Help Identifying Alternator

[HuD 91gt]

http://www.classiczcars.com/topic/46888-240z-alternator-upgrade-instructions-w-pictures/

 

 

I used the diagram in this thread as it seems to be one of the few which talk about the 240z directly.  I do have a "P", so it should be regulated.  I'll head out shortly and test the voltage as well at the top of the T.

 

 

I also just noticed I may have done something incorrectly in regards to that diagram.  I left connections 3 + 4 on the left diagram (To regulator), not connected.  This is correct, no?   In fact, I never used the regulator side connector at all.  I just used 4 spade connecters and put them directly into the female side of the connector (alternator side) and taped it all up.   Leaving the connections which would be 3 + 4 empty.

Edited June 7, 2015 by HuD 91gt

[HuD 91gt]

Also to note, the alternator that was on the car looked identical to the 1975 you posted, but the external regulator was still being used..  Is this correct?

[HuD 91gt]

The T, has a a high resistance on the vertical portion. The top of the T, I get no reading at all.

The top of the T also shows battery voltage when the connection is in place.

[Zed Head]

The T, has a a high resistance on the vertical portion. The top of the T, I get no reading at all.

The top of the T also shows battery voltage when the connection is in place.

 

Not sure what you mean when you say "connection in place".  The diagram in your link is meant for the voltage regulator to be unplugged and the connector cut off of it.  Then those wires are connected, with the diode, and it's plugged back in to the car harness.  It reroutes power back into the harness to the new places it needs to go.

 

You can do what you described, but you would unplug the VR completely, then run jumpers from 1 - 2, and 6 - diode-5 on the harness connector.  I'm not sure which side is male and which female, but the connections have to be on the side that goes back in to the harness. 

 

Easy to get those plugs backwards in your brain.  Your measurements show that something's wrong.  You should battery voltage top and bottom of the T with the key On, for sure.  The top is for regulation and the bottom energizes the winding.  And I think on the top of the T with the key Off ( not positive on that one). Measure at the alternator T plug, with it disconnected.

[HuD 91gt]

I just got back home from the garage, and after running a small ground straight from a bolt on the alternator to the body I've think all my resistance readings were a bit off.   My voltmeter was acting funny, I have a feeling the battery is probably close to dead.  I'll get a new battery and check it over when I get back from work on Monday.  It's too bad, I would have liked to have driven the Z, I get satisfaction driving it to work the odd day.

After running the ground, I started the car and there was no change.  There is also a capacitor (or resistor) that was mounted to the old VR which was somehow wired into the old harness. I left it there when I did the install (pictured).  When the car was running, I disconnected the capacitor and immediately the voltmeter show a much more "normal" charge of 10-15amps, but the needle still flickered quite a bit.  I didn't rev the engine too much as it's getting late and the car is in a residential neighbourhood.  Does anyone know what this capacitor did on the old setup?  Do I need it now?  The write-ups I see don't mention it at all.

 

 

So, in the photo below, (sorry I couldn't find an app on my mac to highlight the areas on the photo) the VR connector is taped up.  I used spade connectors, and followed the diagram from the link posted.  I then used electrical tape to make it weatherproof.  The capacitor is also in this photo, and it is more central, screwed into where the VR use to be mounted.  When this was disconnected from the system, the reading was much more "realistic", but the needle was still erratic.

 

The photo below is just a photo of the VR connector taped up.  Not really anything to see here.

 

 

This is the back of the alternator. I ran a ground (blue ring terminal) from a random bolt on the back.

[HuD 91gt]

Not sure what you mean when you say "connection in place".  The diagram in your link is meant for the voltage regulator to be unplugged and the connector cut off of it.  Then those wires are connected, with the diode, and it's plugged back in to the car harness.  It reroutes power back into the harness to the new places it needs to go.  

 

Sorry, by connection in place. I meant that the wiring harness was connected to the alternator.  I was receiving battery voltage from the one connection which the ignition off.  I will check again with the ignition on when I get back next week.

 

You can do what you described, but you would unplug the VR completely, then run jumpers from 1 - 2, and 6 - diode-5 on the harness connector.  I'm not sure which side is male and which female, but the connections have to be on the side that goes back in to the harness. 

 

This was done.  I made very sure I had the connections correct. I checked multiple times.  We can be assured this is correct.

 

Easy to get those plugs backwards in your brain.  Your measurements show that something's wrong.  You should battery voltage top and bottom of the T with the key On, for sure.  The top is for regulation and the bottom energizes the winding.  And I think on the top of the T with the key Off ( not positive on that one). Measure at the alternator T plug, with it disconnected.

 

With the plug disconnected, I will check the harness side, and expect 12v on both connections with the ignition on, and only one with it off?  Do I have this correct?   When I checked with the ignition off only one showed battery voltage.  No reading on the other one.

Edited June 7, 2015 by HuD 91gt

[Zed Head]

 

 

With the plug disconnected, I will check the harness side, and expect 12v on both connections with the ignition on, and only one with it off?  Do I have this correct?   When I checked with the ignition off only one showed battery voltage.  No reading on the other one.

I'm not sure which plug you're talking about.  Probably just me, not grasping the words.  Once you do this modification the "plug" is essentially gone.  Many people cut the plug completely off of the car's wiring harness to connect those wires.  The only "plug" that is left is the "T" plug at the alternator.

 

It's also possible that some other part has been modified in your car that used to carry the top wire of the T plug.  That is the main problem with those write-ups, there are assumptions that everything else is still stock.  For example, on my 76 that wire also powered a relay, that would stay on and drain my battery.  I had to do more work and ended up just running my own "S" wire.

 

So what you could do (and other people have done this also) is to run a separate wire from the top of the T to the battery.  That should do the job for sensing voltage.  You could also just check continuity from the top of the T plug to the wires at your new splice.  One of them should be the S wire.  I think that atlanitcz site has a better diagram to show what's what.

 

 

Forgot to say - I've also run male blades connectors in to the back of plugs to make a connection and found that sometimes they just won't stay metal-to-metal.  It feels like it's working but it just isn't.

Edited June 7, 2015 by Zed Head

[HuD 91gt]

I'm not sure which plug you're talking about.  Probably just me, not grasping the words.  Once you do this modification the "plug" is essentially gone.  Many people cut the plug completely off of the car's wiring harness to connect those wires.  The only "plug" that is left is the "T" plug at the alternator.

 

I actually meant the T plug.  English/literature were never my strong courses

 

It's also possible that some other part has been modified in your car that used to carry the top wire of the T plug.  That is the main problem with those write-ups, there are assumptions that everything else is still stock.  For example, on my 76 that wire also powered a relay, that would stay on and drain my battery.  I had to do more work and ended up just running my own "S" wire.

 

So what you could do (and other people have done this also) is to run a separate wire from the top of the T to the battery.  That should do the job for sensing voltage.  You could also just check continuity from the top of the T plug to the wires at your new splice.  One of them should be the S wire.  I think that atlanitcz site has a better diagram to show what's what.

 

With the ignition on, I ended up getting voltage from both connections.  Strangely enough, only one was receiving 10.5volts (ignitor sourced one), the other 12V (battery)

 

Forgot to say - I've also run male blades connectors in to the back of plugs to make a connection and found that sometimes they just won't stay metal-to-metal.  It feels like it's working but it just isn't.

 

I took apart my blade connections, and cut up the VR side of the connector to use.   Soldered it all together, and started the car.   The alternator wasn't putting out anything and operated at a sub 12 volts.  This actually happened the other day for the first ten minutes after starting, then the erratic needle and high current charge started happening and I completely forgot about the lack of anything at the beginning. I let the car run, and drove it around a little and the alternator still didn't kick in.  Hooped alternator?  Regulator?

I ended up splicing the VR connector back to the VR, and installed the old alternator.  I guess I'll have to check this alternator more thoroughly and maybe get it tested....  or just get a new one?  All in all a couple days wasted, and now a ugly spliced connector ha.  But the car works, and thats whats important since I needed it tomorrow to head to my fabricator to get him to measure up the rear for a hitch.

Thanks for your help guys.

Edited June 9, 2015 by HuD 91gt