Charging problem?

[simpletoy]

Got a toyota with 22r in it with a charging problem. The alternator tested good and battery tested good. Not sure where the problem is. All the connections are good and the ground is good? No idea where the problem is. The charge light does not come on and the just not a clue whats goin on with it. Any ideas?

[Haddix505]

Come on Humpy, how'd u have ur alt. Hooked up using only one wire?

[mike shelton]

check all your fuses first. under hood and in the truck. then check all the links at the box near the battery. mike

[jfiscus]

Where is the voltage regulator in this system?
On some it's in the computer itself & can go bad, causing charging issues.

[blustroker]

sounds like a fuse or a bad ground. also check the wire harness from alt to underhood distribution block.

[93 Krawler]

I had a 81 Toy with the same problem. Everything tested good, even the fuses. Found out by chance that the fuse was sitting exactly between the contacts without touching them. I bent the tabs over a little, and problem solved.

[GPER]

I also have seen an alternator test good and replace it and it was all better.

[simpletoy]

I have checked fuses all are good. I have also researched this and I beleive it is the voltage regulator also. All grounds are good and on clean metal. No loose connections on the battery. I was trying to get maybe a few more ideas before I spend 60 bucks on a voltage reg. that I may not need.

[flatlander757]

What exactly is the problem? Battery dying over night?



You can use a good DMM that has an ammeter function(measure amp draw).

Unhook the negative cable, then see hook the DMM in-line between the cable and the negative battery terminal.

So now all the current is flowing through the meter(you do NOT start the truck like this... you'll blow the meter!).

See how many mA it is drawing... should be pretty minimal... under 50mA in most cases.

I have seen alternator diodes intermittently short out/fail before... essentially they will immediately dump the battery dead in a short period of time randomly over night... Had a Ford Focus and was trying to replicate a current drain that we were NEVER seeing... well after about 4 days of checking it on and off we caught it dumping over 100 amps:eek: The battery will discharge REAL fast when that happens. Generally if this happens, you can catch it by using a temp gun(or your hand) and feeling the alternator's power wire close to the alternator... it will be considerably hotter than anything else around it. Note: This will only be a valid "test" if the engine and everything is the same temp... like sitting overnight or something. You will also need some luck as you need to catch it while discharging or right afterwards.


Another possibility is the voltage regulator as others have stated... what that will do is power the alternator's "field" even though it's not spinning... so it will just use power trying to power the alternator's field.

[simpletoy]

Thats exactly what it does is drain the battery but its quicker then overnight. Finally on the last ride I just ran the truck off the battery no alt at all and rode for like 5 hours on a fully charged battery. Ill have to get a meter to check that out

[flatlander757]

Thats exactly what it does is drain the battery but its quicker then overnight. Finally on the last ride I just ran the truck off the battery no alt at all and rode for like 5 hours on a fully charged battery. Ill have to get a meter to check that out

If it does it consistently(like... every time you shut it off) then it should be pretty easy to feel the alternator wires for excessive heat from it rapidly discharging the battery. Feel the alternator casing for heat coming off of the diodes:thumbup:


Again, do this with your whole vehicle cold, it will be harder to figure out if the engine pre-heats up around the alternator:p Still possible but it is easier to get a good diagnosis if everything starts out at the same temp.

Charge the battery, let it sit for a short while to let it cool if it heated up at all from charging, then put it in the vehicle and put a volt meter on the battery. Monitor the voltage, it should stabilize out around 12.3v when it completely loses it's surface charge, but if you see it rapidly dropping below 12v and continuing to drop, it is discharging somewhere... and will be likely visible in the form of heat.

If you have time to kill, you can disconnect the alternator's heavy gauge positive wire and nothing else(keep the field control wire connected) and see if it drains again in a short period of time.


You're a little ways away but I will gladly help with diagnosing the problem for some wings and beer:beers:

[simpletoy]

Alright did some more researching and the volt reg is on the backside of the the alt. not on the fender well like I was told guess those were the older models. I will be over there tuesday to get all figured out. I need to wire up my electric choke on my weber. Think I will just wire that up to a switch or any other ideas?