'89 E30 S14B23 M3 no spark DME Teardown Assist.

[aviator]

I'm getting real close to tearing into my 35 pin DME because of a no spark issue. I am almost done checking everything else: coil, wires, Crank sensor, Speed sensor, all pertinent relays, all continuity's, all power, almost everything that feeds into or goes out of the DME. One interesting test that shows that I don't have a completely dead DME is one where 4pins of the DME connect directly to the AirFlowMeter connector, and all of those voltages at that 4pin connector (actually 5-pin but one unused) confirm to be correct. That is, with the ignition in the on position I do get 12V into the DME (pin18&35), and I get 4.3V, 10millivolt, 5V, and 0V at pins 9,7,6,22 respectively of the DME connector. At this point I sense that if there are voltage regulators in the DME, then I am getting an appropriate 12V to 5V step down because of a 5V signal coming out of the DME. This means that one or more of the IC's are either powered from 5V, or I might be getting fooled that the IC's are 12V tolerant and simply provide 5V outputs only. And my being fooled is because I don't have an internal schematic to the DME. I'm real interested to understand the power transistor at pin 1 internal to the DME because of its' critical function to switching the (-) side of the coil to ground, hence allowing the primary side to charge up, and then collapse when disconnected from ground.

Does anyone have a schematic to a Motronic Basic (1.0). I read that if I have a 20 pin diagnostic port, which I do, then I have a 1.1, but my diagnostic port is for the M3 and has 7 pins empty. I'm finding the M3 has subtle differences than most of the other E30's so I'm leaning more heavily toward mine being 1.0 because the S14B23 was essentially unchanged from 1987-1991. I'm the original owner and the electrical is as from the factory. I understand there is a rebuild service too, at Pelican which I'm interested in getting more information on, but I can diagnose a lot more if I had a schematic to the internal of the Motronic Basic DME. Anyone know where I can get a schematic. It's definitely not in the online 134 page BMW electrical troubleshooting manual.