M50 vs S52 wiring harness

[cbr]

I have a new (to me) S52 engine that will be replacing the M50 motor my 89 325 came with (which was fully functional/running). I'm trying to confirm if I need to redo the harness or not? In digging around I've definitely found some differences between the pinouts (ex oil temp sensor and a couple of others) but I've also read posts from guys who took a M52 motor and swapped it directly into a m50 era e36 chassis.

Anyone an expert on the differences between the harnesses? I'm getting the harness with the S52 motor but if I don't have to muck and can use my existing one I'll obviously save myself a fair amount of time/$$$.

[pazi88]

m50 and s52 engines use completely different sensors and ECU so the wiring harness is not compatible. Of course you could use the m50 sensors, wiring and ECU in s52 but you would need retune the ECU at least. I would modify the s52 wiring harness to fit your e30. it's only matter of swapping the e30 c101 connector to the s52 harness which is pretty easy to do.

[cbr]

Thanks for the confirmation. That's what I was kinda assuming (OBD-I vs OBD-II seems like it would be hard without wiring changes...).

[Northern]

I would go with the OBD2 harness/ECU. There's work involved either way, but end result with OBD2 should be better.