Major Charging Issue Need Help (1 Viewer)

[jay3253]

Okay, so last year my alternator went out so I put on a rebuilt from Toyota. About a month ago that alternator went out too. I got a brand new one and less than a month later I am having charging problems. I drove from Iowa to my in-laws in PA, my truck charged most of the way out at 13.3V. It would drop into the lower 12V range when we would stop and it was idling. When we were about 10miles from their house my cruise control, A/C and radio shut off and when I got to their house I couldn't restart my truck. I put it on a Battery Tender Jr. overnight and it showed fully charged the next morning. I would put it on the charger every time I drove it and that kept it going. It would always fully charge on the Battery Tender Jr. We drove it back to Iowa and again it charged at 13.3V until we got about 50miles from Iowa when the charge dropped to between 11.9V and 12.2V (battery voltage). We drove the remaining 250miles home with no problems and nothing shut off but I was nervous the whole way. The truck is at the dealer and they have run the truck two days straight and it has always charged at 13.3V. I tested the voltage with my Scan Gauge and then I purchased a charging system tester that plugs into the cigarette lighter they both showed the same voltage. I had them remove the grounds to make sure our Iowa salt didn't screw with them but they were all fine (the dealer did take them off and clean them up anyway).

1999 TLC 183k miles. Sorry this is so long.

On a plus side I did get 18.1mpg on the way back to Iowa and did more than 425 miles to my last tank of gas.

 

[gil12]

I'm no expert, but I'd put in a new battery (no matter what any battery test says) and see if it fixes it.

As a side note. I grew up with 4 brothers, and we all had crappy cars, as well as even crappier parts cars that paired with our respective crappy cars. Whenever our mother heard they weren't starting she would proclaim (even though she hadn't been asked) "it's the battery". We hated hearing it because it often was the battery, batteries cost money, and what teenager wants their mother to be right! : )

 

[jay3253]

Okay, new battery and it is charging at 13.2V now what?

 

[Traditionalist]

Do you have a multimeter? What you need to do is to test for AC voltage (VAC). Test it (at the battery terminals) with lights and fans on at idle and 1500ish RPMs. If you have more than .5 volts AC then your alternator is bad.

Right now, mine is 13.7 VDC and .025 VAC.

 

[Traditionalist]

If you have a normal level of AC voltage, then I would look at the alternator B+ connection, the other plug at the alternator, the other connections that are at the + battery terminal for corrosion and tightness.

 

[nissanh]

Check the alternator signal fuse located at the fuse box mounted right on the positive terminal. Clean the contacts and reinsert the fuse. See whether that fixed the issue.

How tight is the drive belt? Is it slipping?

Is the brand new alternator is OEM or aftermarket?

 

[gil12]

I'm wondering how many amps are getting to the battery. And if there is a short somewhere. The shop should be able to check. With a multimeter it is easy to check for any draw when not running. I'm uncertain how to check for charging amps when running.

 

[94SRUNNER]

I’d take it to an auto parts store and have them test the battery and alternator. It will possibly help narrow your system diagnosis.

 

[2001LC]

Did you grease the battery post & clamps after cleaning them!

 

[jay3253]

Okay, so to answer all the questions.

It is an OEM Toyota brand new alternator installed by the dealer. They are also the same dealer that installed the last reman Toyota alternator a year ago.

The belts are tight and not slipping.

There is no corrosion on the battery terminals or at the alternator.

The battery that I put in yesterday was an Interstate that I will be returning today as the problem still exists. Interstate battery tested the alternator and the old battery. The old battery was good and the alternator was showing lower voltage (about 13.1 or 13.2V) at the battery. The dealer tested the voltage at the alternator and it was putting out over 14V.

Low voltage at idle.

• jay3253
• Jul 17, 2018

That picture was taken after the new battery and new alternator at idle. I will check the AC voltage but for now I think I am going to try and find a new alternator wire from the alternator to the battery. That wire is the only thing I haven't replaced.

 

[2001LC]

You said "no corrosion on the battery terminals". But did you grease them? The post/clamps, if dry, will develop a gary hase (oxidation) that will interfere with its ability to accept a charge. Even new batteries need the post cleaned and greased.

You may also want to test resistance of battery cables (+-). If you've seen any corrosion (blueing) at leeds it may have traveled under sheathing around the individual stains of wires.

 

[Traditionalist]

If it has 14v at the alternator and only ~13v at the battery, then I would agree that you have some corrosion or a faulty wire in between the alternator and the battery. Use sandpaper, a file or even a flat screwdriver to clean the inside of the terminals (where they touch the battery posts) like 2001LC said. It should be shiny with no green or dull gray. Take apart the connections on the fuse panel that connects to the B+ terminal as well and look for the same thing.

It is strange (but not unheard of) that you would get two bad alternators in a row, so I'm leaning toward corrosion or a faulty wire.

 

[jay3253]

The terminals were cleaned by me and by the guys at Interstate Battery there is no corrosion. The grounds were taken off rust and corrosion were taken care of then reattached to the block, the body and the frame. There is no corrosion.

 

[Traditionalist]

Hmm. Another thing to try is voltage drop tests. Put one lead of your voltmeter (set to DC volts) on the B+ terminal of the alternator and the other at the B+ terminal of the battery. It should show little to no voltage.

Also check between the B- terminal of the battery and a good chassis ground, and the chassis ground and the engine block.

Do this with the truck running (obviously be careful!) and the lights on. If you find more than .2 DC volts, you have a bad connection or a wire that can't carry voltage in that location.

 

[gil12]

I have had battery cables that were corroded inside the insulator - that created resistance that did not allow proper amperage to the battery. So I like your idea of replacing the cable.

 

[jay3253]

Okay so all new cables for all my grounds and from the alternator to the battery. At idle I am still getting 12.2 or 3 volts. I have running it now for about 30min to see what happens but last time I looked it was idling and the voltage was 11.8V. I think the bad wires (they were bad VERY BAD) caused the new alternator to go bad. I'm taking it back to the dealer tomorrow and seeing if I can get a new alternator AGAIN.

Am I totally off base here about the voltage? I always got 14.4 or 5 befor the alternator went out two months ago now I can't get over 13.5V. What is everyone else getting for voltage?

@jrmudder92 had this problem can you shed some light for me please?

 

[KillerBox]

Check the alternator signal fuse located at the fuse box mounted right on the positive terminal. Clean the contacts and reinsert the fuse. See whether that fixed the issue.

How tight is the drive belt? Is it slipping?

Is the brand new alternator is OEM or aftermarket?

I changed my Toyota dealership changed out my alternator at least twice before I discovered this fuse on the positive terminal was causing my issues. I bought some Deoxit and sprayed the fuse connector.

Before cleaning this fuse, my voltage was up and down constantly. Now it is a rock steady 14v no matter what accessories that I am running.

The voltage fluctuation was with my OEM Toyota alternator and my 250a DCPowerInc alternator. It is quick and easy to check and maybe to fix.

 

[jrmudder92]

Okay so all new cables for all my grounds and from the alternator to the battery. At idle I am still getting 12.2 or 3 volts. I have running it now for about 30min to see what happens but last time I looked it was idling and the voltage was 11.8V. I think the bad wires (they were bad VERY BAD) caused the new alternator to go bad. I'm taking it back to the dealer tomorrow and seeing if I can get a new alternator AGAIN.

Am I totally off base here about the voltage? I always got 14.4 or 5 befor the alternator went out two months ago now I can't get over 13.5V. What is everyone else getting for voltage?

@jrmudder92 had this problem can you shed some light for me please?

What really helped me were the new wires positive and negative from alternator to battery. And i ditched the Toyota remain alternator and found a new one from a company. I still have a problem ever blue moon, so what ever we figure out Ill be doing it too. I just got a Lexus wiring book in the mail that i will be reading to see what i can find out. I honestly think its one of the three wires off the back of the alternator. Like people have said before something has to be corroded. I was planing on removing the fuse box and looking on the bottom side to see if i could see something wrong or corroded. I'm all game for finding this problem. When I read this book I will update. Unless you have found something new???

 

[jay3253]

They haven't even started looking at it yet but everything suggested here I have been texting to the dealer.

Just to let everyone know the reason the dealer is doing this is that the alternator and charging system is under warranty from the first emergency power problem I had a year ago when this all started.

 

[jrmudder92]

Also seams like heat has something to do with it. I am hoping to figure out something