1979 FJ40 OverAmp Issue

Joined
Aug 9, 2022
Messages
3
Location
Dumont NJ
Greetings, I am at my wits end and decided to ask for help, cuz I need it. Let me start at the beginning. I acquired the FJ running as is and was always over amping, so much so that it killed two batteries. I decided to spend some time and study the issue. I discovered a crazy adaptation of a 4 wire Fors Voltage regulator and an amount of splicing in the wire harness that was INSANE and UNSAFE.

I decided to to gut the harness and start all over again, cuz damn! (Will attach pics) after some research…I have the original 3pin plus battery alternator which was bench Tested and passed with flying colors. We also are equipped with the double rectangular indicator dash light. Ebrake/no charge which calls for the 6 wire voltage regulator. I followed the schematic and the following happens.

The no charge light is always on even when running and charging, if I connect the “e” wire on the VR to the “E” (communal ground from alternator) the wire heats up super quick. I disconnect it and the VR “L” wire to the lamp as well but continues to overcharge even when disconnected.

Output at idle 13.64v
Output at full throttle 17.09v
Ammeter reading at idle -45amps
Ammeter reading at full throttle +infinity

Not sure if the ammeter os working properly. Have to tap it once in a blue to get it to read.

(Ammeter is simple only magnet no resistor)

Double checked the connections from alternator to Voltage Regulator.

Battery nut to ammeter to starter to battery
“F” alt to “F” vr
“N” alt to “N” vr ( what does “N” do?)
“E” alt to “E” vr (which burns the wire of o keep it connected)

On the vr side…..

Condenser/ignition (same post) to ignition
“L”vr (which is oddly soldered to the vr chasis) to the ground side of the the “no charge” indicator lamp (which keeps the light always on. (I keep in disconnected)
“B”vr to the battery (constant 12v feed)

Help me Obiwan Kenobi, you’re my only hope.

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Joined
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You never mentioned it the voltage regulator was tested. You also didn't state what gage wire was used for the "E" connection. If the voltage regulator is out of spec it could cause issues. If the "E" wire is to lite it will heat and possibly burn.
 
Joined
Aug 9, 2022
Messages
3
Location
Dumont NJ
You never mentioned it the voltage regulator was tested. You also didn't state what gage wire was used for the "E" connection. If the voltage regulator is out of spec it could cause issues. If the "E" wire is to lite it will heat and possibly burn.
The voltage regulator wasn’t tested, I bought it on eBay and was new, but who knows how long it was sitting on a shelf.
The “E” wire (ALT thru dash to passenger side 10 gauge but the “e” wire on the VR is 16. Very strange

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ToyotaMatt

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The voltage regulator wasn’t tested, I bought it on eBay and was new, but who knows how long it was sitting on a shelf.
The “E” wire (ALT thru dash to passenger side 10 gauge but the “e” wire on the VR is 16. Very strange

View attachment 3082517


- you need a OEM Voltage Regulator for starters ,

- then you need the correct in-put plug connector

- im seeing you have terminals touching inside that green connector with each other ?


- if so this is your issue , diagnoses and cause ,


see below links for the correct remed'ies


you can't simply insert 6 loose wide female spade terminals all bunched up together like this ?


you also need the CORRECT alternator input plug connector for a FEN unit .........












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Joined
Aug 9, 2022
Messages
3
Location
Dumont NJ
Maybe this thread will help.
This is great! Thank you. I’ll grab those VR PLUGS maybe from SOR or somewhere similar. The alternator has the oem plug in it as well. The VR I purchased is a Toyota OEM, since I never had the OEM female I did use insulated blades temporarily to get it working. Then I got rid of the connector and soldiered the wires. At this moment it’s running/ charging but with some wires disconnected. The current readings are as follows:

At Idle
ALT READINGS
B terminal 13.80
F 13.50
N 6.97

VR READINGS
B 13.68
L zero “disconnected” (gnd on vr chasis supposedly for lamp but always on) closed circuit
F 13.20
IGN/condenser 13.60
N 6.94 (what is this terminal for?)
E disconnected 6.96

The ammeter gets up to 50 when I accelerate.

Such a simple and clean design yet a pain to me for now. I’m waiting on another oem unit to see if maybe this one is bunk.

Thank you again for your insight.
 

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