PORSCHE 911 Carrera MOTRONIC

[E. Decoux]

Hello,

My name is Eric DECOUX (e-mail : eric.decoux at tls.mms.fr)



Fantastic, I can't believe that such a site exist. First, I'd like to 
apologize for my very poor english. I am a frenshie, ... you know I live
in this small country over the ocean.

I own a 911 Carrera 89 whithout catalytic exhaust (231 hp) and of
course, I know it isn't very original, I'd like it to be tuned so to add
some hp.
I bought a Star*chip (England) EPROM but the result is not very
significative, so I have decided to make some personal adjustments in
the engine management data. I have made a dump of the two EPROMs (OEM
and StarChip) and surprisingly only 4 addresses are modified as follow:

Address    Porsche    StarChip
            EPROM      EPROM

#1130        A3  ---->  AB   I think it is the rev limiter (right ?)
#1951        1B  ---->  19   (?) 
#1FFE        01  ---->  00   (?)
#1FFF        08  ---->  B9   (?)

Could anybody give me some explanations about the last three addresses?
I can send the overall content of an EPROM if needed.

I am now trying to learn, in my lab, how this Motronic works. I have
built a small electronic tool which is able to create the sensor signals
(RPM and reference sensors, flow-meter, temp, ...) and simulate the
loads (coil and injectors). I can read on a scope or a PC the injection
durations and relative ignition advance quite easily but I don't success
in correlating my measurements with the EPROM data. I'll need the
addresses of the ignition advance table, injection duration table, RPM
table, temp. coefficients table, ... Could I have some help?

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?
I have noted that very similar patterns are present in the EPROM content
at different addresses. Are they different engine management data? When
are they selected? Is it a relation with the eight positions selector?

I intend to use a hot wire sensor instead of the flap flow-meter. Do you
think that Motronic is flexible enough for such a modification. I think
at first glance that a redistribution of load sites in order to match
the new sensor could be sufficient. If not, a diy-efi will be necessary. 

Thank's for answers.

Eric


PS: Do you have some other tips for such a car?