you need an e36 m50 diagram nas. not an e21 one.
print the relevent one off, nas. i found it invaluable wiring my m20 turd up.
look at the engine diagram. i believe its the "x20" plug of the engine loom that goes to the car loom. you need to wire it up to the e21 fuse box. picking out the wires for stuff like;
starter solenoid wire,
alternator exciter wire,
temp guage,
oil pressure,
revcounter pick up,
fuel pump live.... etc etc.
look on the e36 diagrams for these wires and find out the pin numbers/colours at the x20 plug.
on my e21 fuse box wiring these are the colours and what they do;
on the e21 loom i had these pins:
3x green/violet..... ing lives..... wire to bits on the carb.
2x big greens...... ing lives...... 1 of which was live side of e21 coil.
2x blacks...... one went to coil neg, one went to the tci unit.
2x blues...... ing lives...... alternator.
1x brown/green....... ing live...... oil light switch.
1x brown white.......... water temp.
- ing. feed to the coil - green/violet
- starter solenoid - big black
- rev counter - smaller black (different pin to starter wire)
- alternator exc. - solid blue
- oil light switch - brown/green
- water temp. - brown/white
dont take these as gospel, check it out first!!!!