More M3 electrical troubles...

2 weeks ago I was driving to work, windows closed I could smell a burning smell. At first I figured it was someone in front of me or something…but when I went to start my car again, it wouldn’t start. Not even try to crank over. I look under the hood and sure enough, after jump starting to car my angel eyes lead that goes to the positive terminal started smoking. Shut the car off, took the melted wire off. Cleaned it up a bit, etc.

My battery was leaking too now…so I replaced it with a brand new Mini Cooper S battery. I posted about this earlier…if you remember. Car started right away. Next day, car doesn’t start. Jump it, car runs fine. No CEL or anything. Car seems to only start when it wants to, and when it doesn’t start, it just clicks instead of trying to crank. I’ve been in and out of town and unable to work on the car much. I removed the eyes, but only took the positive lead off. The wire coming off the ECU is still connected - I don’t think that matters though. THe positive lead is off.

My only guess is I killed a relay. Any ideas? What should I look for? Fucking angel eyes, what a mistake.

Id take the car to a place to get the battery/stater/charging system check just for piece of mind if I was you don. I know you don’t live in EA anymore but we used to do it for free at the EA napa store, I’m sure we weren’t the only store to do this.

look for the starter relay…

When it doesn’t start, does everything else work?

The starter could be bad?

Dont you have CPO? why not take it to them and tell them to figure it out and give you a loaner

because he will be charged if it has anything to do with the AE’s…

check the amps of the battery to make sure it is putting enough out cranking amps, there are some issues with the CooperS/CSL batteries not putting out enough if they sit a while

I dont know why you went with a cooperS/CSL battery… i mean you nly save like 4-5 lbs over an optima and are WAY down on cranking amps

alright, I can check the battery…

if it was the starter how come I can throw a set of jumper cables on and it’ll fire right up every time?

Sounds like you still might have a draw when off. Turn off the car, disconnect the positive lead and hook up an ammeter in-line between the positive terminal and the positive cable you just disconnected. The alarm should have a really low draw. Might have to hold down the trunk sensor so that all the lights go off.

Could be a grounding issue too…

plus the mini battery seems to be ok, everyone else that has it has no troubles…the battery hasnt been sitting, its not even a week old. when we first put it in, it worked right away…

If it’s starting with a jump check your voltage across the battery terminals next time it wont start. If it’s less than 11.5 you have a draw somewhere that’s killing your battery. If it reads a solid 12 volts, then it could be a grounding issue, as brent pointed out. But i’m leaning toward a voltage draw…

I’d check for parasitic draw. Disconnect the negative battery terminal and put a meter between the battery and the cable to see how many amps are being drawn with everything off. If it’s excessive you can start unhooking things to see where your problem is.

Does nothing/clicks seems to lead me to believe it is a drain on the battery when off like previously mentioned. Especially since a jump allows the car to start.

Once running the car is fine correct? That pretty much rules out the starter. You could check the voltage while running and when off, maybe the battery is just bad?

maybe its the alternator not giving the battery a good charge when running…

ie just enough to keep it going, but not enough to allow the excess to charge the battery?

:eyebrow:

It seems to me like it is definitely related to the prior lighting situation.

I hope all is well dude, hate to see such a fine car have so many troubles.

good point. battery voltage while running should be 14-15, so check that as well.

oh it’s def the angel eyes, fucking things.

i’m going to tinker around with a multimeter when i get the chance tonight. at least check the battery and some other basic things.

So it does in-fact run fine when the car gets jumped?

If so somethings draining the battery. how bad did shit get fried when the angel eyes burnt?

nothing but the lead on the angel eyes power cable got fucked up, it seemed…not even the fuse blew heading to the eye’s relay and ECU. so it was a very easy cleanup.

the car runs perfect once it gets a jump. but i’m realizing, i always jump it from the front terminal, and i believe it didnt work from the back…

If the wire is melted it’s clearly drawing excessive amperage. I’d do the parasitic draw test 1st and unplug the angel eyes and see if it goes away. Simple test.