Originally Posted by
KDW4Him
The arc means nothing. You actually measured it with the .56 reading on the meter before it settled down to 0.01. It's just all the electronics getting their initial voltage when power is connected.
2.1 what? Amps from our first test set up meter in series or 2.1 volts from our second test set up seeing if the neg cable was good. If it was the voltage test for the ground wire I would investigate that. If you are losing 2 volts with just the cars accys on you are probably losing 5-6 volts when cranking or trying to crank. You may even see the entire 12 volts! We have had several reports of ground wires right at the block being very corroded.
Did the jumper cables or battery ever get connected with the wrong polarity? Meaning the neg cable to the pos term and the pos cable to the neg term?
A battery voltage of 12.7 may still not supply the needed current (read amps) to start the car due to internal resistance in the battery. Or a corroded neg wire.
You have some strange stuff going on with only those symptoms. It's like we are missing part of the story.
Just recently bought car.Don't know much about it and it's history.I got car to crank after exchanging battery .But removed negative terminal while car was running and it died.And yes I do recall jumpers being hooked up incorrect before.Alternator and batt shoot????Thoughts?