Alternator Sometimes Charging

[SNORKALUFAGUS]

I am not one to quickly ask for help without doing a search and also spending hours trying to figure my car out. This one has me a bit frustrated and I'm afraid I am becoming a very unpleasant person to my family at this point lol.

Problem:
The Alternator sometimes charges and sometimes doesn't. I turn the truck on start driving and the voltage light comes on. I stop at the light .... turn the car off turn it back on and it is fine again. Sometimes i have to do this about 5 times to get it to start charging (or at least get rid of the light and see the little volt meter go up). When the truck is charging the voltmeter reads 13.4 consistently ... When it stops charging it reads 12.3 and starts dropping to 12.2.

I start driving and eventually the light comes back on. Today I drove home about 26 miles with the light at night with my stereo on and my lights on. I was ASKING for it to fail but it just keeps driving. I wanted it to like die so that way I could be like AHHHHHHHAAAAAAAAAAAAAA but it just keeps running!!

I have started the car and disconnected the battery to see what would happen and the truck keeps running.

Parts:
New Battery
New Alternator
New Fuses (Alt-S 7.5, ALT 140amp, JB NO.2 100amp) @ Positive Battery terminal
Changing fuse 51 tomorrow
New Battery Terminals Marine Grade

Important info:
No Amps
No Winch
No Lights
No Aftermarket Radio or Electronics of any sort
iPhone Charger only


When did it start or HOW:
I was driving to the beach and my lights dimmed and it shut off about 8 miles from our camping spot. I didn't even play any games... I got a new battery and new alternator. I put it all on and it worked fine no lights no nothing got home with no problems about 160 miles. (maybe ran on battery the whole time ??? I have no clue)

Its almost like it charges just enough to keep the battery at 12v but not enough to keep the light off in the dash.

Summary:
Truck charges sometimes, when it stops charging I turn the truck off then on and then it starts again .... i repeat this all the time just to be safe. I replaced a lot of things and still having an issue.

 

[YvesNL]

I would take out the FSM and trace all wires and connection from alternator to battery/fuses/power distribution.
Measure all connections with a multimeter, wiggle the wire, make sure all cabling still is low impedance.
Breaks in the wire will most likely be close to the terminals or at zip tied or vibrating points.

Make sure there isn't any corrosion on connections and fuses, also check for cracked or slightly damaged fuses.
If you're not sure measure impedance or change fuses.

On an Audi 80 I had an intermittent charging problem, turned out to be a faulty wire.
Ohms changed from low to high while wiggling the cable. Cable was also getting hot in one spot.

A quick look with an IR camera at wires could also expose these problems.

 

[vman07]

Check all your motor to chasis/frame grounds, not sure how many are on the 100, but the Toyota 22re has 4 and if any of them are poorly grounded you could have any number of electrical issues...

 

[YvesNL]

Check all your motor to chasis/frame grounds, not sure how many are on the 100, but the Toyota 22re has 4 and if any of them are poorly grounded you could have any number of electrical issues...

Vman07 is right, forgot to mention this.

Check these connections, and also measure ohms on these connections.
They might look good, but fail if you measure resistance (Ohms).

 

[SNORKALUFAGUS]

I am going to check today and I'm going to replace as much as I see fit. I don't mind replacing things as this stuff is 17 years old already and give me piece of mind. This is not a budget fix I'm willing to get in there and freshen everything up. Ill do things one at a time that way i can let anyone that might come up with this issue later will have an idea of where to start also.

 

[AimCOtaco]

Sounds like a possible load relief relay issue?

A load relief relay will prevent the alternator or other loads from running while the starter is cranking. It may interrupt the climate fans, headlights, alternator field, etc to keep max power going to the starter. I can't say for sure that the 100 interrupts the alternator or charging circuits while cranking but if it does it would make sense that re-starting a few times would bring it back as you'd be cycling any load relief relays when you do that.

You may already be familiar enough with the schematic to rule this out but it seemed worth a mention at least.

Good luck with it.

EDIT: maybe also change out the alt fuse at the battery terminal while you're at it, it's the sense line.

 

[SNORKALUFAGUS]

I actually am not familiar at all. I am doing my best and trying to keep my head clear and not get frustrated. I am doing one thing at a time at the moment and driving it. Then doing something else ... and driving it.

How would I go about testing the load relief relay? Where is it? Ill do some research in a second and see myself but for others that run into this it would be nice for it to be all on the thread and not just in my head.

At the moment the truck for the last 25 miles has been just fine AFTER i took the fuse out (51 NO.1 Charging) and had to put it back in because auto zone did not have the fuse in stock. I put it back in and it has not given me a light yet. Im still going to change it out once I find an 80 amp fuse.

Im going to find this issue !!!

 

[hoser]

My guess is your "new" alternator is defective. At startup, my voltage at the battery reads ~14.2V

 

[SNORKALUFAGUS]

Hoser....

I think I'm on the same page with you on this one..... I have replaced all fuses all connections are clean. Battery is new. I have connected disconnected and connected everything twice.

I am going to pul the alternator tomorrow evening and get a new one.

I have the original one still. I might take it to get built in the AM should be ready by the evening.... I will let you know tomorrow.

I took off the skid plate and followed all the wires to see if anything was melted or frayed and everything looks solid. I think my alternator took a dump and then the new one was defective... If thats the case thats a series of very ridiculous events!

This is super frustrating .... My truck works but just doesn't work like it should!

 

[SNORKALUFAGUS]

I mean what would cause it to start charging again when I shut the truck off and turn it back on???

This is the part that makes me like WTH .... when it is charging the volts are right everything is working right ,,,, then it stops working.

I then turn the truck off and on ... then it starts working again for a little while.

 

[SNORKALUFAGUS]

Ok just wanted to close out this thread with the solution. I see so many threads that ghost with no solution and I don't want this to be one of those.

The problem was the ground on the alternator. It had frayed and just burnt on. The nut was welded on to the stud. I think a combination of things caused this to happen. The connection might have came loose making sporadic contact with the wire.

The solution was to pull the entire damaged wire and replaced with a new one.

Things that I had to get:
-4 gauge wire (black) about 7.5 is the right length
-Crimp Connectors for both sides. (Napa had everything)
-Heat Shrink
-Electric Tape

The alternator wire runs from the alternator all the way to the fuse box right beside the battery. It is the first connection on the fuse box on the back side. The wire runs up the wheel well and on top of the radiator via a plastic sleeve. You will have to remove all the clips. I got away with leaving in the radiator clips and pulling the wire out and feeding the new wire through that.

After I had everything put in where it needed to be then I crimped on the ends. If you do this first it will be hard AF to feed the wires. When doing all of this be care full not to mess up the alternator plug wires which are those colorful ones in the picture. Those will need to get stuffed back in the plastic sleeve also.

After it was all stuffed in the plastic I put new electric tape on everything to make sure nothing ever comes back out. I put the clips back on the sleeve and secured them to the fire wall and the alternator bracket.

None of this is hard it just takes patience. I replaced everything on this system so I hope its fixed for good.


Thanks for all the help guys.


I did all of this During Hurricane Harvey !!!! LOL