'94 & '95 LT1 Ecms

[Ken Kelly]

Chad,
	The stock 8051 has multiple tables for the transmission.
You shift between them with the performance switch. This
switch is on some F-bodies, but not all. The code to use the
switch is in every 8051 I have seen, including Impala SS and
Caprice Cop Cars. 

	This swich only works on the Xmisiion tables. You would
have to modify the code to use this function with the fuel
and Ignition tables. There is blank space in the Flash, so a
good programmer should be able to accomplish what you want,
but it won't be easy.

	The 8051 is Flash style memory. There are two processors
and two 512K Flash chips. They are early Flash chips that
have no block erase commands. You must erase the entire
chip, and get it reprogrammed before you shut off the PCM or
you just made a nice door stop.


		Ken

ChadBeebe at eaton.com wrote:
> 
> I just found the GM ECM web site and have read through alot of
> the archived messages and would like some clarification of
> what I have read specifically on the LT1 ecms.
> 
> What I have understood is that these ecms are a flash style,
> meaning I have to erase the program and then dump a new
> program in.  I am also interested in the memory address for
> the fuel and spark tables.  The main question I have is, is
> there enough free space in memory to have multiple tables
> that get used say if a certain switch is set?  I was thinking
> this might be a way to have a fuel/spark table for economy
> and another one for performance.
> 
> Also where can I find the software to write to these chips,
> and does it work through the ALDL connector.
> 
> Chad Beebe
> '97 T/A WS6 with '95 computer.