KGK

Hello everyone!

So I've hit a bit of snag with my truck. The other day, I started the truck, and jumped out to scrape the windshield. When I got back in, the truck was idling really low, and all my dials were flatlined. No warning lights were on the dash, and fan inside was still running. Then I started hearing a beeping noise coming from the passenger side dash, behind the glove box. I pushed the gas a bit to see if I could rev it up, and with a little gas it was ok for a second or two. The dials came back to life, but as soon as i let go of the peddle it started to die again.

I shut the engine off, waited a minute, and tried again. This time it wouldn't turn over, making the same noise as when my battery ran out of juice a couple months ago (replaced the stock battery in December after it wouldn't hold a charge anymore).

I got a boost for my truck, and it started fine. Then about 30 seconds later it started to idle low again, and eventually it just quit.

First thing I did was check the battery. Battery had a really low charge. This lead me to believe there is something wrong with my alternator, since I just changed my battery, and the old battery wasn't holding a charge either.

I get out my Voltmeter, check the cables running from battery to the big 175A fuses, then from those fuses to the alternator, everything fine there. Next I put some charge in the battery (about an hour with a little 2A battery charger), and try to start the truck. It turns over, but when I check I am losing voltage slowly while the truck is on. Eventually the voltage gets down to about 9V and dies again.

Am I right in stating this is the alternator then? I can't really afford any major parts, so I don't want to just change my alternator and find out my truck is still borked.

Anything else I should check?

Oh, I have also checked every single Fuse in both the fuse panel under the steering column in the cab, and the fuse panel under the hood on driver side. My volt meter shows the two 175A fuses are still good near the battery.

Any help would be appreciated!

carbon

Sounds like the alt. You can bring it into autozone and have them bench test it for free. I just replaced the one in my truck and it is a very easy job to do.

jgmerrill

it has to be the alternator. and a good tip to remember is just because it has the right voltage, doesn't mean its generating enough amps to charge your battery. Alternators typically have multiple brushes in them, so you could have a few that are dead.

KGK

Unfortunately, where I live here in Canada there aren't any places I can go that test alternators for free. The cheapest place will charge 100$ to test it.

Thanks for the reply though!

KGK

Well, given alternator seems to be the consensus...

According to Ford, the stock alternator is a 115A. When I ask places like NAPA what they have though, they tell me 90A and 130A. Seeing as I do not have a towing package, and its only a 2 wheel drive, is there any reason I shouldn't go with the 90A instead of the 115A or 130A?

I can get a 90A for 2/3 the cost of a 115A, and if it will do the job, then it is the best answer for me. Any recommendations for this choice?

KGK

Well, good news. I replaced the Alternator and everything seems to be going good.

And, I managed to pick up a 130A for 20 bucks cheaper then the 115A stock alternator.

I'll update this thread again if the problem resurfaces, but thanks for the responses!

Mr. Lima 808

hi i have a 2000 ford f150 xlt , I had changed the battery and tryed starting it up. It didnt want to start. I tried and tried then it started then died when i tried pusshing the gas. Then i could here a winding pitch noise comming from some where. Can any one help me diagnose this problem

lifted98_f150

i had this problem. i replaced my alt. didnt fix it. replaced the positive cables on my battery. nope. replace the 175A fuses. nope. replaced the guage cluster with a junk yard one with about the same miles... maybe a few less and that fixed the problem for a while. when it would get really cold out my battery would appear to not be charging on my volt gauge so i got frustrated and smacked my hand on the dash by the left pillar and BAM battery guage flew up to normal checked voltage at the battery and it was like 14.5 and has been fine ever since.almost 4 years ago now this happened. but it was only when it was really cold out. i still have no explination to exactly why this happened but i can tell you hitting my dash actually worked this time haha