Wiring hook up help

[Beau B]

Alright well I was a dumb ass and ripped my S50 out of my car before taking pictures of everything and it has been a while since I put one of these motors in. Anyways, can some one help me and tell me where these wires go? This is a 92 non-vanos 2.5 The harness is also a little different. Thanks for the help.





This is what I was thinking..
A - Power Block
B - Ground
C - Ground
D - Starter
E - ??

The last picture is of a wire left over from the M20 engine where does that go?

Beau

[PeaveyBassist]

Pretty sure you're right for A-D. Not sure about E though.

Will

[BDSax]

e may go to the starter also, but im not sure.

[joshh]

edit since I was only partially right....

[FredK]

I am doing this part of the swap right now.

A goes to the positive block. In the middle of cable A, it splits up into two cables, D and E.

In the E36, D goes to the starter, E goes to the fuse box. However, on the E30, the fuse box already gets power with a different cable. So, you can put D and E on the starter's large 10mm lug.

I chose to remove this wire (A, with D and E as terminations) and use the E30 power wire, which is your last, unlabeled picture. It has the proper lug to attach to the main power cable, has the proper terminations for the fuse box power leads.

HTH,
Fred

[Mike B.]

Fred is spot on.

[Beau B]

Thanks Fred, that was a huge help! I think I am going to just remove the e36 starter wires and use the M20 one like you said. Thanks again.

Just to clarify though B and C are both grounds than?

Beau

[FredK]

Read Mike B's post below.

[Mike B.]

B goes to the distribution block and C goes to the ground on the shock tower.

IIRC, if you pull back the black cover on C, the wire will be brown.

[FredK]

Thanks Mike!

I should have known! On the 95 M3 harness I have, one of the cables has a piece of red heat shrink on it, but not on the 93 325i harness that I'm using for the swap.

So do you hook up B to the power block where the fusible link goes (6mm post next to the large power cable)?

[Beau B]

Good to know, hopefully when I get to the shop tonight it will start no problems :)

Beau

[Mike B.]

Yep, B goes to the 6mm post.

[FredK]

Thanks!

[EtaSport]

A+B go to Battery power. You need to get a battery terminal type connector and cut off the Big red ring and attach it to the big battery terminal right at the distribution block.

C is a ground (the longer wire). Its easy to double check, cut back the black cover and one is brown (ground) and the other are red (power)

*I thought the 6mm post was the fusible link power wire, and C should go straight to a ground. I've wired two e30m50s this way*

The other side of the big red one goes to the starter, that smaller red wire is redundant (its supposed to power the fuse block on an e36)

The big black wire goes to the starter.

this is exactly how I wired mine two weeks ago.

[FredK]

Oops, I think we got a little mixed up here. Mike originally said

B goes to the distribution block and C goes to the ground on the shock tower

which is exactly what you said EtaSport. I confused things and asked the wrong question. The wire that is paired with the diagnostic connector should be grounded (C) at the shock tower. Wire B goes to the distribution block at the 6mm post that the fusible link is connected to.

I changed my post. Mike, if you can update your reply, that would help future swappers wire up their power. Hopefully Beau B ignored my post, and his car hasn't gone up in flames in the mean time. :D