Last week it wouldn't start my mechanic said I needed a new battery. Then drove it 600 miles over 2 days. Didn't start it for a few days and now it will not crank over. Supercab, XLT 139".
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2004 Ford F-150 Heritage
Question: Won't crank over
Answer #1patrick mannion from Greg Solow's Engine Room, February 12, 2010, 09:04Master
It could be a parisitic draw on the battery (a load staying on with the ignition off that is running down the battery. You would need an Amp meter disconnect one cable of the battery put your Amp meter in series with the battery cable that has been removed. Note the draw say for example 15 Amps, with the keys out of the ignition, doors closed driver's window down, start removing the fuse links and fuses one at a time until the voltage draw goes away to zero (or near zero). It is that circuit that is causing the electrical draw, then look at a wiring diagram, see what consumers are on that circuit and start to isolate each circuit to see which is the culprit.
It could be a bad or unsecured battery ground cable between the battery and chassis or chassis and engine. Turn on the ignition switch to the on but not run position do you see an icon on the instrument panel representing a battery, if you do not see this battery icon the alternator is not seeing power to allow it to charge. Start the engine does the battery icon go out. A more complex but good diagnostic test is checking "voltage drop" on the battery ground and power cables. You can find a video on how to do a voltage drop test on youtube. Put a volt meter across the battery terminals with the engine off, at rest the battery voltage should be 12.6 volts if the battery is fully charged. Now get a friend to start the car while you watch the voltmeter, the voltage reading across the battery should read approximately 14.6 volts if the alternator is charging correctly.
ReplyMichael Mancini, February 12, 2010, 13:26Rookie
I did change the battery and the rest of the system checked out OK. I forgot to say that. The battery is strong it cranks hard but acts like it is not getting gas.