new alternator and new battery and it still dies?

[DownTown Import]

Ok did 5-speed swap, car was running fine before.

Now my car died, guages went out and lights died, so replaced battery and alternator. Ran fine for few hours then did the same thing agian. The only thing i did durring the swap battery wise was remove starter.

What would be making this happen? Connection on starter?

Has anyone had this happen?

I am about ready to part this thing out or sell it i have been having so many issues.

[DownTown Import]

Bump

[thejlevie]

What was the battery voltage after the car died? If below 12.4v the battery is being run down (charging problem or excessive current draw).

[DownTown Import]

I don't know. But everything died on it slowly. Now the alt I put on it was out of 97 328i. Used...

I was thinking maybe this one also didn't work. This is driving me crazy. But it wouldn't have anything to do with starter wires right? I mean the starter works so that isn't the issue.

Any place but a BMW dealer that has alternator?

[DownTown Import]

I did tranny swap as well. From auto to manual. Does that have anything to do with it?

[trayson]

I don't know. But everything died on it slowly. Now the alt I put on it was out of 97 328i. Used...

I was thinking maybe this one also didn't work. This is driving me crazy. But it wouldn't have anything to do with starter wires right? I mean the starter works so that isn't the issue.

Any place but a BMW dealer that has alternator?

Do you have a voltmeter? With the car running and most things turned off, you'd expect it to be I think 13 or 14 volts. Then test the battery with the car off. You'd want it to be over 12 volts.

I have an alternator that I took out of my 328i. It will work in the M3 just fine. It's an 80 Amp Valeo, and it has the Valeo pulley so it would be a direct swap for either a Bosch or a Valeo. I have it for $65 on Craigslist. I know for a fact that it works just fine because I took it out of the car myself. (I wanted a 140 Amp Bosch because I run a bunch of stereo stuff, but the 80 Amps will have a smidge less draw on the HP of the motor--Not that you would ever be able to notice it)

[trayson]

I did tranny swap as well. From auto to manual. Does that have anything to do with it?

The only thing I can think of where one would affect the other is the length of time that it took to do the job. Often, if a battery's failing but you are driving it every day, then the alternator keeps it charged up just enough to start the car. You don't end up seeing the fact that it isn't holding a charge for long.

But if you had the car sitting for a few days to a week while doing the swap, it could give your battery a chance to run down. Now, it's possible that just the battery was bad, but it's also possible that the alternator was bad, leading to running down the battery and killing both.

See my post to test them.

Lastly, there is a small possability that you have something that's hooked up incorrectly or something so that it's drawing power when you're car's off. That's a bit more of a hassle to check. You put your multimeter on "Amps" and measure how much current is being drawn with everything in your car off. The multimeter goes in between the battery's negative and a ground. With everything turned off, it should be in the SMALL milliamps (to power the clock or car alarm). If you have a larger current draw, you've got a "leaK" that's killing your battery while your car's off. to find the "leak" you start pulling fuses until the larger amp draw goes down to a tiny number. Whatever fuse you pulled that causes it to drop significantly is your culprit for what system is causing the rundown of your system. but again, this is not a likely scenario. I would check the battery/alternator first.

And congrats on the Manual swap. Slushboxes are lame.

[DownTown Import]

Its a BRAND NEW battery that and it went dead in an hour of driving. I don't think its the battery. And i don't think 2 alternators would be bad. I touched no wires when doing tranny swap but the starter and I put those back.

[HassounM3]

Trayson's post seems spot on... Have you checked the volts at the battery with the car running?? Should be 13-14V range, if it's lower, your alternator is bad... Check the Volts at the battery then go from there...

[trayson]

Its a BRAND NEW battery that and it went dead in an hour of driving. I don't think its the battery. And i don't think 2 alternators would be bad. I touched no wires when doing tranny swap but the starter and I put those back.

And you're basing this on what kind of testing?

Unless you have some magical powers to comminicate with the alternator, just do what I said and test it with a multimeter. I've written out exactly what you need to do to diagnose your problems, now get on it.

Facts are always more helpful than assumptions.

[DownTown Import]

just tested with friend, alt is putting out 22 volts. It seems like the red wired going to battery has no connection.

It's like the car was on but like the car just wasn't getting the power from the alt.

What would that be? where should I trace alt wire to? Because it won't stay running long for more then five min without being hooked to the other car.

[DownTown Import]

what could be drawing power? I mean the starter wires only went on one way really. I didn't mess with anything else durring tranny swap other then the jumper line from the starter black/yellow under dash to the plug in the auto tranny harness.

[DownTown Import]

SOOOO....

:)

To help narrow down the thread. The car is running off battery power only really, Alt IS good, but it just isn't getting power to the car. We tested and it gave us 22Volts. From posi on the back of the alt, to the ground in engine bay.

Relay? I have no clue where the wires from alt to battery go.

[bmwf106]

22volts? thats not right. recheck it. or while the car is running, unhook the battery. if the car dies then the alternator is bad. dont argue, just do it and shut up.

[DownTown Import]

Ok I tested BOTH at NAPA and BOTH are good...

The alternator is fine. BUT when I unhook battery it does die.

So...any thoughts?

[bmwf106]

Ok I tested BOTH at NAPA and BOTH are good...

The alternator is fine. BUT when I unhook battery it does die.

So...any thoughts?

are all of the connections secure on the alternator? keep in mind if the car is running the battery does nothing at all. I change out batteries with cars running all the time. is the battery light illuminated on the dash when the car is running? how long does the car run with the battery hooked up? how long does it take to die if the battery is unhooked?

[DownTown Import]

Battery is keepin car running when I unhook the neg side on battery it dies right away. Alternators are perfect. Connections are good.

Is there any fuse or anything else to check?

[trayson]

I agree 22 volts doesn't sound right at all. The alternator should be at around 14.x volts tops. Under 15 for sure.

Part of the alternator setup is a "voltage regulator". I don't know a ton about how they're supposed to work, but my educated guess is that they are what keep the alternator generating at under 15 volts. So, maybe since you're experiencing 22 volts, the voltage regulator is not functioning?

I can only speculate that too much voltage would be just as bad as too little. Try looking into that direction.

They look like this:

http://www.autohausaz.com/secure/PartImages/1197311225.jpg or http://www.autohausaz.com/secure/PartImages/12321739435.jpg or http://www.autohausaz.com/secure/PartImages/1197311028.jpg

[bmwf106]

I doubt it is running 22 volts. and you are right it should be below 15volts at all times.


SO guy, answer my questions................. is the light on the dash exc.... I get the car dies as soon as the battery is unhooked. its no doubt a charging issue. Are you sure all the connections are secured? Dont think fuses.... let me go look around my car and maybe i will think of something..back in a min

[DownTown Import]

Thanks man your awesome! I am not sure from posi on alt to neg on chassis ground said 22 but I could be wrong. Any help would be great.

[DownTown Import]

Hmm if that voltage regulator went bad what would that do?

[DownTown Import]

Hmm if that voltage regulator went bad what would that do? Could that blow a fuse or anything.

[Jrdeamicis]

Sounds like something is drawing power that shouldn't.

[egebhardt]

The alternator should put out 14 volts. Replacing the voltage regulator is less than $100 bucks. The (larger) 140amp alternator takes and extra 5hp to run, per a Dyno I read here somewhere, plus it weighs 5lbs more and costs more.

[DownTown Import]

Say for instance it was unplugged ( the volt reg). What would happen?

[trayson]

The alternator should put out 14 volts. Replacing the voltage regulator is less than $100 bucks. The (larger) 140amp alternator takes and extra 5hp to run, per a Dyno I read here somewhere, plus it weighs 5lbs more and costs more.

5 hp? Really? hmmm... doesn't seem like it would affect things THAT much, but I guess if they did a dyno, then those are hard facts to dispute.

Now, would that be 5hp at the MAXIMUM draw of each relative to the other? Because in theory, if they were both had an identical 60 amp load on them, wouldn't they put out the same amount of resistance (load) on the motor??? (I admidt that I don't completely understand the physics, so that's why I'm asking)

[Jrdeamicis]

Say for instance it was unplugged ( the volt reg). What would happen?

An empty wallet? There is other ways to diagnose this issue.

[DownTown Import]

Bump

[trayson]

Say for instance it was unplugged ( the volt reg). What would happen?

I don't know for sure. My gut tells me that if the voltage regulator was not working in some fashion, that it wouldn't regulate the voltage of the alternator, and you'd see higher than 14.x volts. That seems to be what you're experiencing, (assuming that you did measure the voltage correctly @ 22) so that's why I suggested you look there.

Beyond that, I don't know what to tell you. We've given you lots of areas to check out and to look into. But I'm not an "alternator expert", I've just had to deal with a few electrical gremlins in my day. So, hopefully we've given you enough input that you can take it and run with it. Or at least you can have specific things looked at and/or verified by a shop.

Good Luck.

Honestly, I don't know how to specifically test a voltage regulator, but there's undoubtedly a shop around you that does.

[David357]

Probably a short

[theMIJ]

going on the assumption that you measured correctly and your alternator is actually putting out 22 volts:
1. your voltage regulator is jacked up. go get another one. unplugging it will keep the alternator from working at all.
2. 22 volts can cause electronic control units (engine control unit especially) to operate erratically and may even damage them permanently.
3. disconnecting a battery cable with the engine running is a really bad idea, it can cause a voltage spike in your electrical system, which could also permanently damage control units.

[bmwf106]

[
3. disconnecting a battery cable with the engine running is a really bad idea, it can cause a voltage spike in your electrical system, which could also permanently damage control units.[/quote]

Repeat after me, a battery does nothing for the car after it is running. everybody now ......it will take you days to find someone that that has happened to. dont even begin to say that you know a guy. this has been debated time and time again. Its a possibility and has never actually happened if done right. I personally have over 10yrs experience working on cars and I dont even know a guy who knows a guy. Plus it would only spike when reconnected. plus the regulator will compensate for it. plus if he's putting out 22 volts, unhooking the battery is the least of his worries. I am not going to debate this with you so dont start.

I would have someone recheck the alternators output. You never answered my question from yesterday....Is the battery light on while the car is running? If its not and the alternator is good(voltage and connection) then we need to look into other things. have someone retest the alternator's output.

[theMIJ]

please, don't hate on me for giving prudent advice.




Repeat after me, a battery does nothing for the car after it is running. everybody now ..... Batteries help to stabilize the alternator output, and absorb voltage surges, similar to a capacitor. If a battery didn't do anything helpful for a car's electrical system, i really doubt that Formula 1 cars would use them, since they have alternators, but no onboard starter.


it will take you days to find someone that that has happened to. dont even begin to say that you know a guy. this has been debated time and time again. Its a possibility and has never actually happened if done right. I personally have over 10yrs experience working on cars i've got 9 or 10 years experience working on cars, 6 of them professionally, and while i've never ruined anything by doing it (probably because i don't do it), that's no reason to say there isn't a risk. it's like saying that the 'pull out' method is effective birth control, "if done right", since you've done it hundreds of times with success.
Plus it would only spike when reconnected. false, if you look carefully, you can see that the cable terminal arcs on the battery post whether you're connecting or disconnecting.
plus the regulator will compensate for it. the voltage regulator only regulates the voltage in the field circuit in the alternator, which controls the alternator output. It couldn't "compensate" in any way for a transient voltage spike in the electrical system.
plus if he's putting out 22 volts, unhooking the battery is the least of his worries. true, but let's not perpetuate the falsehood that this is an acceptable practice.
I am not going to debate this with you so dont start.



that's kinda like slapping someone in the face and saying, "I'm not going to fight you, so don't start."

[Jrdeamicis]

Im going with you have a leech in your power system.

[328iJunkie]

+1 on what theMIJ said. Never disconnect the battery with the car running. Very bad idea. Its happened to my E30 and it was veryyyyyyy angry.