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  • 12-13-2010, 04:18 AM

    Understand Michael

    Queens NY
    BMWCCA# 186796
    86 325es (wrecked by careless driver)
    87 325 (project for life)
    00 540is 6spd (daily driver)
  • 12-12-2010, 01:25 AM

    Re: PLEASE explain your hard starting

    Sounds like a bad starter or bad/dirty solenoid. Could even be the signal wire from the ignition to the starter solenoid. Do you have an aftermarket alarm? sometimes the cheap relays they use to cut the ignition signal can actually weaken the power going to the starter solenoid/relay.

    First check and clean all your starter connections and make sure the engine ground strap is clean also.

    If that doesn't help you need to pull out a multimeter and compare the voltage at the battery to the voltage at the signal wire for the solenoid when you turn the key to start. Should be close to the battery voltage, if its substantially lower that means there's a problem between the ignition switch to the starter weakening the signal. YOU MUST DISCONNECT the signal wire from the starter for this test so the engine does not crank at all.

    You can also jump power from another source directly to the solenoid signal wire and see if the engine cranks any better. This a little dangerous if you don't know your way around the engine.

    Queens NY
    BMWCCA# 186796
    86 325es (wrecked by careless driver)
    87 325 (project for life)
    00 540is 6spd (daily driver)
  • 12-11-2010, 05:45 PM

    Do you have a meter to measure the current drain(m

    when all the modules go to sleep after 16 minutes? It should be less than 30ma (0.030 amps)
  • 12-11-2010, 03:44 PM

    Re: Put it all back together with clean connections (m

    I wonder about a slow drain. I know of trickle chargers, but being in an apartment, it is not an option.

    When all put back together, initially, after starting, the alternator read 11.9 volts, but then slowly increased to about 14.2 or 14.3 volts. So it appears to be doing its thing.

    Gonna drive her a bit more today and tomorrow and see what happens.

    Michael1997 540i Automatic
  • 12-11-2010, 03:40 PM

    Re: PLEASE explain your hard starting

    A slow, half-second crank followed by a half-second pause, then another short crank, another pause, then faster cranking for about a second or 2, then she finally starts. It is not exactly the same every time, but close to this.

    Michael1997 540i Automatic
  • 12-10-2010, 06:43 PM

    PLEASE explain your hard starting

    When you say hard starting do you mean the engine CRANKS and doesnt not turn over OR do you turn the key and the engine does nothing?

    Queens NY
    BMWCCA# 186796
    86 325es (wrecked by careless driver)
    87 325 (project for life)
    00 540is 6spd (daily driver)
  • 12-10-2010, 05:52 PM

    Put it all back together with clean connections (m

    at the alternator and battery. Check the battery ground cable connection to the body too. Then atart it up and read the voltage at the battery with the engine at a fast idle. It should read between 13.6 to 14.2 volts depending on how low the battery is and what accesories you have turned on. If your reading is good you could have a module not powering down and draining the battery or like you said you just don't drive it enough. A trickle charger will take care of that.
  • 12-10-2010, 04:56 PM

    Update: maybe not the alternator?

    I went to pick up a new alternator, different parts store, and asked them the check everything before I bought it. Unfortunately, everything checked out okay. Battery, alternator and starter. So I went to another parts house and they said everything checked out fine. I even pulled the battery out and had them test it in the store test bin. Checked out fine.*

    So I did not buy an alternator, I just don't know if that is the problem or not. I am not sure what to do next.

    The only thing I can come up with is that we bought my wife a car a couple months ago. So now I only use my car for VERY short trips, and maybe I don't drive it long enough to keep a good charge on the battery. Not sure what I can do about that, but perhaps that is the problem.* Gonna take her out for a good, healthy drive every day for the next few days and see if the starting problem remains or disappears.

    Would love to hear some ideas. Thanks.
  • 12-08-2010, 02:56 AM

    Re: This has nothing to do with hard starting

    Well, yes I am blaming my hard starting on the alternator. Auto zone tester says the battery is fine. And the alternator has a bad diode. Ergo...

    I am still trying to figure out why Bentley says to undo the positive jump connector on the engine tho.

    Michael1997 540i Automatic
  • 12-08-2010, 12:29 AM

    This has nothing to do with hard starting

    Bad alternator has nothing to do with hard starting, unless you mean the battery is dead and wont start

    Queens NY
    BMWCCA# 186796
    86 325es (wrecked by careless driver)
    87 325 (project for life)
    00 540is 6spd (daily driver)
  • 12-06-2010, 02:34 PM

    Re: Autozone says bad diode in the alternator

    Okay, lots of info here. Thanks to all. I am going to replace vice rebuild because I don't have the time to let the car sit while I try to rebuild. $209 plus tax plus $100 core charge to Autozone and I will give it a go on Friday.

    The procedure is brief in the Bentley. Almost scarily so. It basically says to disconnect the battery, take off the serpentine belt, remove 3 bolts, unplug the harness and pull it out. Can't be that simple. This isn't my '65 Impala.

    One question, Bentley says to disconnect something on the positive jumper connection on the left side of the engine. If I disconnect the negative lead from the battery, why mess with the jumper connection? Or am I misunderstanding the step? It also says to remove the plastic cover on the left valve cover. Again, why?

    Thanks again.

    Michael1997 540i Automatic
  • 12-06-2010, 12:26 PM

    1 hour job is more like it. I changed on the 528

    and it was less then an hour. The hardest part was to put the belt back alone. If you have a help, that should be a simple job too.

    I reused the belt (less then a year old) but I changed the alternator in search of a TransFailSafe mode.

    Alternator test in Autozone failed while in the car, but once I took it off and put it on the tester it was fine.

    1997 BMW 840CiA
    1990 BMW Z1
    1999 BMW 528iT (Hauler mobile)
    2002 Astro Van AWD
    2003 Nissan 350Z Enthusiast Package
    1987 BMW 535i with 5spd manual (for sale)
    1992 BMW 735iL (needs head and interior)
    1977 BMW 320i (project racecar)
    2007 Mazda CX9 AWD (Wife mobile)
    1998 Yamaha Blaster+Breeze

    1995 850CSI CD00177 (SOLD)
  • 12-06-2010, 10:07 AM
    Craig in Canada

    Bosh -> Bosch - oops

  • 12-06-2010, 09:15 AM
    Craig in Canada

    de nada

  • 12-06-2010, 09:07 AM

    Michael, I'm just the RF riffin photographer. Jim

    is the 'splainer. I didn't understand a word of his post to you except when I saw my name, and said "hey, that's me!"


    P.S. Gracias, Craig, for finding it ;-)
  • 12-06-2010, 09:03 AM
    Craig in Canada

    Re: The diodes and voltage regulator are 2 different (

    I would like to know more about replacing diodes in a Bosch.

    I replaced my alternator in 2006 after mis-diagnosis by my indy (I had no time to deal with a noise issue myself at the time). I've noticed that the replacement rebuilt unit is often "weird". Flickering voltage, even at cruising highway speed, and nothing else seems to be to blame. I'm not positive that it's only the regulator and if the rectifier was modular it would be a no-brainer replacement. Even if they were independent heat-sinked parts that could be soldered in I'd do it - I'm an EE, I think I can handle it even though I don't drive a soldering iron any more.

    I'm hoping to use a Eurodavid writeup to rip it apart some time I'm ready. The bearings are still fine at this mileage, but... One challenge will be that now I can't use the model/age/VIN of the car to know exactly which alt I have. Since it's a rebuilt of "similar application" then there might be differences in the rebuild parts needed versus factory original.

  • 12-06-2010, 08:59 AM
    Craig in Canada

    Here they are

    Eurodavid's Valeo writeup (unfortunately all of his photobucket links are now broken):

    Eurodavid's Bosh writeup:

    We really need to do the PDF thing for writeups. This photo link stuff is getting "old". People like Euro go to all the trouble to do writeups and then changes at downstream sites like photobucket make it useless. And, until the software changes at least, Euro can't just edit the post and fix the photo links. He's got to repost the whole thing with new links.

  • 12-06-2010, 08:22 AM

    My college friends called it "Plug&Socket" school

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  • 12-06-2010, 01:45 AM

    Jim, you're an unmasked EE!!

    Ed in San Jose. BMW CCA member since 1987 (Nr. 62319). Golden Gate Chapter. '97 540i 6 speed. Build Date 3/97. Aspensilber over Aubergine leather.
  • 12-05-2010, 10:01 PM

    Thanks JimLev! Paging EuroDavid, alternator

    writeup please!

    Autozone will order me an alternator for $207 + $100 core. It is a 140 amp, so it looks to be the right one.

    Thank you,
    Michael1997 540i Automatic
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