Problems starting 2002 Sport Trac 4x2

[jimb39]

I hope someone can help me diagnose why I'm experiencing startup problems with my Sport Trac.

At times, I'll get the clicking sound when I turn the key in the ignition but the truck is slow to turn over. The problem started a week ago when it wouldn't turn over at all but would start with a jump. The problem seems to be worse the longer the car sits after shutting off the engine. If I turn off the engine then turn the key to start, it starts like a champ.

I've also noticed if I turn the key and get clicks but no turn over the engine will start if I try a second or third time.

I've checked (and had Autozone double-check) the battery and the alternator and both are fine.

I'm thinking there's a short somewhere that is draining the battery as the truck sits overnight, but I don't know how or where to begin to check for shorts.

Does anyone have any ideas what might be going on?

 

[workman482]

Discharge over time

Before doing anything else you may want to get a second opinion and have the battery tested when it is not hooked up to the vehicle. I've found that a hand held load tester is probably the best bet for finding out if your battery has a bad cell.

One way to see if your vehicle is draining your battery would be to use a voltmeter and check the battery voltage after it has been charged by driving your truck. Check it about 10 min. after you park it and shut the truck off and then in about an hour. Wait another hour and check again. This will let you know if there is drain on the battery from your truck.

Another way would be to disconnect the battery after you park the truck for the night, etc. then reconnect it in the morning to see if the truck starts. (You should also use the voltmeter here to get a reading on the battery.)Biggest problem with this is the trans ecu "forgets" how it supposed to shift and has to go through a relearning period where the trans will feel like it's slipping and sluggish.

Just FYI; the alternator should be charging at about 13.5 VDC +/- 0.4VDC.
at about 1500RPM. If it's less than 13VDC it not charging enough to run the electronics in the truck as well as charge the battery. It also shouldn't charge at more than 14VDC as this can fry the battery if charged at this level for a prolonged period of time.

 

[jimb39]

Thank you, Workman. I tested the battery as you suggested at 10 minutes after turning off the engine, 1 hour later, then 3 hours later. They're wasn't much drain after an hour but the charge went from around 12V at the hour mark to under 11 at the three hour mark. I drove the truck a while to recharge the battery then did as you suggested and disconnected the cables. We'll see what it looks like in the am. Thanks again.

 

[jimb39]

Apparently neither I nor Autozone know how to test a battery. After letting the battery sit unconnected overnight it's down to just over 10V. This is actually the result I wanted as I didn't really want to go through the hassle of tracing the drain. Thanks for your help.