FJ40 Voltage too high AND too low. lucky me

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Oct 17, 2021
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Albany, Oregon
My 71 FJ 40 has issues with the charging system. the system was checked and alternator voltage at idle was 0. After replacing the Alternator and regulator TWICE, problems continue. An alternator shop bench tested the alternator and it’s OK. The regulator is the commonly found cheap import with no labeling. Big picture, the voltage now jumps over 17 at high rpm. Also, the voltage at the fuse panel reads under 11 with the car off (perhaps confusing the regulator). See the chart below for measured voltages. I won’t be driving it with those high readings. Should I start with the regulator points calibration as detailed in other threads? Is the low voltage at the panel not significant? The regulator ground wire is good, but could the F wire be the problem? Thanks for looking
B816BDDD-9EB2-4C73-96C1-074AA15F6BCD.jpeg
 
Joined
Oct 17, 2021
Messages
7
Location
Albany, Oregon
My 71 FJ 40 has issues with the charging system. the system was checked and alternator voltage at idle was 0. After replacing the Alternator and regulator TWICE, problems continue. An alternator shop bench tested the alternator and it’s OK. The regulator is the commonly found cheap import with no labeling. Big picture, the voltage now jumps over 17 at high rpm. Also, the voltage at the fuse panel reads under 11 with the car off (perhaps confusing the regulator). See the chart below for measured voltages. I won’t be driving it with those high readings. Should I start with the regulator points calibration as detailed in other threads? Is the low voltage at the panel not significant? The regulator ground wire is good, but could the F wire be the problem? Thanks for looking
View attachment 2820392
Update: cleaned all grounds. Adjusted VR to specs. Still low voltage at idle. Ignition key unit tested and losing some ohms so ordered replacement. Also suspect electronic ignition is pulling down the overall running voltage and confusing VR. only 11 volts at fuse panel. Cannot see any fusible links off battery positive or behind instrument cluster. wondering if new electric power steering soaking up power even when not driving? Moved the thick white cable from N to B terminal on alternator As well.
 
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Western victoria Australia
my 3f alternator doesn't charge much at idle either. Drops under 12v with the lights on. The pulley diameter on these alts are pretty big.
The electric steering should be drawing almost zero when not being steered. Are you sure your volt meter is accurate? 17v seems really high.

Also the b+ terminal is the correct spot for the large charge cable. When it was on the N terminal it might have mucked up the regulation causing the 17v.
 
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Joined
Oct 17, 2021
Messages
7
Location
Albany, Oregon
my 3f alternator doesn't charge much at idle either. Drops under 12v with the lights on. The pulley diameter on these alts are pretty big.
The electric steering should be drawing almost zero when not being steered. Are you sure your volt meter is accurate? 17v seems really high.

Also the b+ terminal is the correct spot for the large charge cable. When it was on the N terminal it might have mucked up the regulation causing the 17v.
I agree the idle voltages with loads can be quite low albeit typical. I have it’s VR in the 14 volt range at 2000 rpm now after bending the armature. Was using a HFT meter until it imploded, and my new digital meter confirms what my Dakota dash gauge shows. Thanks for helping.
 
Joined
Oct 17, 2021
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Albany, Oregon
Do you have the 40 amp alternator? Perhaps it's a bit shy for your add-ons. Have you totaled up your amp draw?
It’s an Autozone reman about 55amps. Checking amp draw is a good idea. Here are the results of my recent tests. At 2000 rpm it does climb to 14.29 Volts. Cheers

3D33C387-E94F-4530-94EF-687E4B5F83F7.jpeg
 

Steamer

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I have no experience with electric steering but a quick Google tells me they draw quit a bit. Does your ammeter go into discharge when your voltage is below normal charge? (still gotta ammeter?) Maybe disconnecting the power steering for a test would shed some light.
 

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