M20 starter has 3 terminals, s50 starter has 4

[Lof8]

I'm using the m20 flywheel/clutch/starter



so, wheres the extra wire go?
thanks

[Mako18]

The extra wire goes on the 10mm post (I think that is what size it was). You obviously know where the power wire goes. Also your about 30min drive from me. I know a few local e30 guys that wanna go for a cruise I'll pm you when that gets closer.

[Lof8]

The extra wire goes on the 10mm post (I think that is what size it was). You obviously know where the power wire goes. Also your about 30min drive from me. I know a few local e30 guys that wanna go for a cruise I'll pm you when that gets closer.

That sounds cool. Let me know. I'd love to join in once this thing is rolling again.

[Lof8]

are you saying I double up the small wires onto a single post?

[gregslow318i]

ok since I cant post a pic of it I just try to explain it. the lower post that uses the 10mm bolt is the main signal from the starter switch, the outer most 13mm bolt is the main 12v power port, and the upper most 8mm bolt is the underload signal to the dme, the inner most port is just used as a power port to the main starter motor. and does not have anything other connected to it other than what is already there

on any m50 based harness the starter leads are all sized accordingly if they hay not be cut or modified, I.E. 8 mm will only fit the 8mm lug tightly, 10mm only 10mm tightly and 13mm to 13mm tightly

[Lof8]

I think I'm following you, but what do I do with the extra wire from the s50 harness if I'm using the m20 starter?

[Lof8]

bump. what do I need to do to make the m20 starter work with the s50 wiring?

[bimmerboy02]

I switched solenoids cause I wanted to do everything as it was stock. The starter does work after doing this and it was real easy

[Mako18]

I just doubled mine and had no issue I am using a e34 harness on a e30 starter.

[Lof8]

I switched solenoids cause I wanted to do everything as it was stock. The starter does work after doing this and it was real easy

I like this idea

[mentaleeill]

thats weird, my m20 starter has 4 terminals. the smaller post(8mm nut) is for the unloader. it needs to be hooked up for the power windows and hvac to work.

[kevmo707]

on any m50 based harness the starter leads are all sized accordingly if they hay not be cut or modified, I.E. 8 mm will only fit the 8mm lug tightly, 10mm only 10mm tightly and 13mm to 13mm tightly[/quote]

I did this and now when i turn the key all the starter does is click once, but does not spin. My harness only has the three leads, one large, the other med, and the last small. Any thoughts

[MIKe30]

thats weird, my m20 starter has 4 terminals. the smaller post(8mm nut) is for the unloader. it needs to be hooked up for the power windows and hvac to work.

I think there is a difference between early m20 and late m20 starters. Number of terminals just may be it.

on any m50 based harness the starter leads are all sized accordingly if they hay not be cut or modified, I.E. 8 mm will only fit the 8mm lug tightly, 10mm only 10mm tightly and 13mm to 13mm tightly

I did this and now when i turn the key all the starter does is click once, but does not spin. My harness only has the three leads, one large, the other med, and the last small. Any thoughts

Make sure you have all the proper wires hooked up and not just some of them. IIRC, I have a total of 3 power wires (2 from e36 harness, one jumper to alternator) on the big post, 2 on top post 30-h (one of those is for the unloader circuit off my harness), and one on the bottom post. This is just off memory though.

Search power cables and starter wiring, FredK has a million good posts about this stuff in this forum. Just search it to verify your harness/fusebox power and your starter wiring is right. Good luck