| BMW Motronic 1.3 | 55 pin ECU to MS DB37 | ||||||||||||
| BOLD are required, others optional | |||||||||||||
| Motronic Pin # | MS Pin # (function) | Wire Color | Description | Notes: | |||||||||
| 1 | 36 (IGN) | Black | Ignition Coil (timing -) Spark A | If using stock coil, jumper Motronic Pins 1 and 6 for simple tach output | |||||||||
| 2 | 7 (GND) | Brown | Ground | GND all sensors at MS. Stock harness has additional grounds to chassis/block. | |||||||||
| 3 | 37 (FP1) | Brown/Green | Fuel Pump Relay (85) | MS pin 37 can trigger both the FP relay and O2 relays | |||||||||
| 4 | 25 (IAC1A) | White/Yellow | Idle Control Valve #3 (open) | IAC1A/B and IAC2A/B pins are normally used for stepper motor, open otherwise. | |||||||||
| 5 | - | Brown | Purge Canister (trigger -) | GND to open - possible to setup a circuit for this, but not neccesary | |||||||||
| 6 | 31(IAC2B) | Black | Tachometer (engine speed out) | JS10 for tach out, no special circuit required for E30 | |||||||||
| 8 | 5 (SP3) | Black | Cylinder ID sensor Signal (pin 1 on E30 CID plug) | Optoin - E36 ODB2 sensor: yellow, signal - red, 5v - black, ground | |||||||||
| 10 | 8 (GND) | Brown | Oxygen Sensor (ground) | GND at MS in order to avoid ground offsets! | |||||||||
| 14 | 9 (GND) | Brown | Ground | ||||||||||
| 15 | - | Grey | Check Engine Light (- triggered) | For information only | |||||||||
| 16 | 32, 33 (INJ-1) | Brown/White | Injectors 1, 3, 5 (- triggered) | ||||||||||
| 17 | 34, 35 (INJ-2 | Brown/Yellow | Injectors 2, 4, 6 (- triggered) | ||||||||||
| 18 | - | Red | Power (direct battery lead +) | Banded end of 1n4001 | |||||||||
| 19 | 10 (GND) | Brown/Orange | Ground | ||||||||||
| 22 | 27 (IAC1B) | White/Green | Idle Control Valve #1 (close) | ||||||||||
| 23 | 37(FP1) | Brown/Green | Oxygen Sensor Relay (85) | Triggered with same pin as Fuel Pump Relay | |||||||||
| 24 | 11 (GND) | Brown | Ground | ||||||||||
| 26 | 12 (GND) | Grey/Blue | Air Mass Sensor #4 | IAT signal | |||||||||
| 27 | Green | Ignition Switch Lead (run position) | Base of 2n2222a | ||||||||||
| 28 | 23 (O2) | Black | Oxygen Sensor (+ read voltage) | ||||||||||
| 29 | - | Black/White | Vehicle Speed input | Future - MS3 supports VSS | |||||||||
| 31 | 6 (SP4) | Yellow | Cylinder ID sensor (pin 2 on E30 CID plug) | +5v - See Motronic pin 8 above. Grounded shield wire (black). | |||||||||
| 32 | - | White/Black | Present Fuel Rate output (to instrument cluster) | MPG gauge requires PWM input - www.seattlecircuit.com | |||||||||
| 33 | 3 (SP1) | - | Spark B | Unused input - I added pins for additional spark outputs | |||||||||
| 34 | 4 (SP2) | - | Spark C | Unused input - see above | |||||||||
| 35 | - | - | - | Unused input - possible to add pins for future use | |||||||||
| 36 | 13 (GND) | Brown | Main Relay (85) | Collector of 2n2222a, 1n4001 | Build a circuit to trigger the main relay | (method 1) | |||||||
| 37 | 28 (12 RAW) | Red/Blue | Main Relay (87 #1) | OR | modify the relay to turn on with the key | (method 2) | |||||||
| 44 | 20 (MAT) | Grey/Violet | Air Mass Sensor #1 | IAT signal | |||||||||
| 45 | 21 (CLT) | Brown/Red | Coolant Temp sensor (not cluster) | ||||||||||
| 47 | 24 (TachIn) | Black | Pulse (engine speed)/Crank Ref Sensor (+) | TACHSEL to VRIN, VROUT to D14, Ignition Capture = Rising Edge | |||||||||
| 48 | 14 (GND) | Yellow | Pulse (engine speed)/Crank Ref Sensor (-) | ||||||||||
| 50 | GND | black/green | IX ABS Com; GND with 1k+ resistor | IX ABS computer expects some sort of signal from ECU, GND with resistor | |||||||||
| 52 | 22 (TPS) | Brown/Blue | Throttle Position Sensor #1 | E36 TPS pin 2 - note, the E30 TPS and E36 TPS have grounds on different wires. | |||||||||
| 53 | 26 (Vref) | Brown/Black | Throttle Position Sensor #3 | E36 TPS pin 3 - be sure to swap E30 tps pin 2 for E36 tps pin 1 | |||||||||