Originally Posted by
recyclemor
1990 f-150 4.9 L. New battery. Pulled all fuses no change. Meter hooked to neg side battery post to unhooked neg. cable. Shows 8.5 volt draw.
This means nothing.
You need to use an ammeter between the negative post and cable to measure for a drain on the battery. You shouldn't have more than a couple hundred MILLIAMPS of draw. You'll need to pull the bulb for your underhood light, or have someone hold in the switch, everything needs to be off.
Also,
1. What is the voltage on the battery after charging it overnight?
2. What is the voltage on the battery with the vehicle running?
3. Pop off the vent caps on the battery (vehicle not running). There should be six holes with acid showing. Working from one side to the other, stick your voltmeter probes into adjacent holes and measure the voltages (i.e., 1-2, 2-3, 3-4, 4-5, 5-6). They should all measure about 2.1V or more.
Jason