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Ignition Coil Wiring


Jason Dittmer
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Jason:

 

Your coil looks like an aftermarket with an internal resistor.  In that case, you shouldn't run the original resistor wire that is in your blue sheath, you should trace that wire back to fuse #12 on your fuse box and replace it with a straight wire connected to the "+" side of the coil.  Then connect the red "+" and black "-" wires coming from the "Pertronix?" unit inside your distributor to the coil.  The only other coil connection is your tach wire that runs from the back of the tach to the "-" side of the coil.  All the other wires in question look like they connect to the smog components.  Crank the motor and ground a plug wire to see if you have spark.

 

I thought I remembered that the E30 M10 motor used a different cam gear that spun the distributor counterclockwise.  Spin the motor clockwise with the distributor cap off to check the direction of the rotor, if this spins counterclockwise, you may need to change your plug wire arrangement to get the proper firing order.

 

Good luck,

 

 

Mark92131

 

 

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2 hours ago, Mark92131 said:

Jason:

 

Your coil looks like an aftermarket with an internal resistor.  In that case, you shouldn't run the original resistor wire that is in your blue sheath, you should trace that wire back to fuse #12 on your fuse box and replace it with a straight wire connected to the "+" side of the coil.  Then connect the red "+" and black "-" wires coming from the "Pertronix?" unit inside your distributor to the coil.  The only other coil connection is your tach wire that runs from the back of the tach to the "-" side of the coil.  All the other wires in question look like they connect to the smog components.  Crank the motor and ground a plug wire to see if you have spark.

 

I thought I remembered that the E30 M10 motor used a different cam gear that spun the distributor counterclockwise.  Spin the motor clockwise with the distributor cap off to check the direction of the rotor, if this spins counterclockwise, you may need to change your plug wire arrangement to get the proper firing order.

 

Good luck,

 

 

Mark92131

 

 

 

 

Wow good comment on the distributor spinning backwards. OP definitely crank the car over with the distributor cap off and see which way the distributor rotor is spinning and then wire the spark plug wiring order accordingly!

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I think there is more than that.  What is in the link is a simple ignitor and it may be enough but you should examine a wiring diagram for a 318i to see what all you need.  The ignitor has no advance function and unless the distr has it something else has to provide.

There has to be others on here who back fit a 318 engine that is more familiar with it.

 

Edit:  I just got smarter on the topic after pulling out a Haynes manual for the E30 and yes the ignitor is all you need.  There should be a two wire connector from the distr to the ignitor   You should get the connector to the ignitor also.  From my collection of notes, Ignitor pin 1 - coil netative, 2- chasis ground, 3 - shield ground or not used, 4 - switched 12V or post on coil with the 12V switched power, 5 Not used, 6- signal from distr, 7- Tach out (but it will be square wave and tach may not work, if so need a tach adapter).

Edited by jimk
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Sorry for speaking shop talk instead of BMW talk.  That link to partsgeek part is commonly called an ignitor, just like the Pertronix replacement for ignition points is called an ignitor only the pert in the link is mounted remote from the distr.  Not all ignitors are alike, some are triggered from a hall effect pickup (and from ECUs square wave signal) and others are triggered by a reluctor pickup.  This one is a reluctor triggered type.

The 2002 distr is designed to turn clockwise, not only the gear but internal parts as well.  It would be a big deal to change the camshaft so the 2002 distr could be dropped in.

It sounds like you don't have the original distr wiring harness either.

Edited by jimk
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Where is the reluctor triggered type pickup? How do I hook it up?

 

I have the original wire-harness from the 318i. And I found the distributor control unit. I don't have schematic for the 318i. I'm not sure what wires go where. Some of the wires connected to the distributor control unit go to the fuel injectors. Obviously I don't need that right? Hopefully not because I'm wanting to keep it carbureted. 

Edited by Jason Dittmer
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The reluctor trigger (pulse generator) is within the distr. It is below the rotor and the smooth big round dust cover.  It does not need and messing with if it ran ok before which I expect to be the case.

You can open up the harness where the injector wires come off of and remove them because they are not used here. Do that last so you don't cut any needed wires.  There should be a small two wire connector that plugs into the side of the distr.  You need to mount the control unit (ignitor) with the heat sink somewhere under hood. I presume you have a Bosch ignitor, if so disconnect the big connector.  Near the spring clamp will be terminal numbers on the connector.  Terminal 4 will be +12V and the wire from it is to be connected to the coil post that you have +12V switched. Terminal 2 is ground and is to be connected to a chasis ground point.  Terminal 1 is coil is to be connected to coil minus (-) post.  Find the correct wires for these terminals with you continuity tester. Terminal 7 is tach out but I doubt that the tach will work as the signal wave form is for the new digital tachs.  If so you need a tach adapter. 

This system is a capacitive discharge design and no resistor is needed in the 12V feed to the coil.

Suggest you record the wire colors and make a simple wire diagram for future use.

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