HELP! '93 318 Alternator Problem - BMW Forum

saytuck99 · 01-31-2009, 05:20 PM

OK, so for the last year I have notice flickering etc...I figured it was the alternator/voltage regulator. Well it finally went, I was driving and everything dimmed an out I went. Luckily I was in front of the auto store. So I replace the alternator and I think all is well. Driving for 10 minutes, all the lights go dim and the car is about to stall, the n...POOF, the alternator kicks in and the car runs great for the next two hours. NOw every time I start it it does the same thing, runs down the battery until it is alsomost dead and then the alternator kicks in. The last time it happenned the car died and I needed a jump. Then it dimmied again and POOF! the alternator kicked in and car ran fine.

Once the laternator kicks in there is no flickering, all the juice is there, battery gets charged, it all is great.

SO, I thought maybe the battery is bad, but why would that matter once the car is started? Maybe I blew a fuse? Maybe something needs to warm up before the alternator kicks in? I am at a loss. This is my daily driver and I am in trouble if I cannot get to work..

PLEASE HELP!!!! Thanks...

MMSTech · 01-31-2009, 10:42 PM

Check the Alternator's ground wire. If questionable make a new on out of quality wire. I like to use 8 Gauge wire.

whonneb · 01-31-2009, 11:15 PM

It sounds like you have a bad cell on the battery which will and is killing your alternator. The alternator is design to maintain the charge in your battery, but not to charge it.

marti5 · 02-01-2009, 04:36 AM

Your alternator runs your vehicles electrical system, and left over power from the alt is then passed to the battery

Verdict: change your battery.

saytuck99 · 02-01-2009, 04:02 PM

Ground wire is fine, it loked good when I replaced the alternator. Thank you. I bought the battery and will see if this solves the problem. I will report back. Again, thank you.

saytuck99 · 02-03-2009, 03:23 PM

ok, replaced the battery. Has not dimmed or died yet, however, right around 10 minutes after I start it, battery light slowly lights up, stays on, then alternator kicks in. I am driving highway speed when this happens. I am going to start it and leave it in my driveway and see if it dies. I have no idea why it is doing this. But at least the car has not died yet, at least until this battery gets wrecked... Again, any help is appreciated..

Thanks in advance

whonneb · 02-03-2009, 07:24 PM

what was the state of the ground wires that connect from your alternator to the voltage regulator. It is vry rare that these go out, but they do fail.

saytuck99 · 02-04-2009, 07:33 AM

The voltage regulator is built into this alternator, the wires from the alternator to the car are in good shape, at least thats what my determination was when I replaced the alternator. However, on the way to work today the car died twice right as I stopped in traffic, this was well after the alternator had kicked in, started right back up no problem and on I went. Interesting though, I noticed that when the alternator kicks on after driving for a while I get some noise, like slipping belts and then it goes away. Why would I get this noise. The alternator is spinning the whole time, why when it kicks in do I get the belt noise? I am at a loss I do not know what else to replace. This is becoming a serious problem in reliability. I have had the car two years without a problem, now all of a sudden it has been unreliable...again, I could use some help...Thanks...

marti5 · 02-04-2009, 08:55 AM

I think your belt is old or your belt tensioner is knackered, not sure what you mean by the alternator "kicking in" they are working the second the engine is running??, So if you feel that its cutting in somehow it must be belt or tensioner.

saytuck99 · 02-04-2009, 10:16 AM

I did think about that, maybe when the car heats up the belt loosens up and the alternator somehow starts working. It is the weirdest thing. I say "Kick In" b/c it as though the car is running on battery for the first ten minutes or so, everything is kinda dim etc, then the battery light comes on, then the squeal starts and the power surges to normal. So in my opinion it feels and looks as thought the alternator starts powering the car at that point. I have a new alternator, new battery, I will replace the belts, I do not believe there is a tensioner as the vehicle has a dedicated alternator belt. Belts are cheap and easy I will give it a shot. Any other suggestions???? Thanks...

marti5 · 02-04-2009, 10:24 AM

Not at the moment, sounds like the belt to me as I said before there is no such thing as ALT kick in or start up, it works the minute you turn the key.