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Alternator/Regulator question



 
 
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  #1  
Old April 25th 06, 02:48 PM posted to alt.autos.bmw
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Default Alternator/Regulator question

I have a 1994 318i with US specs that I recently purchased from a
private owner and would like a little help from the group to diagnose
an electrical issue.

* The alternator appears to be a 105A Valeo
* Most of the time (but not all the time), I notice a slight pulsating
of all lights - headlights, odometer LEDs, interior lights, etc.
* The pulsating is sometimes made worse by increasing the electrical
loads, sometimes not.
* Every now and then, the backlight for the onboard computer display
will go very bright for 2-3 seconds and then the instrument cluster
will go dead and reset itself.
* Sometimes the check engine or ABS fault light switches come on
briefly and turn off.

Based on posts here and elsewhere, I suspect the voltage regulator or
alternator. So, I did a load test in the car while measuring battery
voltage:

At idle: ~14V
All electrical loads on and at idle: ~12.6V
All electical loads on and at 2000rpm: ~ 14V

Does anyone have any insight into whether it is the alternator,
regulator, or both? Also, I understand the Valeo alternators are not
very reliable. Should one even bother fixing one or just replace it
with a Bosch?


Thanks!

Ads
  #2  
Old April 25th 06, 05:29 PM posted to alt.autos.bmw
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Posts: n/a
Default Alternator/Regulator question

On 25 Apr 2006 06:48:44 -0700, "Daniel301" >
waffled on about something:

>I have a 1994 318i with US specs that I recently purchased from a
>private owner and would like a little help from the group to diagnose
>an electrical issue.
>
>* The alternator appears to be a 105A Valeo
>* Most of the time (but not all the time), I notice a slight pulsating
>of all lights - headlights, odometer LEDs, interior lights, etc.
>* The pulsating is sometimes made worse by increasing the electrical
>loads, sometimes not.
>* Every now and then, the backlight for the onboard computer display
>will go very bright for 2-3 seconds and then the instrument cluster
>will go dead and reset itself.
>* Sometimes the check engine or ABS fault light switches come on
>briefly and turn off.
>
>Based on posts here and elsewhere, I suspect the voltage regulator or
>alternator. So, I did a load test in the car while measuring battery
>voltage:
>
>At idle: ~14V
>All electrical loads on and at idle: ~12.6V
>All electical loads on and at 2000rpm: ~ 14V
>
>Does anyone have any insight into whether it is the alternator,
>regulator, or both? Also, I understand the Valeo alternators are not
>very reliable. Should one even bother fixing one or just replace it
>with a Bosch?
>
>
>Thanks!


The voltage's don't look bad, but given the pulsing you describe, it
does sound like the regulator might be playing up.

However, before you go shopping, check the battery fluid level, clean
up the posts and re connect, then do the same for the battery earth
connection to the body and the engine earth strap.

Dodgy.
--
MUSHROOMS ARE THE OPIATE OF THE MOOSES
 




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