911 Carrera Motronic

[Eric DECOUX]

Hi Jim,
Thank you for your answer.


You wrote:

>>#1951        1B  ---->  19   (?) (I think you mean 1941)

>  A singular spark advance datapoint, being retarded           


  I fear the content of my EPROM (911 Carrera 3.2 MY89 european spec
whithout catalytic exhaust) is slightly different from yours.
  Please find hereafter a hex dump of mine starting from the address
01900h.

$A1900,
32 32 32 32 3E 0C 02 01 08 08 08 08 15 1B 0D 19 
0C 6A 4F 0C 05 07 06 06 07 0D 0D 0C 0D 1A 1A 5F 
25 25 25 25 25 25 25 25 20 1A 1A 1A 1D 1D 1D 23 
2B 2E 25 1D 16 12 12 12 19 19 19 19 1C 1E 21 1D 
16 12 12 12 19 19 19 1A 1D 20 23 24 1C 1B 1B 1B 
19 1B 1C 1E 21 25 2A 27 23 21 21 21 1B 1B 1F 22 
25 2A 2C 2A 25 21 25 25 38 3C 43 43 43 43 2F 2B 
28 24 2A 2C 38 3C 45 45 45 45 38 31 2F 2F 31 36 

$A1980,
43 48 4E 50 50 4E 45 3E 3A 3A 3A 3A 48 48 4E 50 
50 4F 45 3F 38 38 38 38 48 48 4E 4E 4E 4E 45 3A 
32 32 32 32 48 48 4E 4E 4E 4E 40 32 32 32 32 32 
3E 10 02 01 01 01 01 01 10 08 1F 19 14 12 07 05 
05 65 12 12 12 12 12 12 12 21 27 37 3A 36 32 33 
32 31 3E 0A 05 02 02 10 06 06 03 19 19 9C 20 25 
1B 19 19 1B 23 23 3F 48 2C 03 8D 1A 4F 25 14 14 
2C 03 10 3C 9A 1A 1A 14 2C 06 18 18 1D 31 0C 6C 

  As you can see, address #1951 corresponds to the value 1B
  which has been changed to 19 in the Starchip EPROM. 
  This EPROM is supposed to improve (??!) a bit the engine
  performance, so I suppose this value is relative to
  an ignition advance increase at WOT.

  Please, could you give me just an info: how many load 
  and RPM sites are used for ignition/injection mapping?
  What are the RPM values?


> YUP .. the Fuel Quality Switch..    
  What is the position of the switch which correspond to the best
  fuel quality?


About my Motronic learning method
>WHY are you trying to reverse this so bad.. it takes YEARS, and the only
>2 guys I know who have done it.. Myself and Todd Knighton!     
I'll say that for the moment and without any precise entry point in the
EPROM content, it is the only solution I have, but may be it will change
thanks to the info collected on the web. 


>>I have some other questions about the EPROM content. In such a Motronic,
>>does the EPROM content only management data or data + the controller
>>program?

> Program also.. it's all in there!!
Sorry but are you sure that all the pgm is in EPROM? Why using a 8051
(controler+EPROM) instead of a 8031 (controler only) in such a case. 
Furthermore, but may be I am not right, I think that the 8051 wiring in
the Motronic allows it to access to its internal EPROM. So the Reset and
Interuptions vectors (which are useful for pgm disasembling) should be 
located there.  


>The whole Vafm to Q (airflow/mass) conversion is done in some tables
>in the Motronic .. if you had flowcharts of Q vs. V for both the flapper
>and the Hot FILM (do NOT use hot WIRE!) sensor, I could help you redo the
>tables.. they are NOT the same tables that you see ..     
  What are from your experience the drawbacks of the hot wire 
  sensor compared to the hot film? Anyway, I think that a hot
  wire sensor is far more easy to find as a second hand part. 


Read you soon.
Bye and happy new year.
Eric