Nocturnal-G

So I started my car earlier, soon as the smog pump turned off... I heard a humming from the engine with a burnt smell. Let it run for a little while, checked the voltage via the COMAND menu... voltage would drop to about 12.2, until I gave it gas and it shot back up to 14 volts. Turned the car off, tried starting again and to no avail. with very slow cranking and the lights dimming out as it struggled. Once it stopped, lights came back to normal and battery voltage was normal. I will try starting the car later when I get home to rule out if it's the crankshaft position sensor.

Anyone deal with this problem? Thanks!

desired_speeds

possibly voltage regulator fried?

Nocturnal-G

That's what I'm hoping for!

So I just started her right up... check for fuel pump engaging as it did, cranked no problem. Car gave me a BATTERY/ALTERNATOR warning... went into the COMAND voltage menu to check voltage, it was pretty steady at 11.9-12.1 even while I gave it gas. Hopefully this shortens what the problem could possibly be.

Thank you for the advice guys!

PS. I changed the old battery with an AGM battery this past March, so I don't think it's the battery.

A video of the voltage:
http://smg.photobucket.com/albums/v5...t=IMG_1545.mp4

The warning:

Nocturnal-G

And here's pictures of the alternator's copper wires... If it'll be useful in determining the problem. I replaced the alternator about 2-3 years ago.

Neanicu888

That sounds like your alternator is going. These cars are pretty ' smart ' ,if you can call them that...that warning will show up and will give you a few more days until the alternator ' dies ' completely.
When you've replaced the alternator,did you buy aftermarket? Did you give your old alternator for a new one to receive something like 100$ discount? What I mean is a core exchange... Most likely they sold you a remanufactured one...with those you're lucky if you can get 3 years like you did!

Nocturnal-G

The first time my alternator went out it wasn't pretty... I got on the freeway WOT, soon as I was doing 100-110 I got the warning along with the overcharge warning, the windows fogged up which was weird. Didn't know much on what was going on... I didn't replace the alternator myself. But from what I know the alternator that was put in was a remanufactured Bosch unit. Do they usually go out that fast? I don't like the idea of changing an alternator every 3 years.

Neanicu888

There goes your problem right there :
You didn't change it yourself.
' As far as you know ' it's a remanufactured Bosch unit,but you don't know 100%.
Tell me how much you've payed just for the unit itself,not including the labor,if you can remember and I'll tell you what they've put in there. If you paid 200-300$ and they've taken your old alternator away,I'm pretty sure they put some remanufactured aftermarket unit. You see what they do is,they take old alternators and rebuild them,they rewire and change the outside of it or they paint it to make it look like new. These are all garbage,knockoffs...you're lucky you got 3 years out of it!
If you buy an original brand new Bosch or other top brand alternator,as far as I know these days,they give you lifetime warranty on them,but they cost more.

Nocturnal-G

All together with labor it was about 600-700 as far as I can remember. How's 300 bucks sound for a brand new Bosch unit? That's the best I've found and with lifetime warranty, it's awesome.

Neanicu888

The Bosch unit you've found is a remanufactured one. There's no way a brand new one costs only 300$!!!
The remanufactured units come with 1 year/12K miles warranty,no lifetime.
Here's an example :

http://www.autohausaz.com/search/pro...412@Alternator

To see the difference here's a brand new one :

http://www.parts.com/parts/2000/MERC...ent=Alternator


I searched for MY 2000,I didn't know what year is your car.
But you don't need to spend 900$ for a brand new one,buying a remanufactured Bosch unit is good enough,only make sure IT IS A BOSCH,not something else!!!
Just to compare,here are some crappy remanufactured ones(Except the Remanufactured Bosch unit you see there) :

http://www.partsgeek.com/catalog/200...lternator.html

Nocturnal-G

Whoa... that's weird! The part number for a 2002 E55 is different than the rest.

Yours is AL0766X, mine is AL0789X.

Wonder what the difference is? Perhaps the one in my car is the wrong one? I need to check it out.

Neanicu888

To be honest with you,I don't know if there's a difference. I just see that autohausaz.com doesn't have the one for 2002. I found it here :


http://www.partsgeek.com/catalog/200...lternator.html



It looks like it's running 150 Amp as well...

Nocturnal-G

Yeah I noticed that as well. Thank you for all the help, appreciate it.

cm60k

I think those different #s may refers to the Harness version,, some Alternators comes with a wire with nut to hold the positive current (old version),,

and the other comes with a connector socket that contains "1-2" current (new version).......

ZAYED,,

Nocturnal-G

Ah... makes sense. Thanks Zayed!

Btw, don't know if this issue is related with the current problem but sometimes when I put the key in the ignition it doesn't turn then makes a rapid clicking noise, then turns and starts no problem. Sometimes the EIS doesn't recognize the key either and I turn the key to try to start the car and I don't get anything, usually when that happens I pull the key out... put it back and it fires right up. I do get the occasional slow start as well, with the revs going up to 1,000 RPM. Never really bothered me, so I never looked into it. The key I have is brand new... old one got washed so I'm sure the key isn't the issue. Thanks for all the help guys.

cm60k

Always WELCOME,,

First; check the "Fuel Pump Relay", if it ok, then check the "Starter Overload Relay", mostly from it,, if the problem still presists, that

means, we well go to the "Starter switch", it may some culprit in internal signal & pins,, it depends how bad the switch is,, unfortunately

its expensive part,, im not sure if it can be repaired.....?!?!


1) Starter switch #: "210 545 03 08"



2) Starter Overload Relay #: "000 540 00 72"



3) Fuel Pump Relay #: "001 542 96 19" or some versions comes with "001 542 97 19"



ZAYED,,

Nocturnal-G

Thank you Zayed! If it is any of those issues, the part numbers you gave will be helpful!