Fluctuating Charge Light

Joined
Feb 13, 2015
Messages
47
Location
The Netherlands
Hi Guys!

Long time lurker and FZJ80 owner since a year. Fixed a lot of problems with the help of this forum! I will be starting a build tread for al the mods, but first i could use some help.

Just finished a 3500 miles road trip without a single problem. But now that the 80 is back to daily duties I have a charge light coming up. (During the road trip I had a fridge which had no problem keeping cold in very hot weather.)
Sometimes the charge light stays on for a little while, but most of the time it's fluctuating, along with the rpm.

-I checked all the connections I could find and all good.
-Belts look ok. They are Gates belts, already have OEM belts waiting on the shelf.
-Battery voltage with the engine off is 12.45
-Battery voltage with the engine on fluctuates from 12,6 to 14,3
-Engine cracks strong with a short voltage drop to 10,8

My interior lights and headlights have always pulsed a little in rhythm with the engine at idle, this goes away when the rpm's get higher. Now the pulsing is worse and in rhythm with the charging light going on/off. So with more rpm everything pulses faster en with less rpm the pulsing is slower.

This is a reading from the OBD2 port (above voltage reading are all from a multimeter directly at the battery)

The strange thing from this reading is that the alternator seems to do nothing at idle. Only when the RPM is raised the alternator kicks in at around 1250rpm. After that the alternator stays on even when the engine is back at idle. (but it is fluctuating)

I tried to ground terminal F at the alternator (as stated in the FSM) but no change. If I did this correctly this would mean the regulator is still ok.

Could it be belt/pulley related? I have a substantial Front Main Seal leak, but the pulley's aren't oily.
Or are the brushes almost gone?
Or could it be the battery?

In this video you can hear the rhythm i'm talking about. Is this normal or is a bearing giving up?

I hope someone could give me a direction to look. Before I start pulling alternators :)

Thanks!
 

MLX450

 
Joined
Apr 10, 2005
Messages
630
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WA
With all your diagnosis it seems to be related to the alternator. Is it still the original?
 
Joined
Feb 13, 2015
Messages
47
Location
The Netherlands
With all your diagnosis it seems to be related to the alternator. Is it still the original?
I don't have a complete service history. But with the information that i do have i would say it could be the original alternator.
 
Joined
Apr 14, 2016
Messages
1,025
Location
Oregon
Battery voltage without ignition off should be around 12.8.

I'm very happy with my Denso remanufactured alternator from RockAuto. I'd replace the alternator and test the battery. A bad battery is hard on an alternator.
 

MLX450

 
Joined
Apr 10, 2005
Messages
630
Location
WA
Or you can just replace brushes and voltage regulator and save a boat load of money, that is what usually dies VR and brushes
Sounds like the bearings are noisy too. You will need to replace those. I would rather get a reman Toyota or replacement Denso alternator.
 
Joined
Feb 13, 2015
Messages
47
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Thanks for all the responses guys!
I've thought about replacing the brushes and/or the regulator. But if the bearings are shot as well I think i'm gonna look for a full replacement.

But I do find it interesting that the fluctuation in voltage is inline with the noise. Could this be just a bad bearing?
Also the idler pulley does very little, it just touches the belt with little tension. Is this normal?
 
Joined
May 20, 2009
Messages
1,822
Location
Canby Oregon
Thanks for all the responses guys!
I've thought about replacing the brushes and/or the regulator. But if the bearings are shot as well I think i'm gonna look for a full replacement.

But I do find it interesting that the fluctuation in voltage is inline with the noise. Could this be just a bad bearing?
Also the idler pulley does very little, it just touches the belt with little tension. Is this normal?
Bad bearings making you lose constant contact with the brushes
 

chap79

Wheel. Break. Fix. Repeat.
SILVER Star
 
Joined
Mar 20, 2009
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2,673
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Harrisonville, MO
I just went through this. A reman Denso unit from RockAuto with 1 day shipping was $158, including the core fee. A new Toyota voltage regulator and brush holder without shipping was $160. Easy decision.
 
Joined
May 20, 2009
Messages
1,822
Location
Canby Oregon
I just went through this. A reman Denso unit from RockAuto with 1 day shipping was $158, including the core fee. A new Toyota voltage regulator and brush holder without shipping was $160. Easy decision.
I went to a local Auto electric battery place and got both for about $30
 
Joined
Feb 13, 2015
Messages
47
Location
The Netherlands
I've got the alternator tested at a shop and it was indeed the culprit. Because it was the original alternator i've got it remanufactured and I just put it back in. A steady 14,5 voltage, no more battery discharge light and no more flickering lights!
Thanks guys!
 
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