BMW 20-pin Diagnostic Socket Pin-Out Diagram

Handy pin-out diagram for the pre-OBD 20-pin round diagnostic connector on 80s and 90s BMWs from PinOutGuides.com [https://pinoutguide.com/CarElectronics/car_diag_pinout.shtml] 

 

1       Engine rotation speed [TD]
2       CAN-High     
3       CAN-Low
4       Shielding
7       Oil service and Inspection reset    
11     External starter turn on
12     Battery indicator
14     Battery power     +12V
15     ISO 9141-2 L Line     
16     Ignition +12V     
17     ISO 9141-2 K Line
18     Programming line [PGSP]
19     Ground [GND]     
20     ISO 9141-2 K Line [TXD]

 

https://pinoutguide.com/CarElectronics/car_diag_pinout.shtml

BMW E30 323i Spec Comparison to contemporary early-80s rivals...

How does the E30 stack up next to its five most common early 1980s stablemates, the MG Montego Turbo, Peugeot 505 GTi, Renault 25 GTX, Saab 900 Turbo and Subaru RX Turbo?

Great review from MOTOR Magazine, November 1985.