Plug and play wiring for megasquirt 3

Hello everyone,

My project is a BMW e36 320i with an m50b20TU and I have decided to use megasquirt 3 due to it's price range, now that i have the ECU I will need to wire it and my question is how can I do so. I am fully dedicated that I will do it myself even though I'm getting an offer to have the connector made for 100 bucks.

What I need is a connector which will adapt from the stock wiring harness into the ms3.

The stock ECU on the car is a Siemens ms40.1

Any help will be greatly appreciated!

Pinout for ms40.1: https://support.haltech.com/portal/en/kb/articles/m50-engine (the exact pinout is found at the bottom of the page for my engine)

Pinout for MS3: (attached in the photos)

How about getting Bimmer ECU from the scrapper and use the ECU connectors to wire in your custom loom to MS3? MS3 in photos diagram look really like Molex connectors if I'm not mistaking. These shouldn't be hard to obtain.

Yup ive already done that basically ill be keeping my stock harness and ill use the connector from the junker ecu which will then go into the ms3 question is how do i wire it up which pins to what.

for instance how would i wire the injectors and ignition coils?

Would i wire every injector on a different pin from 1 through 6 and then same goes for the ignition coils?

If you'll be using sequential injection and direct spark then yes there will be one output per injector, and one per coil.

Have you verified the triggering system you are using supports this?

You have the pin-out of original ECU right? You have pin-out of MS3 right. You now know what pin should be connected to ECU and vice versa when you use stock wiring. Maybe start with a Spreadsheet with couple of columns; Orig. ECU Pins/ MS3 pins/ Wire color & AWG.

I'm pretty sure it's sequential injection and direct spark yes