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Abnormal alternator output fluctuations?



 
 
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  #1  
Old May 5th 06, 04:31 PM posted to rec.autos.tech
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Default Abnormal alternator output fluctuations?

I'm now thinking there may be a more pervasive electrical problem
causing the Herky Jerky symptoms (chuggle).
The system voltage always shows up kind of ragged in the scans. Take a
look at this:

http://www.efsowell.us/ed/ParkAve/Fr...2006_04P18.jpg

Here are my notes on the episode shown the
+++++++++++++++
4.18: 12.4 minutes into trip. CC set at 66 mph, maintaining 67, TCC
on. Then
speed (or at least the speed sensor?) suddenly drops to 61. Throttle
opens (as it should
this time!) but seems happy to hold 61 mph for 8-9 seconds, why? TCC
stays on. Battery voltage looks rough throughout, between 13.4-13.6.
There were a few dives in inj. pulse width before and after the speed
fall
off.

suspicions: Since events seem to be preceded by drop in road speed,
could
it be a sudden increase in drive-train resistance? Or, ref voltage
effects
on speed sensor?
-----------------

Does anyone know if this kind of fluctuation is normal on one of
these GM CS-130 alternators?

Ed



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  #2  
Old May 5th 06, 06:01 PM posted to rec.autos.tech
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Default Abnormal alternator output fluctuations?

On Fri, 05 May 2006 15:31:12 GMT, "Ed"
> wrote:

>I'm now thinking there may be a more pervasive electrical problem
>causing the Herky Jerky symptoms (chuggle).
>The system voltage always shows up kind of ragged in the scans. Take a
>look at this:
>
>http://www.efsowell.us/ed/ParkAve/Fr...2006_04P18.jpg
>
>Here are my notes on the episode shown the
>+++++++++++++++
>4.18: 12.4 minutes into trip. CC set at 66 mph, maintaining 67, TCC
>on. Then
>speed (or at least the speed sensor?) suddenly drops to 61. Throttle
>opens (as it should
>this time!) but seems happy to hold 61 mph for 8-9 seconds, why? TCC
>stays on. Battery voltage looks rough throughout, between 13.4-13.6.
>There were a few dives in inj. pulse width before and after the speed
>fall
>off.
>
>suspicions: Since events seem to be preceded by drop in road speed,
>could
>it be a sudden increase in drive-train resistance? Or, ref voltage
>effects
>on speed sensor?
>-----------------
>
>Does anyone know if this kind of fluctuation is normal on one of
>these GM CS-130 alternators?
>
>Ed


I looked at the URL graph for battery voltage, and this kind of
fluctuation is very NORMAL. The voltage regulator isn't designed to
output a signal more stable that what you see on the graph.

In fact, that's about as good as it gets, on a SCANNER. +Real+
voltage needs to be monitored at the battery with a DVM. It will be
higher...from about 13.8 to 14.2

Lg

  #3  
Old May 5th 06, 07:13 PM posted to rec.autos.tech
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Default Abnormal alternator output fluctuations?

In article >,
Lawrence Glickman > wrote:

> On Fri, 05 May 2006 15:31:12 GMT, "Ed"
> > wrote:
>
> >I'm now thinking there may be a more pervasive electrical problem
> >causing the Herky Jerky symptoms (chuggle).
> >The system voltage always shows up kind of ragged in the scans. Take a
> >look at this:
> >
> >http://www.efsowell.us/ed/ParkAve/Fr...2006_04P18.jpg
> >
> >Here are my notes on the episode shown the
> >+++++++++++++++
> >4.18: 12.4 minutes into trip. CC set at 66 mph, maintaining 67, TCC
> >on. Then
> >speed (or at least the speed sensor?) suddenly drops to 61. Throttle
> >opens (as it should
> >this time!) but seems happy to hold 61 mph for 8-9 seconds, why? TCC
> >stays on. Battery voltage looks rough throughout, between 13.4-13.6.
> >There were a few dives in inj. pulse width before and after the speed
> >fall
> >off.
> >
> >suspicions: Since events seem to be preceded by drop in road speed,
> >could
> >it be a sudden increase in drive-train resistance? Or, ref voltage
> >effects
> >on speed sensor?
> >-----------------
> >
> >Does anyone know if this kind of fluctuation is normal on one of
> >these GM CS-130 alternators?
> >
> >Ed

>
> I looked at the URL graph for battery voltage, and this kind of
> fluctuation is very NORMAL. The voltage regulator isn't designed to
> output a signal more stable that what you see on the graph.
>
> In fact, that's about as good as it gets, on a SCANNER. +Real+
> voltage needs to be monitored at the battery with a DVM. It will be
> higher...from about 13.8 to 14.2
>
> Lg


Ed should also measure the AC ripple at the alternator.
Volt meter set to AC volts, red lead on the alternator output
stud, black lead on battery negative.
Anything over 100mv AC indicates a problem.
  #4  
Old May 6th 06, 03:50 PM posted to rec.autos.tech
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Default Abnormal alternator output fluctuations?


aarcuda, is that reference voltage specific for GM alternator, or does
it apply to other brand alternators [e.g. Ford, Chrysler?]


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  #5  
Old May 6th 06, 06:38 PM posted to rec.autos.tech
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Default Abnormal alternator output fluctuations?

if you expect / want a steady read, then you might switch to dc - and
forget all the little factors involving ac current.

mho
vƒe

  #6  
Old May 6th 06, 10:15 PM posted to rec.autos.tech
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Default Abnormal alternator output fluctuations?

Sorry, I don't follow. If you are referring to the JPG file, it is
from a OBD-II scanner.
No AC option.

Ed

> wrote in message
...
if you expect / want a steady read, then you might switch to dc - and
forget all the little factors involving ac current.

mho
vfe




  #7  
Old May 7th 06, 12:22 AM posted to rec.autos.tech
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Default Abnormal alternator output fluctuations?

In article >,
Knifeblade_03 > wrote:

> aarcuda, is that reference voltage specific for GM alternator, or does
> it apply to other brand alternators [e.g. Ford, Chrysler?]


Fits all brands.
  #10  
Old May 8th 06, 06:49 PM posted to rec.autos.tech
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Default Abnormal alternator output fluctuations?


Wasn't it you who responded, ".....probably a shot sensor...." to a Ford
charging system question just a few posts back?......

......which elicited the sardonic response, "Yeah, those Ford alternators
are loaded with sensors.", from aarcuda - a well-respected, professional
technician who is a regular participant in this forum


Your more recent comment in this thread, "....if you expect / want a steady
read, then you might switch to dc - and forget all the little factors
involving ac current"....

.....elicited the following response from the same person.....

"....Why would anyone want to skip an important diagnostic step? Do you
have the slightest idea how electricity is generated in an alternator?
(left you a clue there)....."

You seem to have gone through an amazing metamorphosis......

From someone who makes dumb, uneducated, technically-barren statements
about fuel pump timers and locations, sucking air into EFI systems,
MBTE/Ethanol comparisons, federally mandating acetone/gasoline mix, etc.
and who believed that alternators were controlled with sensors......

.........to someone who THINKS he is capable of giving advice on the AC/DC
sides of alternator charging systems......something he obviously knows
nothing about.

BTW - aarcuda's "clue" is in the word "alternator" which is derived from
the term "alternating current" - which is the type of current produced by
an ALTERNATOR...."ac current" to you.......

.......which is a redundant statement since "ac" stands for "alternating
current" making your statement read, "....alternating current current...".

The MORE you comment, the more you confirm your lack of automotive
technical knowledge.

Unplug your WEB-TV setup and tune back into Springer and Oprah........

.........but, NOT before you've done tonight's homework and studied for your
Math test tomorrow morning.

I'm sending you a 10%, "Frequent Customer" discount card for the Clue Store
I'm opening in your neighborhood.

I've got a feeling you're gonna' be one of my best customers, because it
has become painfully apparent that you currently don't have a single clue.



 




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