E30: Ignition Coil Order

[jolle21]

Afternoon folks - was hoping you can help this noob...

Background; picked up a 1991 318is M42 from a donor that was in an accident. Few parts were missing, including the coil packs. Guess the owner was parting out the car before I got to it.

Anyways, I'm either going with COPs or the OEM setup, but I'm having trouble identifying what the number is for each of the connectors on the wiring harness. Basically I don't know what connector is for ignition coil #1, #2, etc.

Anyway this can be determined? Thanks!

[DesktopDave]

It's in the ETM. IIRC the trigger wire is in the center of each coil plug, if in doubt it's a black wire on the E30. Each coil will also have a green wire as common power and a brown/orange as common ground.

Pull the connector off the Motronic, find out where these pins go to:

Coil #1 is DME connector pin 25.
Coil #2 is DME connector pin 52.
Coil #3 is DME connector pin 24.
Coil #4 is DME connector pin 51.

[wazzu70]

For whatever reason BMW didnt find it necessary to identify which lead went to which coil. Your best bet is as mentioned....tracing back to the ecu.

[ryanjv]

For whatever reason BMW didnt find it necessary to identify which lead went to which coil. Your best bet is as mentioned....tracing back to the ecu.

Mine is labelled pretty well.  The black cover that goes overtop of the 4 ignition coils is labelled 1 through 4.  Then the wire leads had numbers printed on them as well to tell you which coil they connected to.  Since they were different lengths it's easy to tuck them into the wire tracks to put them into their proper hole.  it's pretty straightforward if you follow the pathways and do the proper wrap arounds (like how 4 goes all the way around 3)

here's a picture to show how it wraps around to help with routing
http://www.m42club.com/forum/index.php?topic=10286.0

[wazzu70]

Very true! Unfortunately if you remove the leads to the coils from the ECU....there is no identification on those. Don't get them mixed up or label them before you remove them!!

[colin86325]

I labeled my ignition leads using zip ties that I trimmed after installing.  I put one zip tie on lead #1, two zip ties on lead #2, and so on.

I really like my ghetto solution!

[DesktopDave]

I labeled my ignition leads using zip ties that I trimmed after installing.  I put one zip tie on lead #1, two zip ties on lead #2, and so on.

I really like my ghetto solution!

That's not ghetto at all - very clever, and very permanent.

Zip ties are my new duct tape, LOL. I got a laugh out of my mechanic when I used zip-ties to repair blown out end links on the wife's minivan!

[jolle21]

thanks for all your help guys...i'm guessing all this means that i'll have to cut into the wiring harness insulation/jacket?

[bmwman91]

Wiring diagrams here:
http://www.m42club.com/forum/index.php?topic=5098.0

You can just use a multimeter to check for continuity between the coil plugs and the terminals on the ECU, no cutting required. Just take the big connector off of the ECU and you should be able to touch the DMM probes to the terminals.

[DesktopDave]

+1 - no need to pull any insulation. Pull the DME connector off - look very carefully - you should see tiny little numbers printed there for the correct pins. Run your DMM leads out to each coil connector and you'll know which connector goes where.

You can also split the DME connector open to get at the crimped end of the harness - it usually has a single screw & sometimes a zip-tie holding it together. Once you've removed those, the cover slides off.

[jolle21]

THANK YOU GUYS!!!