Question: wiring alternator and starter

[FredK]

I searched for info on wiring the alternator and starter, and it seems like 1990m3 had a lot of the same questions that I did. His thread really solved most of all of my questions. However, one or two remain.

In the following picture, I know that wire A goes to the starter's main lug, as does the wire from the alternator. Wire B has the same sized ring as wire A. Does that go to the starter as well?

Thanks in advance for your help! This harness is a spare; the actual harness is in the car already.

Keywords for later search: power wiring, alternator, starter, blue wire, red wire, fat lug

[tonytony]

which one is wire B? the one from the harness or the one coming out of nowhere? the alternator wire and wire A both go onto the starter, my power wire from the m50 harness was cut by the PO so had just used the stock e30 power cable from the isolation block, everyting works fine.

If wire B is the smaller red wire, i believe that goes to the fuse box on the e36, the e30 already has power going to it from the isolation block

[FredK]

Thanks Tony. Wire B is the second red wire that comes out of the harness.

Let me edit the pic to make it a little more clear. Wire C is the wire that's coming from the alternator. So A+B+C all go to the large lug on the starter?

[tonytony]

only A and C go to the starter, B is supposedly goes to the e36 fuse box.

[FredK]

Well, B is a positive wire; if it doesn't hook up to either the starter or alternator, where does it hook up? TIA!

[1990m3]

try hooking it up at the power block on the passenger side of the engine bay. It's been a year since I looked at the wiring, but I think one of those power wires had to be routed back through the harness to the power block on the e30. Not 100% on this, but close.

[tonytony]

to make thigns easier, i suggest using the e30 power wire. Yank the power cable out of the harness and use the stock single e30 power wire going to the starter. You dont have to mess with wire B

[FredK]

Thanks for the feedback guys! There is a large diameter power cord on the other side of the wiring box already, and I'm gonna crimp the E30 power wire connector onto it.

[skatebline]

Ok soo if the big e30 cable is connected to the starter i can just rip out the other red cables from the harness and the engine should turn over'???

[FredK]

Yep.

I actually just ripped out the large red power cable that splits into two cables in the harness box and used the E30 starter cable.

[skatebline]

Yep.

I actually just ripped out the large red power cable that splits into two cables in the harness box and used the E30 starter cable.

Ok sweet deal, but just earlier today i tried to see if it was long enough and it wasnt.....do i need to make it longer, or do i run it down behind the engine?

[tonytony]

Ok sweet deal, but just earlier today i tried to see if it was long enough and it wasnt.....do i need to make it longer, or do i run it down behind the engine?

yes

[skatebline]

alright ill hook that up when i get time.

[Jason89i]

Yep.

I actually just ripped out the large red power cable that splits into two cables in the harness box and used the E30 starter cable.

dont forget to hook up the alternator too. factory uses the one wire off the power block, splits it.....one to starter, one to alternator. I have seen some e36's with a single power to the starter and then the same size jumper from starter to alternator.

cheers, jason

[FredK]

Yep, my wiring arrangement was to remove the E36 split power wire and use the E30 starter wire.

I also had a large jumper wire that went from the starter hot lug to the hot on the alternator. This is the arrangement that I've seen so far on 2 E36s--a 94 325i and a 1/95+ M3.