Problems charging?

[Shanes325]

Okay when I got this car it had it's share of problems. Well one of the things that's still wrong is. the car will go dead if u leave the battery hooked up for more than a couple hours. And the car will not charge till u rev it one time to 3k and then it charges fine until u turn it off and unhook the battery. Ohh and I have receipt where the alt was replaced about 3 months ago.and I just replaced the belts . Any tips would be a great help . Thanks in advance.

[Jaxx_]

is your cluster bulb out? and is your car an 87 or earlier?

The issue is the exciter circuit going to the D+ terminal on the alternator. it's blue and like a 18ga wire. it goes to the blue harness at the cluster.

[Shanes325]

Car is a 86 325e and the cluster light works . So r u saying it's lose or what will go check asap.

[Shanes325]

Hey guys I could really use the help.can anyone direct me in the right direction?

[nebulous123]

my guess is the voltage regulator maybe? if they alternator was replaced i imagine thats new. but i guess it could always go bad. its a $20 part.

also does the battery die even if you fully charged it with an actual battery charger?

if you are talking about recharging from the car running then alternator is definitely where you need to be looking.

my battery kept dying and I couldn't figure out why. turned out the nipple that turns the trunk light on and off wasn't pressing flush with the trunk plastic seal so the light was on all hours of the day. since i figured that out no problems.

have you tested the voltage with car off and car running?

start there then report back

[Shanes325]

Yea the alt is new okay so when u first start the car it charges at 4volt and if u rev it one time real quick to 3k and it idles back down it charges at about 13.5 volts. And yes if the battery is fully charged from a charger if u go back to start it in a little bit it's dead or near dead. I checked the trunk light also and it turns off just fine.... Wth? Is wrong with the pos and iv checked wiring for nicks or tampering.... Nothing all good. I'm At a lose I really don't knw where to go from here.

[nebulous123]

well with the car off you should have 12 volts at the battery. with the car on and before you rev it whats the reading at the battery? still 12 or 13.5? and after the rev whats the reading at the battery? report back

[scrowner]

Could simply be a bad battery. You can check for a bad switch in the car - leaving a light on - by checking the current draw at the battery. I think with the car off you should see less than 0.050A. But your description leads me to believe your battery is not holding a charge.

[kid325e]

Scrowner may be on to something. I'd reccomend getting a new batter if it's older than 2-3 years old. If you think it may be good, it might be worth having a shop test it with a "Good" battery tester. Hope you get this figured out, coming out to a car with a dead battery is no fun!

[603Racing]

Did you get this resolved? I have the same issue, battery light on at low RPM's, but if I rev it past 3k one time then it seems to be fine for a while. I'm getting the Park Brake and Brake Fluid lights fading in and out in sync with the battery light.

Only issue I know of is the reverse light wire is split. I know that can be an issue, but I don't see how reving it past 3k would fix it temporarily.

My car is a '90 325i. I think I might try the voltage regulator after I disconnect the reverse light wire.

[603Racing]

If your problem turns out to be the regulator, here's a helpful write-up.

http://www.r3vlimited.com/board/showthread.php?t=193018&highlight=voltage+regulator

[603Racing]

Did you find the cause of your problem? I am curious. I am going to replace my alternator this weekend. I was just going to replace the voltage regulator but I found a good, used Bosch alternator for $20.