masamu6012

Hi everyone, I just bought a 1989 Mustang GT. I started it up a few times and it started fine, maybe struggled a little bit, but I figured that it was because it hadn't been driven in over a year. So I drove it home (about 100 miles) and now it won't start. The lights come on and everything but it just won't turn over... Is this possibly a bad alternator?

jesse1125

Do the lights dim when you try to start it? Have you tried to jump start it? Do you hear a clicking sound when you try to start it?

We need more info on what is going on.

You may just have a bad battery but you can't troubleshoot the alternator until you get it running.

Start by jump starting it.

MythEyeLess

If you have a bolt meter check the battery. It should have 12 volts if it doesnt that's why it wont start. If when you turn on the car the voltage doesnt go up to around 14 volts then ur alternator is bad.

masamu6012

The lights do dim a little and also I do here a little clicking sound. I'm going to try to jump it as soon as I get out of class. I did turn it off halfway home and I had to push start it because it had already ran out of enough juice to get it started. But wouldn't the lights and everything else not work if the battery was bad? I had the headlights on the whole way back and it was a 2 hour trip...

masamu6012

I did look at the voltage when I was trying to start it too. It was unusually low, I think around 8 volts...

mustangGT86_05

Not necessarily true, a battery can show 12 volts and have 0 amps and that could be the cause. Voltage is the flow of electrons, something like 6.6 billion through a given point, and amps are pressure. But I have watched low voltage batteries start cars

Does your battery light come on while driving? If not, does it light up the self test when turning the ignition on? If it does and stays off while driving chances are the alt is pumping juice. Now with that said, it is possible the voltage regulator which would be overcharging the battery causing premature failure.

My suggestion, starting and charging is such a gray area you can't ask a forum and get a direct solution. Do the smart thing and take the car in to be tested, its usually free to have done.

mustangGT86_05

Oh and btw, testing voltage while starting will drop voltage, normally around a high 9 or 10 volt range, so it may just be a little under charged or it may be bad. There is also a possibility of poor connections. If you want to test, do a voltage drop test if you know how and your readings should be close to 0, its ok if its a little off but if you read around a half volt or more at a given point it needs cleaned/tightened/whatever to fix it.

mustangGT86_05

Oh and one more thing I forgot...wish I could edit posts lol a regular alternator is controlled to put out 14.5 volts when at full capacity. 16 volts is WAY too high, your voltage regulator at that point is bad. It is ok to see figures around 13 some volts, simply means it isn't running a heavy load.

AdderMk2

you can... click the edit button at the bottom of the post...

mustangGT86_05

Not on a cell phone unfortunately, mobile version doesnt allow it, but that's besides the point.