2001 BMW Z3 Charging

RUDY A

MEMBER
2001 BMW Z3
6 CYL
2WD
MANUAL
52,000 MILES

Thinking that I had a dead battery after not holding charge I repaced it. A few days later new battery dead also. Charged battery and removed pos. Cable, battery held charge. Disconected cable at alternator and charge held for over 2 weeks until I reconnected alt. Cable. Replaced alt. Lost charge overnight. Had old alt cheched out and tested OK.
I'm lost
Any ideas?
Thanks
Rudy

5 Replies

DOCHAGERTY

MECHANIC
9,601 POSTS

Where did you source the replacement alternator? Where did the old alternator receive the test?

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Monday, August 30th, 2010 AT 5:51 PM

RUDY A

MEMBER
3 POSTS

The new alternator was apudrchased from a reputible recicler. The original was tested by an electric auto shop on a machine

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Tuesday, August 31st, 2010 AT 4:43 AM

DOCHAGERTY

MECHANIC
9,601 POSTS

If there is a key off draw, it needs to be found. And it may or may not be the alternator. The car has to go into a sleep mode, this can take up to 16 minutes. Measure the key off draw, all lids shut and ammeter in series with the battery. It should not exceed 50 milliamps. This could be the car not going to sleep or a door lock actuator keeping the bus communication active and not allowing the car to enter its sleep mode.

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Tuesday, August 31st, 2010 AT 8:30 AM

RUDY A