Battery not charging with new 60A internal regulator alternator

[beermanpete]

The alternator output does not go directly to the ammeter. The whole car, minus the battery, is connected to the alternator output. The ammeter is in series with the battery, minus the starter.

Your comment that the ammeter does not move when turning on a load ( headlights, etc.) BUT the load operates might be telling. Is this while the engine is running or stopped?

The smoke that occurred and then stopped could be due to the smoking component burning out. Considering your comments, the ammeter comes to mind.

There is only one fusible link in the early cars. If you can start the engine, operate the lights, horn, etc. then the link is ok.

[Zed Head]

He said that the ammeter does move when he turns on the light.  Doesn't the alternator output run through the shunt?  Maybe the shunt is shorted.  I don't even know where the shunt is.

That wiring diagram I posted doesn't make sense to me.  It shows the output running to the fusebox (I assume that "A" is the output), and another fusible link in the battery cable.  I posted it because it shows a link, but the rest seems weird.

Whatever he does, he should check for shorts to ground before applying power or replacing fusible links.

[Zed Head]

Found an old post on shunts.  Follows beermanpete's suggestion about the ammeter.

SurferD said he bypassed the ammeter in Post #__ .  So, back to following the path from the alternator B/charge post to the loads.  Considering all of the facts I'm going to say he has a shorted alternator that smoked a link or the ammeter and he has been running off of battery power.  A guess.

 

Edited March 9, 2016 by Zed Head
Forgot the link about the shunt

[beermanpete]

I did misread SurferD's post regarding the ammeter working.

I have never seen a wiring diagram for the 70 Z. My comments are based on the 72-73 wiring diagrams. The basic arrangement is the same in the diagram posted above. The fusible link shown in the diagram above is not shown in the 72-73 wiring diagrams. The ammeter shunt is internal in the early models. 74 is the first year that uses an external shunt. This means all of the current into and out of the battery (except the starter motor) goes into the cabin and through the ammeter in the early models.

The alternator output feeds the fuse box via a white/red wire 10 gauge. This is the most likely circuit that would cause the symptoms reported.

[SurferD]

Wow suddenly there's lots of replies, thanks guys.

My car only has one FLink connected between the 10AWG white wire and the starter stud/+battery. I know it's good because I tested the resistance. My service manual schematic however says there's a FLink at the alternator RW wire which I don't see. The manual is from 1971 so it may be different from a late 1970 car.

As for the alternator, I connecetd the RW wire to the B (stamped on the case) terminal. I checked the case/terminal resistance and it's open which it's supposed to be. I have no idea why there was a soldered connection buried but as I have learned Nissan did some funny things with wiring at the factory. Maybe someone cut a wire on the line and they fixed it quick, or over the last 45 years something else happened and it was repaired by a tech. Either way it's fixed properly now. I connected the black harness wire to a E stud on the alternator. Then I plugged in the WB/Y connector to the mating socket in the alternator. I disconnected the ext. regulator and added the MSA diode connector. I described this in my first post.

I'll clear up the ammeter operation. When the car is not running and I apply a load such as lights, it drops slightly, while the engine is running it flutters a little and then drops a little when a load is applied. According to the schematic the RW alternator wire goes to the fuse panel then to the ammeter. The white wire goes from the ammeter to the starter/FLink and to the fuse panel.

While driving last fall with the new alternator I started seeing a little smoke and smelled burning. It only lasted a few minutes and stopped. I couldn't get it to repeat. It seemed to come out right in front of the speedo cluster but with stuff like that you can never tell exactly where. I pulled the dash out and couldn't find any evidence of burning or residual smell. I think now it was my ammeter. From what I've read guys bypass it or put in a voltmeter.

Yesterday I removed the console finisher (stupid heater control cables!), took out the ammeter/fuel gage and connected the RW and W wires that were attached to the ammeter and have yet to measure anything. It was getting late. If my thinking is correct I should have continuity between the +battery/starter stud/FLink and B alternator terminal if the ammeter was shot.

[Zed Head]

2 hours ago, SurferD said:

Then I plugged in the WB/Y connector to the mating socket in the alternator. I disconnected the ext. regulator and added the MSA diode connector.

You said that you fixed the solder connection, but then said that you still have open circuit on that wire.  You can't charge anything if the wire is not connected.

In the first post you said that you saw 17 volts across B to ground.  That means the alternator is charging but the S wire has no voltage to regulate to.  I think that S is the yellow wire at the T connection.  Supported by ...:

The fact that it charges implies that the other wire at the T, the L (looks like it says Light in the diagram) wire has voltage.

I would check the voltage at the T plug with the key on also.  You should have battery voltage at each wire, but it looks like one of them might be open (the S wire).  Also check your fuses at the fuse box.  If the white wire goes to the fuse box first, maybe there's a fuse on the charging circuit.  I don't now the 240Z, the wiring scheme they used seems a bit odd to me (but I have a 280Z so I'm biased).  But you have to get continuity from the B post to the battery positive somehow.

[SurferD]

Update, I was looking over the old regulator connector and found that someone had repaired the female spade connector on the white harness wire, which according to the shematic is tied to the large white charging wire. I took it out and crimped on a new one and installed it in the housing. I started the car and checked voltage across terminal B and the white charging wire and it now reads 5-6v as opposed to 0 before. I now have 18v from B to ground. I still have an open between W/FLink and WR terminal B when not running. I think maybe the small white wire has something to do with the no charge problem. Apparently it wasn't the ammeter.

I checked the T connector WB/Y for 12v with the key on. Yellow has 12v White /black stripe does not. The WB is the wire that goes to the diode in the MSA adapter plug.

I also ruled out a fuse failure. I have the upgraded MSA circuit board style and while engine was running I pulled each fuse sequentially and the car remained running.

 

Edited March 9, 2016 by SurferD

[Zed Head]

Seems like you're making some progress.  Still a little difficult to figure out exactly where you're measuring.  The white wire should be attached to terminal B and should have zero voltage on it since they are in effect, the same wire.  So the 5 voltage drop implies that there is current flowing and high resistance, IF you're measuring at the other end of the wire. Where exactly is the probe on the white charge wire?

The 18 volts is an overcharge, which shouldn't happen if the S terminal is connected in the right place.  If it's connected at the end of the 5 volt drop though that might explain the over-charging.  The alt. should hold voltage to about 14 max. on the S terminal.  Could be that the internal regulator is fired in your alternator.  Maybe have it tested.

In theory the alternator shouldn't charge without power on the W/B wire.  There's no current for the windings.  So that doesn't make sense.  Apparently, some alternators will have enough residual magnetism in the cores of the windings to charge, if the engine is revved up.  I'm not really clear how that works, but that's often how "one-wire" alternators are set up.  Also not clear why you don't have power there.  Check the T plug to be sure you don't have a stray wire hsorting across S and L at the connector when you plug it in.

You have some very odd numbers.  Since the car apparently ran before for a while, it seems like things must have been right then.  Maybe the MSA plug doesn't work on the very early 240Z's.  You might consider removing it, identifying the S wire and the L wire using your meter, and inserting your own jumpers in to the regulator plug.  You can even run a separate wire directly from the battery for S, just as a test.  All you really need is the L wire.  You could even just run one wire to to both from the battery.

You might even be able to run a separate, thick, wire directly to the battery positive for charging.  The circuit might be backward, and the engine will probably keep running when you turn off the key but you can at least get some hope that things might work eventually.

The 5 volts drop on the charging wire, the lack of power on the W/B, and the 18 volts charging with nowhere to go, are all weird.  Weird weird stuff here.

[SurferD]

I found a helpful site with a diagram of where the wires should go and what they do.

http://woodworkerb.com/home/datsun-240z-rebuild/datsun-240z-alternator-upgrade/

[Zed Head]

I've seen that, it's a good clear description.  Your problem is that you have no power on W/B, and your charging wire (white with red, W/R) doesn't seem to be connected to anything, or is shorted.

I would disconnect everything and focus on getting battery power at yellow (S), power at W/B (L), and a good solid W/R wire path to the fuse box, as beermanpete described.  The W/R at the fusebox would enter the box from behind.  Get those three things right then worry about connecting them to the alternator.

[SurferD]

Well I looked it over again and since the only thing introduced to the system other than the alternator is the MSA plug with diode I pulled it and did a continuity check. The white/yellow connection was good but the wb/bw connection which is the switched 12v was open. I dug out the potting and the diode had a broken lead. I took the spades out and put them in the harness connector with a jumper and made another jumper for the W/Y. After starting the car I had 12.5v across the battery. B terminal to ground was 14-15v. Voltage to ground at the large white wire/FLink at the starter is still only 2.5 when I think it should be 14.

So I think that was the culprit 

[Zed Head]

Good detective work.  Is that from MSA, the plug?  Dave Irwin, Zsondabrain,  might want to hear about that.

Be careful with what you have right now.  If the thick white charging wire isn't carrying the current to the loads, like the battery and the fusebox, then any smaller wires tapped in to it might.  That's how wires end up like grannyknot's pciture.  You might be seeing low voltage at the battery because there's a lot of resistance on the way there.  Might not hurt to just run a 10 gauge wire from B to the fuse box, like the diagrams show.  Make sure that proper path is there.