Alternator Cause of Parasitic Drain a 3.slow story

[TX_QtPi]

k, So for the last few weeks I've been chasing gremlins in the Banshee.

About a week after I first got her I had to replace the battery.
I didn't think anything of it as I did get her used and she had been sitting for a bit.

She has been a daily driver since, but things have slowed a bit and after leaving her parked for a day, I found she has a parasitic drain killing the battery overnight.

Did all the fuse pull testing with a multimeter and couldn't find much.

So today I go and use a plain ol test light and did the whole test again.
I found that pulling the wire that feeds the 80Amp fuse to the alternator kills the drain. (test light turns off)

So I'm wondering is this the Alternator going bad or is there an easier, cheaper fix? Wiring, regulator, or something I'm missing, that would take care of this?

No other drains or pulls on the battery were found, so I'm sure this is the culprit.

If it is the Alternator, I'm planning on doing the GM alt mod.
Any suggestions for this?

BTW, Banshee = 91 T4R, 3.0 5-spd, 4x4


Thanks for the help Guys,
Cynthia

 

[fourwd1]

Had the same problem on my Maxima years ago.
One of the diodes in the Diode Trio in your alt is shorted.
A good alt shop should be able to replace it for cheaper than a new alt if you can't do it yourself.

 

[TX_QtPi]

awesome! Good to know. Might have them wind it a little heftier too while they are in there. This was a pita to find, but looks like it'll work out well.

thanks so much for the info and lead in the general direction, didn't even think about an Alt rebuild.

 

[ToyoTech]

highly suggest a used oem alt, reman oem alt, or new oem alt. i have see way too many vatozone alt failing the second they are installed

 

[KidVermicious]

I second that. Alternators and starters are notorious for intermittent trouble. They get returned as cores, and when the remanufacturer can't duplicate the trouble in 10 seconds of bench testing, they get cleaned and painted and sent right back out again to give somebody else intermittent trouble.

It's pretty rare that your OEM alternator can't be rebuilt, and as you note, some shops will rewind it for a little more power while they're in there.

 

[Greg_Canada]

If your alt is OEM, i will agree with everyone getting it rebuilt.
I have had 2 OEM alt's and 2 starters rebuilt and they have worked perfect since. I once swapped a junk oem starter for a parts store rebuild and it would die yearly. Never again.

 

[HiluxSurf SSR-G]

to the OP. May I know how to do the test and specifically where did you place the test light? I also would like to test my alternator.

Thanks a lot!

 

[TX_QtPi]

easy way to do it is to put your test light in series on the neg - side of the battery,

so take the neg battery head off, I used a test light with a big enough clamp to fit the negative post and the pointed end was just wedged in the open part of the batt head.

If you have a draw (drain) you'll see the test light light up. The bigger the draw the brighter it will glow.

here is the annoying part. Start pulling each fuse one by one until you see the light go out. It's easy if you start with the ones under the hood sense they are right next to the battery. (plus you can leave the dome light fuse off till your done and avoid a spike when you open the door)

If none of the fuses under the hood are the ones draining the battery go to the fuse box on the inside. pull one by one till you notice the test light turn off. If you have someone to watch it for you it's make it easier instead of pulling a fuse and popping up to take a look.

The Alternator fuse is tricky cause it is actually bolted on the underside but if the wire is bolted separately on the positive side (the small wire that goes from the batt to the underside of the fusebox) then you can just let that loose and it does the same.

Good luck, it's a PITA... :faint: but it's better than having to jump start it everyday

I'll post pics or a how to if anyone wants, it's not hard to do. Let me know!

 

[HiluxSurf SSR-G]

Thanks QtPi! appreciate the help!

 

[fourwd1]

You an also use an ammeter to measure the actual current drain.

 

[TX_QtPi]

How To Find a Parasitic Drain

I figured it would take me less than 5 minutes to do this since I already know which circuit the draw is coming from and I can show n give examples.

So first, You'll need a multi-meter with a mA setting ($24 at O'Rielly's) or a simple test light ($17, same O'Rielly's).

Multi-meter

Test Light

Then Locate your Battery...

Disconnect the Negative Side Battery cable from the Post and place it to the side for easy access.

If you're using a multi-meter make sure it's in the setting to test for current mA (milli Amp).

Next put the test light or Meter in series between the Negative terminal and the post. (note, if you simply wedge the pointed ends of the test light or meter just enough to make contact it should be sufficient)

test light in series. (sorry for the blurry pic)

Meter in series

If there is a current draw either the test light will light up (the brighter the bigger the draw) or you'll see it indicated on the screen of your meter.

Test light indicating draw (it's lit up trust me, LOL)

Draw indicated on meter

Now that you know there IS a draw, you have to find which circuit it is linked to.
To do this:
leave the light or meter connected somewhere you can see it or have someone help you.

Find your fuse box(es) and pull each one of the fuses and relays one by one until the light goes out or the meter indicates a drop in it's reading.

It's easy to start with the fuse box under the hood since you're there then move on to the one under the dash or in the kick panel. remember to do your relays too
(tip: if you leave the dome light fuse off, the one shown in the pic, you won't get spike or surge in your readings when you open the door)

You'll know you found your faulty circuit when either the light goes out or the meter drops down significantly (depending which method you used)

light off

test meter no current

On mine the faulty circuit was the 80A Alternator link. Since this is bolted inside the under hood fuse box I was able to test it by removing the wire which feeds to it. I have other things tied to My battery so I just removed it form the multi-port head, yours might be fused or simply bolted to the battery separately.

I'm replacing the alternator, with one of these:
89-92 TOYOTA 4RUNNER,PU HIGH OUTPUT ALTERNATOR 170 AMPS
getting the draw/drain issue fixed and getting a little more power.
good luck!

this was on a 91 T4R SR5, V6, 5-spd 4x4 but the process should be the same on any vehicle.

Hope it helps,
Cynthia

 

[HiluxSurf SSR-G]

Thank you!!
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[ToyoTech]

better get a battery tie down before the ps pump pulley puts a hole in the battery and throws acid all over under the hood. dont ask how i know

 

[Steven94]

You should feel lucky it is just your alternator. They are easy to replace and relatively cheap. My last car was a 03 Chevy Malibu and it would also drain the battery over night (which the guy that sold it to me said nothing about). I replaced the battery and alternator with no avail. I then took it to a shop my friend was working at in Flagstaff. It took them two weeks to figure out what was wrong. It turns out that both the computers were fried! I was told it would cost $1000 to replace them and I only paid $2300 for the car.

Here she is getting loaded up after I sold her. I have had a few problems with my 4runner, but I can't explain how happy I am to have a vehicle that starts every time I turn the key.

 

[HiluxSurf SSR-G]

just an update:

Did the alternator test. we didn't find any parasitic drag. however, the electrician discovered that the voltage output was only 12.+V instead of 14.+V. He then checked the IC regulator and found out that it was already dead. Bought an IC Regulator to replace the old one. the voltage is now back to 14.+V




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[Millerad1651]

just an update:

Did the alternator test. we didn't find any parasitic drag. however, the electrician discovered that the voltage output was only 12.+V instead of 14.+V. He then checked the IC regulator and found out that it was already dead. Bought an IC Regulator to replace the old one. the voltage is now back to 14.+V




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Do you have a link to the IC Regulator? I have been having problems with my alternator as well. I replaced the brushes, but the alt is still acting up. When I leave for work, my voltage reads 14.2+, but by the time I get to work (15 miles), voltage is down to 13.4-13.6. Its all over the place while I'm driving...driving me crazy.

 

[HiluxSurf SSR-G]

By link, do you mean the part number? if it is, then here you go:

ToyoDIY.com

PN is 27700-50030 (PNC 27700A in the diagram). It's located towards the rear of the alternator and immediately behind the rear cover. the wiring harness plugs into the IC regulator.

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