Alternator Issues

ktmracer01

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Check the ground connections. Rectifier fails with loose battery terminals. I too experienced the same thing with our Hilux LN106 for a loose ground terminal at the battery. Check the ground at the frame too. Just check all the positive and ground wires.
Hmm.. Will do that. Interestingly now that you mention it, it seemed that the negative on the battery was a little loose.
 
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Hey guys,

So an update, it seems that the alternator is not available and the company cannot find the correct part to build the alternator. I am at a loss and have no idea what to do...
 
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Hey all,
another update.
I managed to get a rebuilt alternator from Japan but the pulley size is smaller than what is on the original alternator. I fit the alternator and it seems to be working but am now experiencing a strange issue.
When driving the voltage keeps fluctuating between 12v and 14v erratically.
Would this be because the pulley size is smaller or do i have another issue.
please help… i have been struggling with this issue for almost a year now…
 
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Hey all,
another update.
I managed to get a rebuilt alternator from Japan but the pulley size is smaller than what is on the original alternator. I fit the alternator and it seems to be working but am now experiencing a strange issue.
When driving the voltage keeps fluctuating between 12v and 14v erratically.
Would this be because the pulley size is smaller or do i have another issue.
please help… i have been struggling with this issue for almost a year now…

Okay I had the Tundra 4.7l that was having the same issue where the voltage meter in the truck was fluctuating and at times it even showed the battery light while driving.

I just replaced the alternator with a new one of the big box parts store. It was pretty much a direct bolt on. Pully size being similar. It was my fix.

One other suggestion is the clean out and replace the battery terminals to be nice and clean. That would help as well in charging your system properly.
 
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So what I am nothing is that on idle, the volt output is 14.15v which is normal and good. Then while driving once the car warms up to temperature the voltage starts to become erratic.
On acceleration, it starts to drop (I can see this on the voltage gauge on the dash) and on braking it returns back to the 14.15v.
Also when I am standing in heavy traffic, the voltage starts to drop towards the 13.5v mark.

It is quite confusing and this is for a new alternator that I fitted about 10 days ago.

Also, there is no change to this behaviour if the lights and A/C are on or off which makes this even stranger.

Any advise?
 
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So what I am nothing is that on idle, the volt output is 14.15v which is normal and good. Then while driving once the car warms up to temperature the voltage starts to become erratic.
On acceleration, it starts to drop (I can see this on the voltage gauge on the dash) and on braking it returns back to the 14.15v.
Also when I am standing in heavy traffic, the voltage starts to drop towards the 13.5v mark.

It is quite confusing and this is for a new alternator that I fitted about 10 days ago.

Also, there is no change to this behaviour if the lights and A/C are on or off which makes this even stranger.

Any advise?
Did you first check out your battery condition? Sometimes the battery is old and needs replacement. 2nd make sure the battery connectors are very clean. If the connectors are old swap them out.

That's the only other thing I can think of other than the old alternator/battery cable. Oh do remember that you also want to make sure your ground cable is also nice, clean and tightly bolted on your car chassis. So some other things to look into if the battery stuff look good.
 
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I have also replaced the battery when I fit the new alternator and a new belt.

Another thing is when the car is stationary and I rev even to 5,000rpm the alternator is putting out 14.15v.

It is only when driving!!!
 
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My original alternator went bad at 250k miles during a road trip far away from home, and I had to get it replaced at a nearest PepBoys shop. The only alternator works for LC they had was a generic brand "Part # 13994" and costs $380. Would this alternator be reliable for the next 100k miles? Too bad I didn't have other options back then 😂
 
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So an update to the issue...

Yesterday when driving home I switched on the rear de-fogger and the voltage returned to 14v and the fluctuations stopped.

The moment I switch off the de-fogger, the voltage starts to do the same thing and reduce on acceleration and return to 14v on braking.

I have now tested this on 3 drives and it behave exactly the same way...
 
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This may be stupid and redundant but have you checked the plug to the alternator itself? My alt blew a regulator and fried all my electronics before I realized. Bought a reman Denso and put it in. When I checked terminal to terminal it wasn’t charging as expected. I took it off, looked it over and couldn’t figure it out. Then I checked the plug and the housing was deformed so it wouldn’t seat properly. I ended up having to replace that connector and it charges fine now. I doubt this is your issue but just throwing it out there.
 
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Hey all,

Thought I would post some info I can across. It may help others that find themselves in a similar situation.

I got this info online from a thread on a British forum.

Apparently, this is the smart charging system that is designed to switch off the alternator when the battery is fully charged so as to save on engine loading which in turn saves on the fuel consumption. This was confirmed by Toyota UK Head Office.
 

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