Ignition switch has no start signal, WTF mates?

[E30SRPower]

OK so as most of you know I am wiring an engine in my E30. It is a nissan engine. The starter has 2 posts, one is the thick power wire, the other is the solenoid signal wire. This wire should be live only when they key is in the start position.

According to my 1987 factory service manual (electrical, convertible), the black/yellow wire that goes to the diagnostic plug is the one. IT isn't. it is hot whenever you are in "run" position. I tested every pin on the back of the ignition switch and all of them run 12v in "run", or nothing in start. I am totally lost. Did my ignition switch go bad when I removed my old engine? how is that even possible? it worked when i drove it into the garage.

Any help is appreciated. I don't reallt want to rig the car up on switches and a button.

[rs4pro3]

black/yellow is the wire or sometimes it's just Black. Does your car have the unloader relay's in it? Did you have 2 or 3 wires orignally going to the starter?

[E30SRPower]

black/yellow is the wire or sometimes it's just Black. Does your car have the unloader relay's in it? Did you have 2 or 3 wires orignally going to the starter?

I ran a multi meter on the black and yellow wire out of the ignition switch, as well as at the diagnostic connector. Got 12v in run, as well as 12v in start. Which of course won't work.

I think I had 3 wires going to the starter... there are 2 places on the engine harness that look like they would go to the starter, both have 2 wires... plus the huge one from the battery would make 3.

And I have no idea what the unloader relay is. I can take pics if you tell me where, or you can describe it to me.

thanks for helpin out btw

[rs4pro3]

it's in the fuse box. On the 3 wired cars there is the + wire then a black/yellow and Black/green wire that go to the starter. They both come out of the c101 the black/yellow is needed to kick in the solenoid. And the Black/green wire is for the unloader relay. Do you power windows work right now?

[E30SRPower]

it's in the fuse box. On the 3 wired cars there is the + wire then a black/yellow and Black/green wire that go to the starter. They both come out of the c101 the black/yellow is needed to kick in the solenoid. And the Black/green wire is for the unloader relay. Do you power windows work right now?

I ALMOST MENTIONED THAT!

I cannot believe you asked it either. They sure don't. From what I have heard thewre is a wire that I need to ground to make them work. I have not grounded my engine block yet... but there is nothing BMW hooked up to it at all.

[rs4pro3]

Ya that black/green wire has to be grounded. Your windows arn't workind due to the unloader relay, when you crank the car the starter breaks the ground going to the relay stopping some of the accesories from working so the battery has more juice to crank with.

[E30SRPower]

I don't have a black and green wire. There is a solid green and a green and yellow wire though.

[rs4pro3]

Pin 15 in the c101 is for the Black/Green wire(on the car that has it) Pin 18 should be for the Black/Yellow wire going to the starter.

[E30SRPower]

Pin 15 in the c101 is for the Black/Green wire(on the car that has it) Pin 18 should be for the Black/Yellow wire going to the starter.

I don;t know if the connector is called c101. It is the one that connects the engine harness to the fuse box. My pin 15 is WT/YL, motronic control unit (RXD), and pin 18 is GR/BU, Motronic control unit (Programming Voltage).

pin 11 is the black and yellow wire, labeled "starter, Start signal (50)"

[rs4pro3]

That's the connector.(round on the side of the fuse box) I think your wiring diagrams are WAY off. On every single E30 with the c101 Pin 18 is the Black/Yellow wire for the starter. Even on a E32 735i. Are you sure you are reading the pin numbers on your plug correctly? Yellow/White should be in pin 8 and it's the Fuel rate output

[E30SRPower]

I think your wiring diagrams are WAY off.

I am getting my info from the BMW factory service manual (electronics one). It is the same book the technicians at the dealership use while working on our cars.

[rs4pro3]

That is the Diagnostic Connector not the c101, Nothing plugs into it. It's purely for diagnostic purposes to read codes, reset the oil service light etc.. THe c101 is the large round plug right on the side of the Fuse box.

[E30SRPower]

Oh. I found the C101 in the FSM, but it doesn't have a pinout. I would think they would. where are you guys getting your info?

[rs4pro3]

ETM, manuals put out by BMW, there are CD sets on eBay, I'll send you some pin outs I've gathered tonight threw email.

[E30SRPower]

great. thank you so much. It's srjoeydet(at)yahoo.com if you don't have it yet.