Low alternator charge at idle

[Crackedback]

You need to measure voltage, not resistance.. And it should be done with everything connected & the engine running..

The picture shows how to back probe a connector... I use sewing needles.... They are using a fancy tool that they sell... My way is the old cheap way..

View attachment 1758411

Do you have a thimble or two around. Your quilting club must be pissed with the missing needles!

Awesome working hack using the sewing needles. Well done

 

[1 Wild R/T]

Do you have a thimble or two around. Your quilting club must be pissed with the missing needles!

Awesome working hack using the sewing needles. Well done

Back when I was working in the trade lots of guys would use pins & needles... Many would go straight to puncturing the wires insulation... I always tried to back probe connectors but if that failed I would poke the insulation... Ya gotta get your test results to diagnose stuff somehow...

 

[Kern Dog]

I read "resistance" in post # 94 and took it literally.

 

[1 Wild R/T]

I read "resistance" in post # 94 and took it literally.

Thing is that blue wire going to the regulator is the reference voltage the the regulator needs to know when to force the alternator to charge... So if the wire has high resistance and the voltage going to the regulator is 2 volts low the alternator will charge 2 volts high....

The test should be looking for voltage drop... The reason for voltage drop is resistance... You could ohm the wire but the ohm meter may not push enough amperage through the wire to reveal a problem....

 

[Kern Dog]

SUCCESS !

The adjustable voltage regulator arrived the other day along with the pigtail.

Maybe they include the pigtail to allow owners of the 1969 and earlier cars the ease of installation?
The box had no instructions inside, just what you see here.

Instructions were not necessary though. It has a slotted button on the back.

Hard to screw that up, right?

Before all of this, the other alternator and regulator had the car idling at around 14 volts with no lights or heater-A/C fan going. With those on, the volts dropped to 10-11. That is what motivated me to make changes.
The Tuff Stuff alternator and regulator helped a lot but went too far. I was at 15+ volts. I tried 2 other regulators and got the same reading. The wiring was good, everything is well grounded so I figured that this regulator would fix the issue.

Fast idle but that is where it likes to be.

The volts are where they need to be now too. At first, it was charging at 15 volts! I turned the button CCW and it went up to 16. Turning it clockwise brought it down to a slightly wavering 13.8 to 14.0. With the headlights on at idle, it drops to 13. A/C and lights drops only a little more. This will have to do. I tested at the terminals on the battery that is in the trunk.
I’d rather err on the side of caution rather than cook the battery and have to spring for another one.
Score !

 

[70ChargerRT]

SUCCESS !

The adjustable voltage regulator arrived the other day along with the pigtail.

View attachment 1760410

Maybe they include the pigtail to allow owners of the 1969 and earlier cars the ease of installation?
The box had no instructions inside, just what you see here.

View attachment 1760411

View attachment 1760412

View attachment 1760413

Instructions were not necessary though. It has a slotted button on the back.

View attachment 1760414

View attachment 1760415

View attachment 1760416

Hard to screw that up, right?

Before all of this, the other alternator and regulator had the car idling at around 14 volts with no lights or heater-A/C fan going. With those on, the volts dropped to 10-11. That is what motivated me to make changes.
The Tuff Stuff alternator and regulator helped a lot but went too far. I was at 15+ volts. I tried 2 other regulators and got the same reading. The wiring was good, everything is well grounded so I figured that this regulator would fix the issue.
View attachment 1760418

Fast idle but that is where it likes to be.

View attachment 1760417

The volts are where they need to be now too. At first, it was charging at 15 volts! I turned the button CCW and it went up to 16. Turning it clockwise brought it down to a slightly wavering 13.8 to 14.0. With the headlights on at idle, it drops to 13. A/C and lights drops only a little more. This will have to do. I tested at the terminals on the battery that is in the trunk.
I’d rather err on the side of caution rather than cook the battery and have to spring for another one.
Score !

I’m glad it worked out for you.

 

[__Larsson____]

Go Denso or go home. Much cheaper option. And yes, you can install it with factory brackets by adding two 5/8" spacers. And they are internally regulated so you can gut or ditch the regulator on the firewall. Installing one requires the addition of ONE additional wire direct from the alt to bat +. You will need to do some research on which ones have a double pully.

Running, it will hold 14v with accessories running. Below, installed on my 69 GTX 440...
View attachment 1730034View attachment 1730035View attachment 1730036

So you do not need to connect the 3-pin connector to anything?

 

[Sinitro]

SUCCESS !

The adjustable voltage regulator arrived the other day along with the pigtail.

View attachment 1760410

Maybe they include the pigtail to allow owners of the 1969 and earlier cars the ease of installation?
The box had no instructions inside, just what you see here.

View attachment 1760411

View attachment 1760412

View attachment 1760413

Instructions were not necessary though. It has a slotted button on the back.

View attachment 1760414

View attachment 1760415

View attachment 1760416

Hard to screw that up, right?

Before all of this, the other alternator and regulator had the car idling at around 14 volts with no lights or heater-A/C fan going. With those on, the volts dropped to 10-11. That is what motivated me to make changes.
The Tuff Stuff alternator and regulator helped a lot but went too far. I was at 15+ volts. I tried 2 other regulators and got the same reading. The wiring was good, everything is well grounded so I figured that this regulator would fix the issue.
View attachment 1760418

Fast idle but that is where it likes to be.

View attachment 1760417

The volts are where they need to be now too. At first, it was charging at 15 volts! I turned the button CCW and it went up to 16. Turning it clockwise brought it down to a slightly wavering 13.8 to 14.0. With the headlights on at idle, it drops to 13. A/C and lights drops only a little more. This will have to do. I tested at the terminals on the battery that is in the trunk.
I’d rather err on the side of caution rather than cook the battery and have to spring for another one.
Score !

Very kool but..
Why did they place the adjustment screw only accessible
when the regulator is unmounted and not grounded??
If it was accessible from the front, then any tweak adjustment could be easily done.
And they could have covered
the adjustment screw with a snap-on cap..

Just my $0.02...

 

[Kern Dog]

I agree. Maybe the goal was to make it look closer to stock?

 

[1 Wild R/T]

So you do not need to connect the 3-pin connector to anything?

Yes the three wires need to be connected... Well, two... One goes to switched power (IE the original blue wire to the alternator) One goes to a 12v reference point, (isolated wire from the battery) the third wire is for an idiot light...

 

[__Larsson____]

isolated wire from the battery)

Yes the three wires need to be connected... Well, two... One goes to switched power (IE the original blue wire to the alternator) One goes to a 12v reference point, (isolated wire from the battery) the third wire is for an idiot light...

So im from Sweden and just to be clear, (12v reference point,) means constant 12v with a fuse?

 

[threewood]

So im from Sweden and just to be clear, (12v reference point,) means constant 12v with a fuse?

No fuse. It is a wire direct from battery to alternator. It gives the alternator a constant look at battery voltage so it can regulate properly if I understand it correctly.

 

[1 Wild R/T]

No fuse. It is a wire direct from battery to alternator. It gives the alternator a constant look at battery voltage so it can regulate properly if I understand it correctly.

It can and should be fused... But it should be a dedicated feed with no other loads that could effect what the alternator is reading...

Lots of guys just feed it from the main power wire coming out of the alternator but that doesn't allow the alternator to see what the battery actually sees...

 

[threewood]

It can and should be fused... But it should be a dedicated feed with no other loads that could effect what the alternator is reading...

Lots of guys just feed it from the main power wire coming out of the alternator but that doesn't allow the alternator to see what the battery actually sees...

Makes sense. Fuse shouldn't affect the reading. Mine is not fused BTW. Going on 4 years with the Denso alt and it has been perfect.

 

[__Larsson____]

Okey! Nice

It can and should be fused... But it should be a dedicated feed with no other loads that could effect what the alternator is reading...

Lots of guys just feed it from the main power wire coming out of the alternator but that doesn't allow the alternator to see what the battery actually sees...

Okey nice! So one +12v switch. One to the +Bat and one lamp if i want it Many thanks to you and to Threewood

 

[1 Wild R/T]

Okey! Nice

Okey nice! So one +12v switch. One to the +Bat and one lamp if i want it Many thanks to you and to Threewood

Of course it wants to load sideways..
S = 12v from battery
IG = 12v switched
L = idiot light

 

[Bird 426]

I have or had a similar problem with my Dart. Charge then no charge soon after leaving the house. Tried 2 new voltage regulators, well, it was the rebuilt alt. I know, but I am not good at electronics. So then the system was charging 14.8 after warm up. I got one of the adjustable voltage regulators. It was 14.9 out of the box. Now, after adjusting it's 13.8 at idle and 14.2 at high rpm.