Help On 3G Page

[85lebaront2]

That Alternator, with the right angle stud adapter looks exactly like the one on my Taurus did.

[Machspeed]

85lebaront2 wrote

That Alternator, with the right angle stud adapter looks exactly like the one on my Taurus did.

Bill, that alternator is for a 93 Ford Taurus....LOL!  

[ArdWrknTrk]

And, in a Taurus you'll see why the adapter is better than a right angle lug on the charge cable.

[85lebaront2]

Just because on the 3.8L it sits almost against the upper plenum shouldn't be a problem, GM would put it on straight as long as there were a few thousandths of space.

[Gary Lewis]

Ok folks, I need you to review something for me.  PLEASE!

But, before I 'splain what it is let me 'splain my cunning plan.  I'm going to present these ways to do it: with a warning light or with a voltmeter monitoring either battery voltage or ignition switch voltage.  That is because there seems to be enough interest in using the LG/R wire from the ignition switch rather than installing a relay.

And speaking of the LG/R wire, the relay will be pulled in by it rather than stator voltage.  That's because it seems easier to wire it up that way since you can use the LG/R wire both to pull the relay in as well as to provide power to the voltmeter.  (Besides, it was easy to draw it that way, as you'll see.  )

So, what I need you to do is to go to the page at Documentation/Electrical/3G Conversion/3G Conversion - In Development.  Then drill down on the Wiring It tab, then the Ammeter Tab, then the 2G tab.  There you'll find these two tabs:

Monitoring At The Ignition Switch: This one isn't done as it doesn't have the "here's what your wiring looks like & where you should cut" schematic nor the "here's your harness and where you should cut" picture.  But it has the final wiring schematic.  And if you agree with the next tab I can finish this tab.

Monitoring At The Battery: I believe this tab is done.  And, I think it is what John/Machspeed is looking for.  But, I need feedback from y'all.

And, disregard the tab that says Disregard This Tab.  I need to delete it but that isn't the easiest thing to do so will wait to see that you agree with the approach of moving the stuff about the voltmeter into the Wiring It tab.

[Machspeed]

Morning Gary! So where is the 4 gauge wire that comes off the alternator and goes to the other side of the mega fuse in your drawing? I see that wire in red on the battery side of the mega fuse, but not on the alternator side. I think I brought this up once before.  

[Gary Lewis]

Morning, John.  And a COLD morning 'tis.  Showing -3F here and still snowing.  Have maybe 4", although that is very hard to tell with the blowing, and supposed to get another 2 - 4" before it quits today.  And then we are to get another 4 - 8" tomorrow night!

Anyway, good catch on the wire from the alternator to the megafuse.  And, I was planning on wrapping the Y/W wire back to the alternator's output.  Plus take the color off the alternator's output wire as not everyone will have a BK/O wire.

Thanks, I'll work on those things in a bit.  Anything else?

[ArdWrknTrk]

Be mindful, Gary that...
A) for those of us with idiot lights, that filament has to support both the exciter current and the relay pull-in....
B) you can't sink that wire through the relay, because the light will stay on.
C) if for some reason the alternator failed, the light would still be on because the relay is sinking it.

You know, I wonder sometimes....

[85lebaront2]

Good point Jim, Darth, with the 1996 dash has both and idiot light with a battery symbol and a voltmeter. If you look at the diagram, there is a "fail safe" resistor in parallel with the light, so even with a burned out bulb the LG/R wire will still be powered with the key on.

[ArdWrknTrk]

But is a 512 ohm resistor enough to pull in a relay and power the alternator?

If there is another ground path, will the light ever go out, as it does when the alternator starts charging and both sides of the filament come to the same potential? (Because they won't if there is a path to ground through the relay pull in)

[Gary Lewis]

Guys - On the version with a warning light there won't be a relay.  Just the light, with its resistor in parallel, going right to the alternator to bootstrap it in.  That's the easy peasy one - that I haven't tackled yet.

So, what am I missing?

[ArdWrknTrk]

Where's the voltmeter you want connected with a relay, to XYZ point of the charging system (cab/battery?)

[Gary Lewis]

In a Bullnose, up through 1985, you get either a warning light or an ammeter.  Not both.  We are converting the ammeter to a voltmeter so need a relay.  But with a warning light there is no voltmeter so no need for a relay.  Just use the wire from the light to bootstrap the alternator in, like was done on the 1G.

[JimsRebel]

Gary Lewis wrote

And speaking of the LG/R wire, the relay will be pulled in by it rather than stator voltage.  That's because it seems easier to wire it up that way since you can use the LG/R wire both to pull the relay in as well as to provide power to the voltmeter.  
Snip....

If you use the LG/R wire to power the volt meter you do not need a relay.
The voltmeter would only get power with the Key ON.

It is my understanding that you added a relay, when the voltmeter was reading "always HOT power" near the battery, to eliminate the parasitic battery drain ( .068 amps).

Using a relay with a idiot light would cause a constant current flow through the light bulb filament, and a series circuit. You should test this on the bench with a relay - light combination. Or maybe the ALT would source the needed current for the relay. This is not something I would not recommend, at least at this point, to many unknowns.

Regarding the 2G harness photo, showing the cut points:
Keep in mind you will have to replace the voltage regulator plug with a NEW plug that has all 3 wires.

Jim #2

[Gary Lewis]

Jim - In reverse order:

When you say "you will have to replace the voltage regulator plug with a NEW plug that has all 3 wires" do you mean a new 3G plug?  

As I said above, I don't see a need for a relay when there's a warning light.  There is no voltmeter and we added the relay for the voltmeter.

And you are exactly right, the relay is to eliminate the constant drain of the voltmeter when the engine is off.

As for the LG/R, you are right that you can use it to power the voltmeter w/o a relay.  Which is why I've shown it that way on the Monitoring At The Ignition Switch tab under 2G.  (I want to get the 2G tab done before moving on to the 1G tab.)

[ArdWrknTrk]

My 2G had a three wire regulator plug.
Maybe some didn't???

[JimsRebel]

I did see the drawing, and yes it was correct, but the text earlier stated the relay would be used with the LG/R wire.
 

Quote... My 2G had a three wire regulator plug.
Maybe some didn't???

The drawing used here only has 2 wires. My truck only had 2 wires. It might just be a 1986 only issue, I don't know.

On a 1986, with a 2G ALT, if it fails and you pick up a replacement 2G at the auto parts store, it will NOT work if you only have 2 wires on your wire regulator plug. You will have to replace the plug with a 3 wire plug to get it to work.

Replacement voltage regulator plugs are sold as 2G - 4G.
If you had a 3 wire 2G voltage regulator plug, it would fit (and work fine) into the 3G ALT as is.

Jim #2



 

[ArdWrknTrk]

Yep, mine did.
But maybe that's something that changed with Bricknose?

I can't say.
I only know what I encountered.

[Gary Lewis]

Ok, I think I see what is being said about the 2G regulator plug.  But we addressed the needed 3G harness on the tab at Wiring It/3G Harness.  So we've effectively said you need a new regulator plug.

However, your point is that if you have a 2G regulator plug with 3 wires you can use it on a 3G.  Right?  If so, I could say that in the discussion about the regulator plug.

As for the relay being used with the LG/R wire, it is - in the situation where you want to monitor battery voltage.  Here's the way I understand how we are using that wire:

Warning Light: LG/R wire goes directly to I terminal on the regulator

Voltmeter Reading Ignition Switch Voltage: LG/R wire goes both to the I terminal as well as to the positive side of the voltmeter

Voltmeter Reading Battery Voltage: LG/R wire goes to both the I terminal as well as is used to pull in the relay.  But, note that the way I had the relay wired was W.R.O.N.G!  I've corrected it now, but previously I was setting the voltmeter up to read the difference between the battery voltage and the ignition switch voltage.  

Anyway, I've now changed the wires to red and wrapped the sense wire, the one going to the A terminal on the regulator, back to the alternator's output, as we've discussed.  And, fixed the error in the relay wiring.

With that I believe the 2G wiring when monitoring at the battery is both correct and done.  Please check it out.

[Machspeed]

I'll let the two Jim's respond. We need an "eating popcorn" emoji, cause that about all I'm doing on this ride.