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Printed Circuit Board/Exciter Replacement Issues

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Old 10-29-2008, 01:29 PM
  #16  
SharkSkin
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Fabio, you're right, it's not unusual for a "good" alternator to act as you describe. Sometimes they stop exciting at lower RPMs, especially when new - there is little residual magnetism on a new alt. Also, very old alternators may act this way for a variety of reasons.
Old 10-29-2008, 10:42 PM
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Chris Hansen
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Again, many thinks for the tips and insights.

I drove the car today for an extended period of time, and it seemed to get better! It now swings up to full charge with just a blip of the throttle . . . maybe 900 rpm. A couple of times when started, it came up to full charge by itself. It seems to keep charging while at idle, although the gauge is jumping around, but now staying over 12 volts.

I think I will hook up a voltmeter somewhere so I can monitor it accurately while I'm driving, and see exactly what is going on. Beats taking the pod out again until I'm sure something needs fixing!
Old 11-01-2008, 03:03 PM
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John Struthers
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Chris,
In addition to the afore mentioned.
Check your body/chassis grounds, some look good but are ...crunchy. And green pad the battery ground
area behind the tool kit.
Could be a gremlin, or a bad new alt. if it keeps bothering you, yank it and have it tested at a auto batt. elec. shop.
Old 11-01-2008, 05:11 PM
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Brian B
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Mine also acts like it doesn't excite right away. My charge light never comes on when I turn the key before I start up the car and my volts read low when I start up until I blip the throttle, then all is fine. When I shut the car down, the light comes on as everything is shutting down.

I also have a Bosch alternator with the exciter resistor installed.
Old 11-01-2008, 05:29 PM
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Alan
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Originally Posted by Brian B
Mine also acts like it doesn't excite right away. My charge light never comes on when I turn the key before I start up the car and my volts read low when I start up until I blip the throttle, then all is fine. When I shut the car down, the light comes on as everything is shutting down.

I also have a Bosch alternator with the exciter resistor installed.
If the light never comes on your exciter circuit doesn't work - an open circuit connection somewhere.

Alan
Old 11-01-2008, 11:01 PM
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Chris Hansen
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Just a quick update . . .

I've driven the car every day this week, and it seems to get better everyday. On a cold start-up, when the idle is a touch higher, it now starts charging right away. Occasionally, when I start the car warm, the charge light is on until I blip the throttle. A slight blip works; I no longer have to rev it to 1,500 rpm for it to work.
Old 11-02-2008, 12:10 AM
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Brian B
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Thanks, Alan.

I'll have to pull the pod this winter and check things out. Any other places I should be looking besides in the pod?
Old 11-02-2008, 02:26 PM
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The connections at the alternator and the CE panel & 14 pin connector near the jump post.

Alan
Old 11-02-2008, 02:30 PM
  #24  
devilinblack
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Thanks to Alan and SharkSkin there's some extensive troubleshooting tips on that exciter circuit here.
Old 11-04-2008, 12:25 AM
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Chris Hansen
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For those interested, here's a photo of the bad printed circuit board . . .

Name:  circuit.jpg
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Old 11-04-2008, 01:50 AM
  #26  
SharkSkin
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Holy crap... Any idea what caused it to delaminate like that?
Old 11-17-2008, 12:08 AM
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Chris Hansen
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Just a quick update. I've been driving the car every day, including stop and go traffic,and it appears to be charging fine.
Old 06-14-2010, 06:24 PM
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tylerpate
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Where did you find the replacement circuit flex board for the instrument cluster?

Thanks,
Old 06-15-2010, 12:45 AM
  #29  
Chris Hansen
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http://www.mailordercentral.com/928i...asp?number=928 641 939 00

Here you go . . .
Old 06-15-2010, 01:54 AM
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Bill Ball
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Fixed link:
http://www.mailordercentral.com/928i...928 641 939 00


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