Ignition Coil Wires - Continuity with Ground with Fuse #10 Inserted (M42)

[jrobie79]

So I've been trying to diagnose my no start issue on my m42 (e36 m42 installed into e30). I initially thought it was the CPS, swapped that out, no dice.

While diagnosing and checking continuity between the different components (DME, Coils, Switch, Fuel Pump, CPS's, etc...) I noticed that the Green wire to ground for all 4 ignition coils only read 7Ω.

I started tracing wires to discover if there was any spots where the wire insulation was worn and/or cut that would indicate near continuity between ground and the green ignition coil wire.

What I figured out was that this wire leads back to pin 7 in the C101. so I unplugged that. The body side of C101 read open from green wire to ground, so that was eliminated. Then I disconnected the ignition switch plug and read that, open, eliminated that section.

What I discovered was that if Fuse #10 was plugged in I was getting the 7Ω reading, if I took fuse #10 out, the Ω jumped to 300+.

Kind of stuck where to go from here, I dug through all the wiring diagrams, but I'm still have trouble where to go from here.

Any advice?

I put all the pictures of wiring diagrams from the ETM that include fuse #10 below:

[wilholl]

FWIW...
my fuse #10 problems have always been related to the reverse switch harness under transmission tunnel.
In one case, the wires dropped out of the holding clips and got chewed up and shorted out by the drive line (Guibo)
in another case, lifting the motor and trans to replace mounts, the reverse switch terminals got smashed together and shorted.

You might try checking these out

[jrobie79]

FWIW...
my fuse #10 problems have always been related to the reverse switch harness under transmission tunnel.
In one case, the wires dropped out off the clips that hold them and got chewed up and shorted out buy the drive line (Guibo)
Other case, in lifting the motor and trans to replace mounts, the reverse switch terminals got smashed together and shorted.

You might try checking these out

yeah I remember I had issues with that before, and sure enough that wire was shredded. I'm going to check that first as soon as I get home from work. Just odd. I'm not an electrical guy by any means, but I think 7 ohms is close enough to a short that it could be the reason my car wont start, the coils might be getting all fucked up because of it.