[DeTomaso] smokin Pantera

SOBill at aol.com SOBill at aol.com
Sat Mar 29 13:31:40 EDT 2008


Markus,
 
We can solve this problem.
 
At _http://www.panteraplace.com/Electrical/Power%20Distribution.pdf_ 
(http://www.panteraplace.com/Electrical/Power%20Distribution.pdf)  you  will find a 
very top level diagram, which I will also send to you  directly, showing the 
complete power distribution system on a Pantera. A  key part of the diagram is 
the connection between the alternator, the ammeter,  and the battery. The 
ammeter directly indicates the flow of electrical current  into or out of the 
battery. All the electrical loads in the Pantera on are the  alternator side of the 
ammeter. Thus, when things are working normally, the  alternator provides all 
the current required to operate the electrical loads but  this load current 
does not go thru the ammeter. The only current thru the  ammeter is the current 
entering or leaving the battery.
 
How can you tell if the alternator is working normally? With the  engine and 
all electrical loads turned off, measure the battery voltage. The  battery 
voltage should be around 12.5 volts for afully charged battery. Start  the 
engine, rev the engine to 2,000 rpm with all the electrical loads turned  off. 
Measure the voltage at the battery. The voltage at the battery should be 13  to 14 
volts. The amount by which the voltage at the battery with engine running  
exceeds the voltage at the battery with the engine off is direct measure of the  
charging current into the battery.
 
Any other way to see if the alternator is working correctly?  Start the 
engine, immediately turn the engine off. Start the engine,  immediately turn the 
engine off. This sequence will draw significant  current from the battery. Start 
the engine. Watch the ammeter. rev the engine to  2,000 rpm. The ammeter 
should need near full scale for several seconds as the  battery is being charged. 
Holding 2,000 rpm, the ammeter will start to gradually  come down from full 
scale over a period of around one minute as the battery is  returning to full 
charge. When the battery is has been returned to full charge  the ammeter will 
read slightly to the right of zero.
 
What to do with your car?
 
If this doesn't happen with your car, what can we  do?
 
We know that your battery/ammeter/electrical load connection is  correct 
because when the 
headlights are on, we see the headlight load current being drawn  from the 
battery on the ammeter. Start your engine, turn on the  headlights, watch the 
discharge current on the ammeter,  slowly increase the engine rpm, the discharge 
current should decrease  toward zero as engine speed increases and the 
alternator supplies current  to the headllights. It should not take many rpm to get 
the ammeter to zero. If  the discharge doesn't decrease with rpm, the 
alternator is not providing  any current. If the discharge decreases only a small 
amount, the alternator is  not providing enough current.
 
If the alternator is not providing any current, likely there is an  open 
circuit between the alternator and the ammeter. If the alternator is  providing 
enough current, likely there is a poor connection between the ammeter  and the 
alternator. An open circuit or poor connection on the alternator can be  on the 
ground side as well as the 12V side. Alternators are made of aluminum.  
Aluminum ozidizes in the atmosphere. Aluminum oxide is an insulator. Wire  brush 
the mounting surfaces of the alternator and the mounting bracket so they  are 
shiny. If your alternator has a ground stud on the case, install a heavy  ground 
wire from the alternator directly to the chassis.
 
Let me know how what you find with your tests.
 
We can solve this problem.
 
SOBill  Taylor
sobill at aol.com  






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