Wiring Harness Apapters

[Literary]

I'm in need of well-functioning wiring harness adapters for the following two applications:

(1) A 1995 S50 from an M3 going into a 1991 e30 318is cabrio.
(2) A 1988 M30b35 from a 635CSi going into a 1991 318i sedan.

I didn't know if anyone either had either of these or were able to fabricate them for me.

Thank you.

- Peter

[Jean]

Literary - regarding (2)... mention what engine harness you plan on using with the b35. there are quite a few different ones out there, e24/e28/e32/e34/e30 rectangular connector, round connector with 20 pins, round connector with 25 pins.

[gregslow318i]

just got your email and just sent one back to you. I think I can help you.

[Literary]

Literary - regarding (2)... mention what engine harness you plan on using with the b35. there are quite a few different ones out there, e24/e28/e32/e34/e30 rectangular connector, round connector with 20 pins, round connector with 25 pins.

Am I incorrect in assuming that the "best" wiring harness, at least to begin from, would be the exact one designed for the donor car -- the 1988 635 CSi? Among my concerns would be the potential for a accurately "chipping" the engine.

[Jean]

I wouldn't say it's the "best" one, take for example my example of using a 91 b35 harness with an x25 connector, wouldn't even fit into late model e30 cars like the older harness with a 20 pin. What does the 635csi connector look like, is it round 20 pin or rectangular like the e28s? (rectangular e28 c101 is also different from the e30 rectangular c101 fwiw).

Chipping the engine won't have anything to do with the harness, it's not done through the harness like on obd2 cars..

[Literary]

Ah! Thank you for that information!!

It seems, then, that I have a wide-open field from which to choose. My 635CSi wiring harness has been compromised (i.e., mangled and cut from the previous owner), and the computer, I've now discovered, is defunct. So as I say, it seems I can start from fresh.

Given the different options you mention above, is there a particular combination you would suggest? It seems, again, that I have some freedom of choice in the matter.

Greg has suggested go with a straightforward M20 set-up. Are there any advantages to trying something else (at least from your list)?

[Jean]

If late model 318i(s) c101 is anything like the m20 (you'll need to confirm this), then going with a harness with a 20 pin round c101 is the way to go imho. With m20 harness you'll have to extend some wires from what I've read vs going with a e34 535i harness for example. Just keep in mind some e34/e32 harnesses have 20 pin and some have 25 pin connectors when you shop for one.

The e32/e34 harness looks cleaner as it hides a lot of wiring near the manifold/head where the fuel injectors are.

Greg can make you an adapter :)

[gregslow318i]

jean is right when it come to m30 harness and most if not all harness is that first they are built for that car with that motor from the factory. when you are doing a swap m30/m50/ls1 etc you need to ether 1 build your own harness or 2 modify a factory one to fit your car. point being you can use just about any harness of the same or similar motor family (m20's on m30's or m50's on m/s5x etc) only main thing that should be taken into account when doing this is the tune ie "correct chip" for your combo. in your case you are using your stock ecu with a stock motor but not necessarily the "stock" harness. in layman's terms a harness is just a bundle of wires that are between the dme and the motor the shape really does not mater if the dme can be tune with it (not such a problem with the motroic stuff but the ford ecc now that's a different story.) kinda a 6.5 and a half a dozen from ether point of view