Alternator Upgrade Issue

[dutchzcarguy]

On 10/10/2022 at 7:15 PM, eastcoastz said:

I purchased a 60A 280ZX alternator

Just ask myself why you wanted to "upgrade"?  As the wiring is NOT made for a higher amperage it's also a firehazard...

To people that need more amps i would suggest to make all the lighting LED and save a lot of power for example for your boombox? 🙂 

ALso...  The wires in a 240z are now 50 years old and already have a big task to transport the already to big amps in these cars.. so again.. it's a bad idea to even try to put more current through these old wires.  (I'm astonished no one said this here before!.. ( for as far i read this topic hey...hihi...))  It's a accident waiting to happen..  

[eastcoastz]

That makes totally sense about the old wiring... I've added a few additional electrical components (Petronix Ignitor II, aftermarket radio, NISMO fuel pump, etc.) and I read that the 60A alternator was a common upgrade that seemed easy enough to try.  I still need to find some time to test the wires for voltage as recommended, so I'll write back on this thread soon with the results.

[SteveJ]

11 minutes ago, dutchzcarguy said:

Just ask myself why you wanted to "upgrade"?  As the wiring is NOT made for a higher amperage it's also a firehazard...

To people that need more amps i would suggest to make all the lighting LED and save a lot of power for example for your boombox? 🙂 

ALso...  The wires in a 240z are now 50 years old and already have a big task to transport the already to big amps in these cars.. so again.. it's a bad idea to even try to put more current through these old wires.  (I'm astonished no one said this here before!.. ( for as far i read this topic hey...hihi...))  It's a accident waiting to happen..  

Unless the owner has added a big stereo, the alternator won't necessarily be putting out more current than the old alternator. On the other hand the excitation curve is improved over the old alternator, so it is putting out enough at lower engine RPMs. (I know this has been mentioned in the past over at ZCar.com. I don't know if it was mentioned here.) This can make a difference with blinkers functioning properly, headlight illumination, etc. Granted, LEDs can also help with lighting performance, and I am a big proponent for them. 

I have used a ZX alternator in my 240Z for over 20 years without problems, and I put a Frontier alternator (70A) in my 260Z last year. It's not an accident waiting to happen.

 

[Zed Head]

Wires are affected by current and current results from the draw of the devices at the ends of the wires.  The alternator is a pusher.

Your battery has all of the energy necessary to smoke all of your wires in to dust, except the giant battery cables, which would probably cause the battery to melt down before they withered away.  It would be a contest.  Even the cheapest battery has 675 cold cranking amps (CCA) available.  They're the same amps that an alternator puts out.  Take a small piece of wire and touch the ends to the positive and negative terminals of your battery at the same time for a demonstration.  Wear gloves or use pliers.  Post a video.  Seriously, it will be a neat demo.  The battery is just sitting there waiting to destroy your wires.

https://www.oreillyauto.com/detail/c/economy/battery---accessories/batteries/31624da3221a/super-start-economy-battery-group-size-26/ssbd/26ecoj/v/a/16439/automotive-car-1971-nissan-240z?pos=9

Edited October 12, 2022 by Zed Head
Why is "postive" not flagged as a misspelling?

[eastcoastz]

... so the initial impression is that the new alternator is not draining as fast as the first "new" one.  I still need to test the voltage on the battery a little later again.

 

One odd thing that I've noticed with this second new one is that sometimes at idle, the ammeter (in the car) goes a crazy/wonky... the needle moves around side to side from like middle of the left to middle of the right (like a seismic needle... haha).  If I give it a little gas while it's doing this, the needle goes back to center and stays there.  Has anyone else seen this before?

[SteveJ]

The test I suggested still applies. If you see voltage on the black/white wire with the key off, that's your problem. If there isn't voltage on the black/white wire, then it's on to testing with an ammeter, but I'll supply those directions if necessary.

As for the ammeter gauge dancing, it means that the alternator is cutting its output. Make sure you have enough tension in the belt. What is your idle speed set to on the car? What is the voltage to ground at the yellow wire on the T connector at the alternator? The last thing I can think of is a possible issue with the voltage regulator in the alternator.

[eastcoastz]

@SteveJ  Thanks so much for your help... I really appreciate it!  I apologize for the delay in getting back to you.  I just had a chance to run through the tests and here are the results:

• Black/white wire has no voltage when the key is off
• Yellow wire on the T connector has 13.27 volts with the key off
• Yellow wire on the T connector dances around between 14.8 - 15.1 volts when the car is on (idling)

I no longer appear to have the issue with the battery draining while sitting, but I do still/now have this issue with the ammeter dancing.  When idling the ammeter needle sweeps the entire gauge over and over. 

Once I rev up to about 2500 rpm, the needle dancing settles down a little but still occurs.  I also noticed that the E-Brake light (in the speedometer) is pulsating when idling.

Does this sound to you like I have yet another bad (new) alternator?

[Zed Head]

Maybe your jumper wires are tied to a flasher circuit somehow.

I would take another look at the wires you used the jumpers on.  Use a meter and find the one that is always hot.  Connect it to S.  Find one that is only hot with the key on, connect it to the L terminal.  Don't try to use jumpers at the plug, just run a new wire to the alternator terminals.

[eastcoastz]

When I say that the E-Brake light is pulsating... a better word for it, would be that it is slightly flickering when the ammeter needle is dancing.  It's not pulsating to the point that it is on a standard repetition like a blinker/flasher.

Nor is the needle dancing with any repetition... it just goes all crazy when idling and gets a little better when the engine is revved up.  I also forgot to mention that I currently have it idling at about 900-950 rpm.

[Dave WM]

On 10/14/2022 at 4:22 PM, eastcoastz said:

... so the initial impression is that the new alternator is not draining as fast as the first "new" one.  I still need to test the voltage on the battery a little later again.

 

One odd thing that I've noticed with this second new one is that sometimes at idle, the ammeter (in the car) goes a crazy/wonky... the needle moves around side to side from like middle of the left to middle of the right (like a seismic needle... haha).  If I give it a little gas while it's doing this, the needle goes back to center and stays there.  Has anyone else seen this before?

Yes but it did it on mine regardless of engine speed. Also when it went to the charge side my headights got much brighter. It always started with a few seconds of high discharge, like 30-40 amps out of no where for a second or two then would jump back to 30-50 amps charge and much higher than normal voltage (again head lights) I was concerned that if not for the load of the battery, the voltage would have skyrocketed even more. At 1st I assumed it was a VR issue (i had the external VR) however a swap to a known good did not correct the issue. I replaced the alternator and have not had an issue since. Now the swings I mentioned were for full seconds not fractions, enough to make you think someething bad was about to happen. I have always gotten momentary spikes bot those were indeed momentary. Not sure what is causing them, but does not seem to hurt as I have put a lot of miles on the car with no electrical issues since the fix.

[eastcoastz]

Thank you @Dave WM  Yeah my ammeter is going crazy non-stop when the RPMs are below 2500.  Here a video of what mine is doing:
 

https://youtube.com/shorts/YmhfYndqG4E?feature=share

 

I talked with Remy/BBB (the supplier/refurbisher of these alternators)... described the issue to them and they said it sounds like a bad internal voltage regulator.  Since this is the second bad unit from them, the guy I talked to said he is filing a QA report to his team. 

 

Can it potentially damage the wiring/electrical in the car if I continue to drive it like this (until the third (new) alternator arrives)?

[Zed Head]

3 hours ago, eastcoastz said:

• Yellow wire on the T connector has 13.27 volts with the key off
• Yellow wire on the T connector dances around between 14.8 - 15.1 volts when the car is on (idling)

Actually these numbers do look like a bad regulator, IF you are back-probing the S (yellow) wire. 

But, If the yellow wire is the wire to S and you're unplugging it to take a measurement then you are removing the Sense wire to the regulator. 

Anyway 15.1 volts is too high for a ZX internally regulated alternator.