Hello all, something is going on with the electrical system in my truck -- 1989 302 A/T.

Over the last few days I noticed it dragging a little before it would catch and crank. Then Saturday morning, it would not start without the help of jumper cables so I figured the battery was dead and replaced it. After a series of successful cranks with no drag whatsoever I figured I was good for a few more years.

Fast forward to an hour ago....I went to start it for about the 10th time today (been hauling things all day) and it drug a little. Then when I got home it would not start again without jumper cables. I moved it to the driveway and shut it off/cranked it - and now it just growls at me like the starter is bad.

Things I've done in the past few weeks:
Replaced aftermarket stereo with complete new aftermarket system (used the existing direct-connect wiring harness).
Changed oil and filter, topped off all other fluids.
New flasher - my blinkers started going REAL slow around Tuesday.
New battery and positive battery cable. The PO had a deep cell boat/RV battery in there.

I heard a whining coming from the engine bay the other day; when I popped the hood for a closer inspection, I thought it was coming from the alternator. Could it be that it just pooped the bed?


Thanks in advance for any suggestions.

 

Sure could be the alternator. Most parts stores check them for free.

 

start your truck and pull off the battery cable and if it still runs strong with no battery the alternator is fine. also on the back of the alternator there is a small circle in the center it should be magnetic while the engine is running.

 

do NOT PULL BATTERY CABLES TO CHECK THE ALTERNATOR. on electronic controlled engines the removal of battery cables while running could destroy the electronic controlls. this was an exceptable practice on non electronic engines but not on electronic controlls. a much better option is to have the alt checked at a reputable place.
it does sound like an alt is bad. you can start it and put a voltmeter on the bat and see if you have13 or better volts but thatstill doesnt mean the alt is good it may still not be putting out enough amps. are you sure something isnt on like glove box light or fuel pump relay sticking.

 

Hi, I was wondering how much a voltmeter costs? Also, are they easy to use?

 

You should be able to find a cheap volt meter for $10 or so at Sears, Radio Shack, etc... The more you spend the better unit you can buy, of course. I would recommend getting one that also measures current (amps) so you can do those kinds of tests too. As far as using one, there are 2 leads, positive and negative, very simple.

 

If you're gonna spend more than ~$40, you might as well go for a good one, so look for a multimeter that measures "true RMS". The cheapest Radio Shack true RMS is probably $60, and a low-cost Fluke true RMS (the best) is probably $150. That means that A/C signals are actually measured instead of being calculated based on 60Hz (regular home 110/220VAC). It's really important if you ever plan to use it to measure sensor outputs on your truck, or any other electronic device.

 

Thanks for all the tips, I'll get the alt checked tonight. Still not sure why I did not think of that when I replaced the battery the other day..

 

That's the easiest and most common mistake to make when working on anything. It's too easy to look at the symptoms of the problem (dead battery) rather than what the cause of the problem could be.

Had the same thing happen last fall with my son's car. Dead battery. Charged it. Dead again in the morning. Replaced battery. Dead again in the morning. Tested alternator. Replaced alternator. No problems since.

 

There are lots of things that can draw off the battery when they fail. But, I had an alternator checked out at a shop and they told me it was great. Two weeks of messing around proved that I had a bad dioded in the alternator and it was drawing down my battery over time. But it charged great. Get the volt meter and check for a draw with the ignition off first, then go from there.

 

Had the alt. checked tonight and it was so dead that the machine could not even get a reading. I guess that would explain the dead Bronco about 150 yards from the parts store.

After getting towed home I pulled the bad alt. and went to install the new one. Wouldn't ya know that they gave me the wrong one!! Before I left I even double checked the part number with the guy behind the counter and the one in the box does not even come close to what I removed.

With all this driving without a functioning alt. just how bad am I damaging my new battery?

 

As long as you don't hit any hard bumps and put a charger on it when you get home, it should be fine.

 

an automotive battery is not designed to be deep cycled like what you are doing. if you do this only a few times you should be fine but if you plan on doing this all the time forget it the baterry will slowly meet its death

 

Got everything taken care of last night, including an hour on the charger for my battery. The biggest hurdle was finding an alternator that had the mounting tabs in the same position as mine, it took nine alts and two shops before we found one that fit.

Thanks to all for their suggestions and help.