Quote Originally Posted by kur4o View Post
The shared ram in 94 pcm is between 1400-16FF and I guess 400-8FF is also in relation with it. There are even some subroutines called at that range.
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I am gathering some pics from different pcms to see what chips GM used as TIO.

While comparing the code between 94-95 and later 96-97 pcm the access of the shared ram seems a little different.

While you are still there can you trace the pins of the knock module. I managed to find that 2 pins are connected to it for 2 different knock sensors, 1 gets 5v and 2 pins goes to tio or some other chip, I can`t interpret my old drawings better. I disassembled the knock module but can`t tell much of it. It looks like the older memcalls. Some ultra small chip and a dozen of condensers.
I think & will confirm when I get a chance, the area just above ram connects to the injector driver circuit (?)

Have you checked to see if the microcode has changed? If yes, the part can be hooked up different and still do the same function. Pins, Addresses or whatever can all be moved.

I will also look at the knock module as part of getting the pinout of tio. This project seems to grow and grow. Very well written and tested code but a mind bender to reverse...

-Tom