[DeTomaso] Interesting ammeter situation.

[JEFFREY COBB]

Mike,
A spastic regulator normally indicates a bad connection.
The high ohm connection is killing the alts ability to smoothly dance power to the batteries dampening function.
Back in the 70s, I would hear a customer complain about his Fiats charging system. 
If they did not fix it then his clutch cable would burn-break up a week or so later. Now no charge, no start and no clutch.
The clutch cable had become the new ground strap, Fiat ground straps were garbage, and give spastic amp flow which then would burn due to its poor connections.

Jeff Cobb- I pad

www.LiveOakConcours.org

On Feb 14, 2017, at 10:51 PM, "B. SEIB" <oldwheel at shaw.ca> wrote:

> Hi Mike
> I would try a known good battery and make sure the ground cables at the
> battery and the engine are good continuous connections. Wouldn't hurt to
> check the continuity of the cable from the output side of the ammeter to the
> battery + terminal too. 
> 
> If that doesn't change anything I think the new regulator may be the
> problem.
> 
> If the battery is not acting as a "ballast" to absorb fluctuations in
> voltage, the ammeter will show it with behaviour like you've seen. (as in
> taking off the positive cable while the engine is running - a VERY bad idea)
> My guess is the regulator is not quite up to the job.
> 
> Good Luck
> Barry
> ----------------------------------------------------------------------------
> -------------------------------
> [DeTomaso] Interesting ammeter situation.
> Mike Drew MikeLDrew at aol.com 
> Tue Feb 14 22:19:28 EST 2017 
> 
> Guys,
> 
> Yesterday I accompanied the new owner of a '74 Pantera from Sacramento to
> his home in San Diego. 
> 
> We almost made it. 
> 
> As we entered the worst of the LA megopolis, the charging system suddenly
> didn't. The am we had been dancing around for hours and it finally
> stabilized deep in the discharge zone. With headlights and fans on, crawling
> in stop and go traffic, it wouldn't be too long before the car quit
> completely so we dove off the freeway into a gas station and then enjoyed a
> two-hour tow truck ride (gotta love AAA premium!)
> 
> Today we started troubleshooting. The new owner is almost devoid of tools,
> but we started by changing the regulator since its cheap. The result was an
> ammeter that now danced violently either side of center. 
> 
> Next suspect was the alternator. Although it was new, it was a standard Ford
> remain and thus probably only 50A. We took it to a nearby alternator/starter
> shop where they rebuilt it and converted to 90A in just over an hour. They
> said it tested good beforehand, but since we were there, why not improve it?
> 
> With the rebuilt ammeter installed, the needle swing was even more
> pronounced, wider at idle, and reducing at about 3000 rpm. 
> 
> Now armed with a recently purchased voltmeter, we tested voltage at the
> battery and found it cranking out 14.3-14.6 volts depending on rpm and
> electrical load (headlights etc)
> 
> After a quick call to SOBill Taylor (bless him!!!!) we reinstalled the old
> regulator to see what would happen.  
> 
> Ammeter jumping stopped, replaced with a constant discharge. Voltmeter
> testing at the battery revealed 12.5 volts--the battery was powering the car
> and the alternator was doing nothing. 
> 
> We reinstalled the new, electronic (as opposed to stock-style mechanical)
> regulator, and once again had proper charging indications at the battery,
> but the ammeter continued its wild ways. 
> 
> I shot a video and stupidly oriented my phone vertically. Only idiots shoot
> videos like this, so my profound apologies:
> 
> http://youtu.be/lLKf2Z23P_Q
> 
> So what do you think the next course of action should be? I have at least
> one extra stock ammeter and several regulators, so I am thinking of loaning
> them to him for troubleshooting purposes. Do any of you have any
> suggestions?
> 
> (No, don't suggest he just bypass the gauge or switch to a voltmeter--a
> voltmeter would not have warned us of our charging system failure and would
> have left us stranded on the freeway!)
> 
> Thanks in advance for any constructive advice (other than to learn how to
> hold a phone properly when shooting a video!)
> 
> Mike
> 
> 
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