Motronics 1.0 Help

[dfh]

I am trying to modify a 1984 Bosch Motronics 1.0 unit - the one with the
RCA 1802 processor and the soldered in ROMS (4 of them!). It seems at
least one company offers a modification package to add on a removeable ROM
to this system. 

Does anyone have a circuit diagram or other information on how to modify this
thing? I have actually gotten the binary code from a Porshe enthusiast, and
started to decompile it. I was also able to find a 1802 assembler, so I'm
all set to modify the code - just not sure how to get a new ROM into this
thing. (I'd migrate to a Motronics 1.1 if I didn't have to change a raft of
stuff in my 84 BMW to get it to work correctly.)

David Hoerl
dfh at superlink.net

PS: anyone know what a Siemens "BB 0127" chip is? Its used in the ECU off
the temperature sensor - must be a voltage-to-freq converter or similar...