but it 'aint sound like it would work