Help wiring m30b35

bavarian

bavarian

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Hey so I’m close to starting the b35 that I have swapped into my e12 and I have a few questions.

The e12 has an alternator and starter engine bay harness , the e34 harness has starter wires , I was going to use the stock e12 engine bay harness and wraps the e34 starter wires , here we had double starter wires I’m thinking go e12.


The e34 has a clearly marked red set of wires where the positive is supposed to go to maybe to power the ecu, can I wire the e12 coil pack positive to the ecu power which should give power to the coil pack , I already forgot how it goes

Basically I have fuel pressure at the rail , I can get the starter to spin I have all sensors and everything plugged up, but I’m looking for what wire is needed to power the ecu , I just want to hear the motor run then I also would like to find the rpm signal to connect the b35 revs to the cluster , would the green distributor wire from the e12 get me that and would I connect that to the coil pack to get the rev?
 
The 179 computer is turned on at pin 27. That comes from the green wire at the coil which goes straight to ignition switch.

The main power to ecu is at pin 18. It gets connected to the 8mm stud on starter that goes to battery.

Do not connect red wires to green wires, coils to main battery power, green wire at coil to tach.

you will likely regret it.
 

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According to DIN, used in 80'a, 90's... wire colors matters.

Basically:
- red (battery/alternator circuit) plus color to mark specific sub-circuit
- green (switchable incl. coil battery - after ignition switch plus optional colors to mark specific sub-terminal
- brown (negative battery - aka GND), also used for GND-operated lines like for example some sensors, indicators etc.
- other colors are also typically use specific but the three above are the most important

That's why Don warned you not to connect green with red as it will connect switchable battery with non-switchable which in result will drain your battery and/or make the car inoperable.
 
Here is a chart from BMW for the wire colors. It is for the e3 but E9 is the same. Unfortunatley is is in German, for myself it does not matter.
 

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Sorry I’m a noob with wiring and the lingo confuses me, I’m guessing you guys are describing the connection from the fuse box to the m30 b35 but I’m still at at point where I just want to start the motor in the car but I will need this valuable info you guys provided when I dive in further! So thank you! Here I have some diagrams that I believe were posted by other forum members and at this point I’m trying to do the least possible just want to hear the motor run. What I have done is put power to #10 on the diagram , I have wired my original e12 starter and alternator wiring as the starter and alt have the same conections , however don I did not wire the starter conections on the b35 harness just on the e12 , I can get the motor to spin now but does the ecu get power from the starter wires and not #10 on the diagram ? Also I have wired the coil pack with just the b35 harness no positive straight from the battery , and no e12 wires since I thought when I put power to #10 on the diagram it would power the whole thing
 

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things I’m unsure of still
I hooked up the original e12 starter wiring this new starter has two hole or loop conections would I also connect those with the e12 starter wiring , I’m seeing double starter conections one from e12 one from b35 harness I figured the e12 would be enough but if the ecu sees power from there I would need to hook it up right

Another double wiring I’m seeing is the coil pack there’s b35 coil pack which I’m using along with the b35 wiring , all checks out but now the e12 also has coil pack wiring available and I’m unsure if the positive at #10 on diagram would provide the coil pack power or if need to hot wire the coil for now
 
I don’t understand what a pinouts are .I thought they were the ecu pins and I’m unsure how or why I would be touching those
 
bavarian said:
Sorry I’m a noob with wiring and the lingo confuses me, I’m guessing you guys are describing the connection from the fuse box to the m30 b35 but I’m still at at point where I just want to start the motor in the car but I will need this valuable info you guys provided when I dive in further! So thank you! Here I have some diagrams that I believe were posted by other forum members and at this point I’m trying to do the least possible just want to hear the motor run. What I have done is put power to #10 on the diagram , I have wired my original e12 starter and alternator wiring as the starter and alt have the same conections , however don I did not wire the starter conections on the b35 harness just on the e12 , I can get the motor to spin now but does the ecu get power from the starter wires and not #10 on the diagram ? Also I have wired the coil pack with just the b35 harness no positive straight from the battery , and no e12 wires since I thought when I put power to #10 on the diagram it would power the whole thing
Click to expand...
Before you call Don check what kind of ECU number (BOSCH) you have and what was the donor car production date. Maybe even VIN of donor car might be needed to make technical check more precise.

Some DME/ECU needs specific signal to Enable starting (coming from DWA - Alarm System). In most of cars this circuit is shorted in the body car harness, so you might be needing to bridge that.

I hope Don will be able to help you as direct contact is far more efficient than even regular but message exchange.

Good luck!
 
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