Re: Battery seems weak
When there is resistance in a circuit, you can find it by touch (heat), or voltage drop. Faulty wiring and loose/dirty connections are the main culprits in a faulty ignition system. Starters and solenoids are often replaced for no reason. Take off all connections, and polish them until they shine, then re tighten. Dont simply look at them. Any wiring with nicks, cuts, abrasions should be replaced. If the wire "crunches" when you flex it, that is also a sure sign of corrosion. And as stated, if it is warm to the touch, there is resistance there.
If you would like to know how to physically test the voltage drop, see the following.
First set your DVM to the 20 Volt scale
Put your POS voltmeter lead on the battery POS terminal and the voltmeter NEG lead on the large incoming solenoid/battery terminal post and give her juice. If the meter reads more than .3 volts, the battery cable is bad, corroded or you have a faulty connection (loose).
Next, connect the POS lead to the incoming large solenoid post and the NEG lead to the outgoing large solenoid post while giving her juice. If the voltmeter reads greater than .2 volts, the solenoid is bad, corroded or has a faulty connection.
Next, connect the POS lead to the outgoing large solenoid post and the negative voltmeter lead to the starter positive post and give her juice. A reading of over .2 volts indicates faulty wiring between the solenoid and the starter.
Finally, connect the NEG lead to the NEG battery post and the POS lead to the engine block and crank the engine. A reading greater than .3 volts indicates a faulty negative cable, corrosion or a faulty connection.
