[DeTomaso] Alternator blues....

[Julian Kift]

Mike,


I hate chasing these type of electrical problems, but here's some thoughts;


i) Battery going bad (how old is it?), requiring the alternator to have to constantly charge

ii) Some alternator re builders are notorious for units failing, over a 50% failure rate is not uncommon. I had a similar issue with my GT40; on the third alternator we switched to a higher amp 'new' unit and never had a problem since.

iii) It could also be an intermittent short or bad ground

Julian
________________________________
From: DeTomaso <detomaso-bounces at server.detomasolist.com> on behalf of Mike Drew via DeTomaso <detomaso at server.detomasolist.com>
Sent: Sunday, October 2, 2016 9:11 PM
To: detomaso at server.detomasolist.com
Subject: [DeTomaso] Alternator blues....

Hi guys,

Just got home from a terrific weekend in the Sierra foothills; 24 Panteras
(of the 36 scheduled) took part in the Niello concours at Serrano.   It
heaved down with rain for a very brief period, but that rain then turned to snow
which kept the large Reno/Tahoe contingent from braving the summit.
Still, a great time was had by all who attended, and we drove home in splendid
sunshine.

We were driving in Lori's Pantera, which has a flat firewall kit and uses a
GM alternator with built-in regulator.   She drove the car to Vegas this
spring, and the alternator failed while we were there.   At first it started
acting erratic, with the amp needle bouncing around, and then finally it quit
and just showed a partial discharge.   Testing at the battery revealed it
was doing nothing at that point.   We replaced it with another one, which did
exactly the same thing and failed about 50 miles from home.

We replaced THAT one, and the third one has worked fine until today.   But
it probably only has about 250 miles on it or so.   On the way home, once
again, I noticed the ammeter needle behaving erratically, then it quit and
showed partial discharge for many miles, then briefly came back to life and
showed a very strong charge (since we had been running on battery power for
awhile), then discharged again.

Methinks the problem is not simply that alternators are failing, but rather
that there is some sort of fault in the electrical system.   As electrons
are far from my strong suit, I hesitate to start diving it to it blindly.

What say all of you?

FWIW we've got a spare alternator we will be installing tomorrow, which
almost assuredly will work just fine...for awhile anyway????

Mike
-------------- next part --------------
   Mike,

   I hate chasing these type of electrical problems, but
   here's some thoughts;

   i) Battery going bad (how old is it?), requiring the alternator to have
   to constantly charge

   ii) Some alternator re builders are notorious for units failing, over a
   50% failure rate is not uncommon. I had a similar issue with my GT40;
   on the third alternator we switched to a higher amp 'new' unit and
   never had a problem since.
   iii) It could also be an intermittent short or bad ground
   Julian
     __________________________________________________________________

   From: DeTomaso <detomaso-bounces at server.detomasolist.com> on behalf of
   Mike Drew via DeTomaso <detomaso at server.detomasolist.com>
   Sent: Sunday, October 2, 2016 9:11 PM
   To: detomaso at server.detomasolist.com
   Subject: [DeTomaso] Alternator blues....

   Hi guys,
   Just got home from a terrific weekend in the Sierra foothills; 24
   Panteras
   (of the 36 scheduled) took part in the Niello concours at Serrano.   It
   heaved down with rain for a very brief period, but that rain then
   turned to snow
   which kept the large Reno/Tahoe contingent from braving the summit.
   Still, a great time was had by all who attended, and we drove home in
   splendid
   sunshine.
   We were driving in Lori's Pantera, which has a flat firewall kit and
   uses a
   GM alternator with built-in regulator.   She drove the car to Vegas
   this
   spring, and the alternator failed while we were there.   At first it
   started
   acting erratic, with the amp needle bouncing around, and then finally
   it quit
   and just showed a partial discharge.   Testing at the battery revealed
   it
   was doing nothing at that point.   We replaced it with another one,
   which did
   exactly the same thing and failed about 50 miles from home.
   We replaced THAT one, and the third one has worked fine until today.
   But
   it probably only has about 250 miles on it or so.   On the way home,
   once
   again, I noticed the ammeter needle behaving erratically, then it quit
   and
   showed partial discharge for many miles, then briefly came back to life
   and
   showed a very strong charge (since we had been running on battery power
   for
   awhile), then discharged again.
   Methinks the problem is not simply that alternators are failing, but
   rather
   that there is some sort of fault in the electrical system.   As
   electrons
   are far from my strong suit, I hesitate to start diving it to it
   blindly.
   What say all of you?
   FWIW we've got a spare alternator we will be installing tomorrow, which
   almost assuredly will work just fine...for awhile anyway????
   Mike