Alternator Question/Mechanic Help

WeberWho

I replaced my alternator yesterday. My truck lost all power yesterday when test driving it after replacing the alternator. I drove the truck home and shut it off. I tried to restart it and I had a dead battery. I went and bought a new battery and it fired right up. I drove it 10 miles home without any issue. I started it up this morning and it was really cold outside. No problem. I let it idle for about 10 minutes this morning while pulling out and starting my smoker. Next thing I hear is my truck shut off. I go and try to restart it and I have a dead battery. My truck has died twice now since I've installed the new alternator. It has drained two batteries. What's the chances of the alternator being bad out of the box? I'm not sure what else would be draining the battery but it started with no issue this morning. 

SGH

WeberWho said:
 What's the chances of the alternator being bad out of the box? 

It’s definitely possible. I have got 2 bad ones in a row one time. In all these years it’s only happened to me that one time. But I know it can definitely happen. 

ColtsFan

The first test drive on the bad battery could have killed the new alternator. There may also be a fusible link or fuse somewhere depending on the vehicle. Throw a voltmeter on the battery, assuming it’s charged, and see what’s the voltage going into the battery while running is. Should be > 13.2 and below 15 at ~2k rpm. Definitely a possibility of getting defective parts especially if shopping at a “discount “ parts store 

1voyager

Most likely the belt is too loose. 

Did you replace the belt as well?

Did you notice any screeching noise or the smell of burning rubber prior to replacing the alternator?

Is the belt for the alternator only or is it a serpentine belt?

MaskedMarvel

Voltage regulator?

WeberWho

Thanks guys. When I get home I'm going jump it and see what kind of reading I'm getting on the alternator. I tested it a few months ago and it tested good with the old alternator. My headlights would go dim some days and other times it would be fine. (Battery indicator light on my dash would appear from time to time). I just assumed it was my alternator going bad although it tested good at the time. Two dead batteries now since I've installed the new alternator. 

What I might do is install the old alternator back on and see what kind of issues it has. The old alternator never chewed through batteries or shut down or kill the power.  

WeberWho

I got the truck running and the alternator is reading out 11.74 while running. 

kl8ton

WeberWho said:

I got the truck running and the alternator is reading out 11.74 while running. 

Isn't it supposed to be more in the 14 range? At least 13?

nolaegghead

WeberWho said:

I got the truck running and the alternator is reading out 11.74 while running. 

That’s either a bad alternator or your voltage sense wire to the regulator is not sensing battery voltage correctly or there’s a problem with wiring.  Does the alternator have a built-in regulator or is it external?  Where are you measuring the voltage?

nolaegghead

Charge up your battery and take it to autozone for a test.

WeberWho

I'm thinking it's the alternator. The battery was reading 11 something before starting the truck. I believe it should be somewhere between 13.5 - 14 while running. I'm not getting much if any from the alternator. It should jump up a couple volts with the alternator. My best guess anyway at this point. 

WeberWho

nolaegghead said:

WeberWho said:

I got the truck running and the alternator is reading out 11.74 while running. 

That’s either a bad alternator or your voltage sense wire to the regulator is not sensing battery voltage correctly or there’s a problem with wiring.  Does the alternator have a built-in regulator or is it external?  Where are you measuring the voltage?

From the battery. 

Ozzie_Isaac

While charging usually 14-14.3

Most likely an integrated voltage regulator.  Sounds like alternator is bad, or like Nola said, a wiring issue.

alaskanassasin

Does it have a exciter wire? Sounds like it’s trash though 

WeberWho

I feel a little better. The alternator failed 2 of the 3 tests when testing it.



I made sure to get the new one tested before leaving. 



What a cluster. Hopefully this alternator gets me better results....

lkapigian

WeberWho

Alternator is reading 14.02

What a relief. Hopefully nothing goes haywire from here on out. My wife blew a right rear tire last night. So she's on a donut until tomorrow morning when everything opens back up. So it's nice that the truck is back up and running. Plus I dumped my last half bag of briquettes in the gravity feed smoker for my pork butts this morning and I'm nearing the end. Perfect timing!

lousubcap

Sometimes "When it rains, it snows."  At least you are on the upslope now!

SGH

WeberWho said:

I feel a little better. The alternator failed 2 of the 3 tests when testing it.

That answers the question you asked about getting a bad one out of the box. 

I made sure to get the new one tested before leaving. 

Bingo 👍

What a cluster. Hopefully this alternator gets me better results....

One can only hope 🤞 

SGH

All kidding aside I got 2 bad ones in a row years ago. You talk about aggravating. 

WeberWho

SGH said:

All kidding aside I got 2 bad ones in a row years ago. You talk about aggravating. 

Yeah that wouldn't have been very fun. I wanted to be certain before making the trip back home that the new alternator tested good. I'll make sure anytime in the future when purchasing an alternator that they get tested before purchasing. It only takes a few minutes to run through their machine. Well worth the time. 

WeberWho

I took it for a test drive and I could feel it misfire in certain gears. Long story short I had a misfire issue a few months back. (Turns out I was sold the wrong coil a year earlier.) I felt a slight misfire last week but figured it maybe had something to do with the alternator. My fears grew that it wasn't the alternator as it just tested good. I was happy to see a service engine light come up on the dash. I didn't get any service engine light last week when I first noticed the slight misfire. So I was able to pull up a code on the diagnostic tool. It pulled up a P0301 code. Which I knew was the first cylinder with that code. I go to pull the cap off the spark plug and I feel little resistance. Yes!!! I'm guessing the plug or wire must have got bumped when I changed the oil last week on the truck. The mechanic ran the wires kind of funky to the coils and the 1st cylinder wire is right next to the oil cap. When wrestling the alternator out I must have pulled or bumped the cap even more where it was almost all the way off the spark plug. I pushed it back down on the spark plug, erased the code, and took it out and put some miles on it. The old girl gets up and goes now! Finally!!!

alaskanassasin

hats off to troubleshooting it yourself.

kl8ton

alaskanassasin said:

hats off to troubleshooting it yourself.

No doubt. @WeberWho almost had to get his furnace repair lady to take a look at it. 

WeberWho

kl8ton said:

alaskanassasin said:

hats off to troubleshooting it yourself.

No doubt. @WeberWho almost had to get his furnace repair lady to take a look at it. 

She did prep a couple pork shoulders this morning when my day took a 180 turn after my truck randomly shut off. 

WeberWho

Update on the alternator....

My current alternator is no good. It lasted 11 months. O'Reilly's took back my alternator since it came with a year warranty. To be completely honest I didn't think I had much of any shot of getting a replacement alternator under warranty as I didn't have a receipt. They couldn't find my original alternator purchase but they did see on their computer that I had an alternator warranty replacement within the last year. (The first alternator was bad out of the box) 

O'Reilly's said they could have an alternator available for pick up around 2pm yesterday. So I had to wait 3-4 hours for the new alternator to be shipped in from their warehouse. So I stop back in O'Reilly's and grab my alternator. Before heading out the door I ask O'Reilly's employee if they could run an alternator test on it. (Just to double check to see if the alternator is good from the start. I learned my lesson after my 1st alternator.) You can only guess how this ends.....another bad alternator. O'Reilly's apologized and refunded 100% of my money back from 11 months ago when I purchased the original alternator. The O'Reilly's employee was absolutely fantastic. I think she was more frustrated than I was about the whole situation. No hard feelings with O'Reilly's. 

So I called around and found another alternator but this time it was AutoZone. Unfortunately this was an 1.5 hour roundtrip for it. So I make the trip and grab the new alternator. I also have them test the alternator before heading home with it. It checks out! So I go home and install the new alternator. I go and start the truck and I hear an awful noise. Ugh!!! I remove the belt and try to spin the pulley on the alternator by hand and I feel resistance. Yep, bad bearings. You can't even make this up!!!

I just received a call that my 5th alternator has just shipped into my local AutoZone to be picked up. This is getting to be a little redundant....

lousubcap

@WeberWho If nothing else you are to be commended on your dogged persistence.  You have much more patience that would I at this point.  Here's to  getting this resolved this year!

Happy New Year-🥂

Cap

GregW

Is there another parts supplier that has better quality alternators? Perhaps Napa? buying their best grade?
For me, I really didn't want to be under the vehicle the first time, so I really wouldn't be happy the second time- not to mention five times.

This bad alternator story seems to be all too frequent with parts suppliers these days.

hvhunter

SGH said:

WeberWho said:
 What's the chances of the alternator being bad out of the box? 

It’s definitely possible. I have got 2 bad ones in a row one time. In all these years it’s only happened to me that one time. But I know it can definitely happen. 

I had that happen to me once.  The new one gave me same symptom as my bad one. 

WeberWho

GregW said:

Is there another parts supplier that has better quality alternators? Perhaps Napa? buying their best grade?
For me, I really didn't want to be under the vehicle the first time, so I really wouldn't be happy the second time- not to mention five times.

This bad alternator story seems to be all too frequent with parts suppliers these days.

I have a feeling that a majority of them are coming from the same rebuild manufacturer but with each stores own sticker on them. Napa unfortunately didn't have any alternators in stock and would have to be ordered in. (16 year old truck) So I'm pretty limited on what's available. The employee at AutoZone said that 10% of alternators are bad straight out of the box. I'm way over that 10% chance. 

WeberWho

The 5th alternator was the charm. Back in business.