Sparks and smoke in cabin - Melted starter ground wire - oh boy

[Klug]

Well I'm looking like the idiot who didn't disconnect their battery before working under the hood. Doing an e36 rack upgrade, wrench slipped and hit the starter. Sparks flew and I quickly disconnected the battery. I then noticed smoke in the cabin....nothing outside the car- only inside.

Where do I start? What should I look at first before I rip the entire dash apart?

I want to cry.

[MoreMayhem]

I've seen other threads on this topic, may be able to find them with search. Good luck.

[Klug]

Tried doing some searching, but couldn't really figure out what I was specifically searching for. I'm guessing I need to see what doesn't work when I connect the battery up again....I hope it's something easy to find...

Thanks!

[bmwguy325is]

Fuseable link.

[bmwman91]

Fuseable link.

Most likely not. The fusible link resides on the smaller secondary 12V wire and it protects the fuel injection electronics exclusively. The huge black line (hehehe) supplies the starter and is unprotected.


I am assuming that the OP's battery is in the trunk? If so...
OP, start pulling carpet. The smoke is from the big black 12V wire having 100's of amps running through it and burning up its insulation and/or whatever is around it. I do NOT recommend running the car until you determine where the damage is and, at the LEAST remove the damaged insulation and wrap the area in high quality, high temperature electrical tape.

Sorry man, your rack swap job just got a lot more involved. Don't just shrug this one off though, because you are playing with a potential car fire.

[Klug]

Thanks bmwman91,

While struggling with the rack job, I ripped up the carpet in the back and found the fuseable link is in tact and not melted. And thinking about it, you are correct, I am going to have to start ripping things apart.....crap.

While the car was on jackstands, I did some visual checks under the dash and found (what looks like) where the smoke might have been coming from- the picture below is on the clutch pedal and looks odd....but granted I think I'm looking for the wiring somewhere.



I'll keep this thread updated as I dig deeper...I'm so disappointed in myself!

[bmwman91]

That's just an old clutch master cylinder. It may look burned, but it is not.

The wire that would have caused the smoke runs along the passenger side of the car. You have the battery in the trunk, correct?

[Klug]

That's just an old clutch master cylinder. It may look burned, but it is not.

The wire that would have caused the smoke runs along the passenger side of the car. You have the battery in the trunk, correct?

Gotcha, yep battery is in the trunk- The smoke was only in the cabin and nowhere in the engine bay or trunk when I ran to disconnect it- so its somewhere in there. I did a visual from the starter to the postive connection terminal on the passenger side front (where the battery would be in a vert) and didn't notice any melting or irregularities.

I'll start ripping it apart next weekend when I get a chance- Any pointers? or just go all at it.

I was going to start removing the passenger seat, pulling up the carpet and following it to the battery- if nothing there I'll have to dig into the dash and follow it :( Crossing my fingers it's not going to be that bad.

Your the man bmwman91, thanks for pointing me in the right direction!

[Vtec?lol]

If you hit the starter, check the wire that runs up to the ignition switch.

[bmwman91]

Gotcha, yep battery is in the trunk- The smoke was only in the cabin and nowhere in the engine bay or trunk when I ran to disconnect it- so its somewhere in there. I did a visual from the starter to the postive connection terminal on the passenger side front (where the battery would be in a vert) and didn't notice any melting or irregularities.

I'll start ripping it apart next weekend when I get a chance- Any pointers? or just go all at it.

I was going to start removing the passenger seat, pulling up the carpet and following it to the battery- if nothing there I'll have to dig into the dash and follow it :( Crossing my fingers it's not going to be that bad.

Your the man bmwman91, thanks for pointing me in the right direction!

Yeah, remove the seat first. That is super easy...just four 17mm bolts.

The wire that I suspect smoked up is buried in the door sill. The black plastic door sill plates are a huge pain in the ass to deal with in my experience (maybe someone here has a trick for them). I usually have to remove the rear seats and then slide the door sill backwards off of the clips (pulling it straight off breaks them). Installation is the reverse, and it sucks because the little clips like to spin. Anyway, you can pull the carpet out from under the door sill plate to gain access to the wire bundle in there but it is a pain to put it back.

Before doing that, start at the battery and work forward. If you are lucky, the damaged wire is just under the rear seat cushion.

[Klug]

So I traced the wire from the trunk to the front. Ripped apart the carpet and didn't notice anything under there. However I think I figured out where it was smoking from:





There is a light white dust on the rubber grommet, however there is nothing melted that I can tell around it. I couldn't quite figure out how to get the grommet out, I think tomorrow I'll try disconnecting the pos terminal terminal splitter thing under the the hood (where the vert battery goes) and try to slide it out to see if somehow inside of that small grommet things got melted.

Any other suggestions? or worries I should have?

[Klug]

Took the grommet out this morning, there is white chalky dust on both sides. I'm guessing this is burnt residue? Slid back the grommet and there are no signs of melting.

I guess the wire got so hot it started smoking through the grommet, since I cannot find any signs of fire/smoke anywhere but here.

Any concerns I should have before I plug this bad boy in? I dont want to rip anything more apart since I might not have any problems once its connected again.....I'm just confused where the smoke came from


Thanks

[mr ilia]

if the smoke was only minor, like more smell than smoke, then i'd just try it and see how it goes...if a no-go, oh well, at least you tried.

[Klug]

Well good thing I looked.....




This is the ground for the starter, it goes down the steering shaft to a white distro plug (which melted though but doesn't need to be replaced)

Now this is where it stops, at a ground bolt. Notice it got so hot the wire broke (in front of that orange plug)



My question is, can I run a new ground (14g wire)? Luckily it only melted the wire itself and no other wires will need to be replaced. I'm happy that I found out where the smoke came from (after ripping apart the whole passenger side)

Thanks!

[bmwman91]

Wow, good catch, and good to see that it didn't totally ruin things. See if you can find a replacement harness at a junk yard or something, and maybe splice it in.