So today I started having a strange issue with my R53. I took a trip today, and the first thing I noticed was when I stopped for a coke and turned the car off. There was a loud POP! in the stereo that has never happened before. When I restart the car, the radio has reset; it's off, on "Tuner" instead of "Bluetooth" (it's aftermarket), and the clock is reset. Later I notice that the clock on the roof has reset too, so when I shut it off the power went off for the entire instrument cluster at least.

I get to my destination, it does it again; a loud pop, but this time while I'm still driving, while I'm backing in a parking spot. I also notice that my power steering goes out for a couple of seconds then comes back. On my way home later, I stop at a store, and it does it again while the wheel is turned to the far left as I swing around for a parking spot. Then, when I get home, it does it one last time as I turn the wheel hard to the left to go up in my driveway. I pull in my carport, turn the car off, and discover I have no electrical power at all; no lights come on, I can't get the boot open, nothing happens later when I turn on the key. It's kaput. Later on, I go back out after about 1/2 hour, and suddenly I have power again.

To summarize, the symptoms are:

• Seems to shut power down when I turn the car off, at least this last time; maybe each time, as I was leaving the car for a bit each time it happened today.
• When I turn the car sharply, at least to the left (didn't notice it when I turned right, but I wasn't making many sharp right hand turns that I can recall), I'm getting a loud pop like I do when I'm shutting it off.
• The power steering goes out when I turn and get a pop, leading me to believe that the electrical system is shorting out entirely when this happens. But if something was shorting out, I'd expect fuses to be blown and things not work at all until I replaced them.

I guess I'm lucky this is happening now instead of a week from now when I'm at the Dragon, but if I don't figure this out I can't go. Any electrical gurus have any idea what it might be, or at least what I need to be looking at?

 

I had similar problems when my battery was going bad. I would start at the root of all power to the car. The battery, make sure it has and holds a charge. Then check the alternator then check all the ground wires for your aftermarket electrical components.

 

Yup...
Check the battery and the alternator....

 

Well, I think... THINK.... I found the culprit. It was still driving me nuts that I couldn't consistently replicate the problem, so I decided to start with to pull the power to my sub amp, since that's the only thing I've messed with lately that had anything to do with power. After I pulled the power wire to it off of the battery terminal, I started to put the nut back on the connection when the whole car went dark again. I pulled out my multimeter to start hunting the problem; if I could figure out where I wasn't getting power, maybe I could figure out what was causing it. Starting at the top, I checked the big battery terminal beside my air filter, and that's when I got my first "WTF" moment. I had 1.24 volts to it, and I should have had over 12v. That didn't make sense, since it is wired directly to the battery terminal. I could see having zero volts more than 1.24, that really didn't make sense. Then I checked my ground from the top, and got my next "WTF". When I touched my socket wrench to the bolt on the body that the battery ground attaches to, I got a small shower of sparks. That should never happen. That's when I noticed that the manual trunk release cable (it was from the burned donor car my motor came from; I haven't hooked it up yet as it's got a lot of fire damage) was running beside the ground, and had fallen down beside the battery in the battery compartment. As I started to pull on it, I was seeing sparks from several places along it. Screw that, I didn't like the fact that it had exposed cable showing through burned spots anyway, so I just cut it and pulled it out. Looks like it was grounding out something somewhere, and that was enough to make the electrical system all wonky. I just drove it around for a while, cycled the power steering to the limits a lot, turned it off and on, and haven't had any problems. Hopefully it's fixed now, and I'll be good for the Dragon. Thanks for all the advice, everyone.