Charging Issues

[grayfj62turd]

My 89 FJ62 is having some starting issues. Slow cranking but the battery is new. I noticed the alt meter in the dash was kinda wonky and took some pics at idle and then around 1500 rpm. Is the alternator charging?

 

[FJ Silver]

First thing to check is the actual voltage of the battery when running and when not running.
And the voltage at idle + at 1700rpm.
It could be the gauge in the dash, mine acts up sometimes, but I have my actual voltage in an aftermarket gauge cluster to erase doubt.

Check the voltage output on the back of your alternator as well. If there is a discrepancy between what the battery is showing and what the alternator is putting out, you know its the fuse or cable in between.
Alternators aren't hard to find. Even Rockauto has some options:
1989 TOYOTA LAND CRUISER 4.0L L6 Starter Motor | RockAuto - https://www.rockauto.com/en/catalog/toyota,1989,land+cruiser,4.0l+l6,1276624,electrical,starter+motor,4152
OEM / refurbished is always best, just google around.
Its a pretty easy job, swapping out these guys.

 

[OSS]

Maybe just remove the battery clamps, clean them up and tighten them back on. See if that helps.

 

[SteveH]

Put a VOM on your battery terminals under these conditions:

1. Engine off - should read 12.62v-ish
2. Engine running - should read 14.2v-ish
3. Engine running, headlights, heater fan, and rear defroster on - should still be over 14v

This will give you an idea of your battery's charge state, as well as if the alternator is working at all and how it handles load. After this, you can do a deeper dive on what else may be wrong. As @OSS pointed out, be sure your battery terminals are clean and tight.

 

[FJ Silver]

Put a VOM on your battery terminals under these conditions:

1. Engine off - should read 12.62v-ish
2. Engine running - should read 14.2v-ish
3. Engine running, headlights, heater fan, and rear defroster on - should still be over 14v

This will give you an idea of your battery's charge state, as well as if the alternator is working at all and how it handles load. After this, you can do a deeper dive on what else may be wrong. As @OSS pointed out, be sure your battery terminals are clean and tight.

Above 14V having all those accessories running at idle is normal?
If e.g. 13.6V at idle or higher RPM, would that indicate the voltage regulator going belly up or brushes? or?

 

[OSS]

Low voltage with alternator spinning and battery charged and no accessories on = alternator needs to be rebuilt or replaced with a rebuilt one. Can’t pinpoint exactly what the issue is initially just by low voltage output.

 

[FJ Silver]

Low voltage with alternator spinning and battery charged and no accessories on = alternator needs to be rebuilt or replaced with a rebuilt one. Can’t pinpoint exactly what the issue is initially just by low voltage output.

Gotcha, thanks.
When I have my Redarc DC to DC charging my house battery at 25Amps, I'm getting about 13.6V when driving / higher RPM.
I hardly ever see numbers above 14V even when batteries are full and no accessories.