Intermittent Electrical Surge/Power Cut-Off

[nmulax]

So took the Z4M out of storage a week or two ago; and have have driven it maybe 5 days in that time period. At least once, each time I've had it out, I'll get an intermittent loss of power to some of the electrical components.

Symptoms:

1. Hardwired V1 will reset.
   This has been hardwired into the map lights for almost 4 years. My first thought was a loose wire, but given the other issues I think it could be something else. It doesn't stay off, it always just restarts as if it was unplugged and replugged immediately.
   
2. AUX input goes dead (typicall for a second or two, up to a minute).
   When it died for a prolonged period (over a few seconds), I switched to Radio, which played fine… seems like it's only in AUX mode that it cuts out… then again, I never really listen to the radio or cd, so it may happen regardless of the audio mode.
   
3. Some of the dashboard lights will flash.
   I've only noticed this once (today). A few of the lights flashed yellow for a moment. I believe it was the ABS, BRAKE, and DSC… but don't quote me on that. I was sitting at a red light and glanced down just as they turned off.

When this happens, I don't notice any drop in performance/engine speed. The speedometer/tach never drop (as with an alternator issue). The nav screen stays lit, and the clock hasn't reset. It's happened while stopped, around town (30-40 mph), and on the freeway (70+ mph).


Any ideas?

[BruceJ]

Electronic tech Mantra - (that we forget about until it beats us for about 10 years) check the easiest cheapest first

Visually and physically Check V1 connections - pull them, clean them and reseat - wouldnt ignore this - especially if it was the last thing you touched electrically.
Direct battery connections - pullem, cleanem, reseat
Have battery tested - the squirrly ABS, DSC lights may be indicative of low voltage.
Body Grounds - Shipkiller had a thread or comment/electrical issues, think he mentioned where they are located - same thing, pull clean, reseat.

Good luck

[nmulax]

Thanks for the suggestions! Going to follow your steps and see what I find.
Also may remove the V1 for a few days to see if that eliminates the issues.

[ZStig]

Originally Posted by nmulax

Thanks for the suggestions! Going to follow your steps and see what I find.
Also may remove the V1 for a few days to see if that eliminates the issues.

I have been battling the same electrical gremlin for months. Beedub had the same problem. In both of our cases a fresh battery was the resolution. For me, it seemed to happen more often in the rain so i always thought it was an electrical short

[Jmanscotch]

I had these same syptoms on my E46, turned out to be a loose negative connection at the battery. If you had your car on a battery tender during storage, I'd start by simply ensuring good tight connections. If you didn't keep the battery charged, I'd go with Roffle and start by replacing the battery. Many, MANY, unexplainable electrical gremlins on these cars are caused by weak batteries.

[gferil]

I had the dashboard light problem, and it turned out to be a low battery. Replaced the battery and have been fine since. I also experienced the windows sometimes not doing the "one touch close", and my SA told me that is due to a low voltage in the battery, which causes the windows to re-initialize themselves.

How long have you had the current battery for? Did you hook it up to a tender during storage?

[gizmo83]

I've had similar problems and it was my battery dying, replace it and all was fine. These things need full power or crazy things start happening.

[ZStig]

Wish everyone was this knowledgeble when i posted my thread a while ago, would have saved me a lot of hassle. Lol. Except not really lol

[WestCDA]

Did you have the battery disconnected in storage? Sure sounds like a low/intermittent voltage issue. Check/clean/resecure the battery connections and make sure the battery is fully charged (and capable of retaining it).

[nmulax]

I've determined the audio mode (aux/radio/cd) has nothing to do with the power cutout… it happens in each mode. Also, the dash lights flashing has (thankfully) only happened once.

The battery was not disconnected nor on a tender during the winter. I'd just start up the car once a week and let it run for 20-30 minutes. I'll check this evening, but I believe the battery is 2-3 years old; so that could very well be the culprit. Regardless, I'll go through and check all the connections and test the battery. Hopefully it's as easy as replacing the battery.

Thanks for all the feedback/comments!

[WestCDA]

20 minutes might not be enough to recharge the battery for the energy it took to crank the starter, especially with the low alternator output at idle - so you could have slowly been depleting the battery charge over the winter.

Starting it briefly in the winter usually does more harm than good - it puts moisture into the oil, and the engine never gets hot enough to boil it off like it would on an extended drive. You'd be better off using a battery tender for those few months it is in storage, to keep the battery at it's peak - if that's an option for you.

[nmulax]

Just an update:

Checked all the connections/grounds on Thursday and couldn't find anything out of place.

This morning I went to O'Reilly's and had them test the battery; 11 volts, and 14% charge. Bought the AGM SuperStart battery for $160. As I was leaving, the car started to struggle while waiting for the light to turn green, so I went straight to my dealer. $58 and 30 minutes later, the new battery was installed.

So far so good. Only time will tell, but hopefully the weak battery was the cause of my electrical issues.
Thanks for all the feedback and insight guys!