BMW E34 520i 1989, M30 Swap wiring problem, no power for ECU, no start

[peterson98]

Hi !
I swaped my m20b20 E34 with M30 engine. Mechanically its 100% done. (changed brakes, suspension, tranmission, cooling etc)

I have problem with wiring.
Ive moved battery to the rear seat, ground is conected to chasis.
Positive wire goes under the hood, to positive terminal, then to starter, and to two positive wires in e-box (one for ecu, and one for chasis)

Engine harness is conected with the one from the car.

Problem is that the car is cranking but not starting. I cant hear the idle control valve, nothing. (Just like the ecu have no power), engine and the ECU are 100% working (taken from roadworthy car)


Is the "low" version harness from my car compatible with M30 harness ? And if not does anyone have any wiring diagram ?

[cirrusblau]

Try testing your CPS

[peterson98]

Try testing your CPS

Engine is after rebuild and its brand new :/ But shouldnt the idle control valve start working ?

[Goodman’auto]

Hello, i have the same problem on my bmw e34 520i 1989 m20b20… i want to swap m54 on it but i cant match wiring from car to ecu. Btw i have ms43 ecu from e39.
So if anyone can help me… ❣️❣️🙏