Stumped- 510 Battery Not Charging:Rebuilt Alternator, New Battery

[dougfj62]

I am stumped why the battery is not charging after some upgrades. Here are the details for a 1972 510 I have been slowly putting back together over the last year. 

1. Rebuilt 1990 Nissan Maxima 90 amp alternator 204-334B. had it retested after being rebuilt and is generating 14.2Volts(Sept 18th,2018)

2. Brand New Red Top Optima battery(Sept 17th, 2018 ) relocated  to the trunk. All wires and grounds checked, cleaned and tighten 

3. New Coil

4. New NGK plugs and wires

5. Rebuilt distributor - I set cylinder one to TDC and set engining timing. Car runs great as long as the battery is charged!

6. New Weber 32/36 carb installed

I do not use the key ignition to start the car. previous owner installed a push button start system. 

 

Battery voltage without starting the car is 12.6V. Start the car, no fuses are blown, the charge light has never come on, check the battery and the voltage reads 12.1V. If I check the voltage at the alternator with the car running , I still measure 12.1V.  If I turn on the lights they will last about 10mins before dying. If I drive the car a short distance the car starts lurching bc the battery is losing charge. This seems like a bad alternator to me. I have checked every wire from alternator and did not locate any bad wires. Is it possible that alternator is just not regulating the voltage correctly even though it checks out? The alternator was done by a shop specializing in rebuilding starters and alternators in north county San Diego. They have been great by checking the alternator and telling me there are no issues.  What other alternator can I install or try in place of the 1990Maxima 90amp alternator. Let me know what you all think this gremlin could be. 

 

[Draker]

Make sure there is power to the alternator via dash light wire otherwise the alternator will never turn on.

 

Classic case when bench testing yields good alternator, but in car is bad. 

[datzenmike]

The 510 uses an external voltage regulator. All Nissan alternators after '77 are internally regulated. You can't run an internally regulated alternator on a '77 or earlier Datsun and expect it to work. You can modify the wiring on the earlier Datsuns to work with them though. Basically it's unplugging and removing the regulator and joining two pairs of wires on the plug.

 

Join White/Black (stripe) together.

Join White/Yellow (stripe) together.

 

 

 I just made short jumpers and plugged into the regulator plug. Be sure to solder any wires twisted together and shrink wrap them.

 

[thisismatt]

Also, if the charge light is disconnected or blown (it should come on when the ignition is "on" but engine not running), then the alternator may not excite and will fail to output.

[thisismatt]

Similar to what mike posted, but with a little more information regarding the charge lamp wire & sense wire.

 

Edited September 19, 2018 by thisismatt

[dougfj62]

 

Thank you all for the advice/suggestions! Appreciate the feedback.

Just to clarify, the alternator was installed by previous owner, but I have not confirmed it is correct. I took multiple photos of the alternator before having rebuilt and installed as it was before. The car drove fine for months until this gremlin appeared.

This morning went to check the wiring  and went to start up the car.  the oil and charge lights now light up when I activate the electric fuel pump, which it was not doing before. I start the car and the charge light is now STAYING ON while the car is running. ???

This might sound like a stupid question , but if the charge light is on then there is power to it. Right?

Should I unravel the electrical tape to determine if the connections are correct as depicted in the above graphics? 

Thanks

Doug

 

Alternator/ Plug unit Pic

White/Red connected to voltage to battery

Black Ground attached to alternator and to fender ground.

Green/Green  from Plug (sending unit ) was connected to ground and now connected to voltage to battery

Yellow to Red  from Plug is not connected to anything.

 

Alternator/ To Starter Pic

White plug to red plug from alternator +

Yellow is the push start button

Red is a relay for electric fan on radiator.

 

 

 

 

 

 

 

 

 

[thisismatt]

This is a view of the alternator recepticle , so wire the plug this way:

 

 

At the alternator, the terminal left of the "T" goes to a switched +12v source off the ignition "ON" position. The terminal to the right of the "T" goes to your charge light. The charge light gets +12v from the battery on one lead and is grounded by the alternator on the other side when the alternator isn't excited. When the alternator excites and begins charging then it applies 12 volts to the other side of the bulb so you have zero potential across the bulb making the light go out. Sometimes there is a slight potential difference and you'll get a little bit of glow from the bulb.  This is all assuming the external regulator has been properly bypassed as in the diagram above.

[dougfj62]

 

@thisismatt , @Draker and @datzenmike

 

I am week behind had to drop our daughter off at college this weekend.

 

Appreciate the information and I do get it now. Makes complete sense. I have no problem with wiring and willing to dive into the deep end. I want to make sure I do this right the first time so I don't screw it up.

 

I want to either jump wires after the external regulator plug or straight into the the connector plug. I can wire the alternator plug with connectors that will plug into the external voltage regulator plug, white and white/Red.

 

Do I even need to keep the plug connected into the external voltage regulator since I am not using the ignition to start the car (push Button)?  

I did start the car without it plugged in and started  instantly. 

 

I just want to confirm with you all I have this correct in my head. 

 

1. The green wire (sensing wire) from the alternator plug will wire into the white/red

2. The yellow wire ( 12V ignition ON) from alternator plug will wire into the white

 

Again thanks to all helping me out with this. 

 

 

[thisismatt]

Easiest thing is to cut the plug & pigtail off the regulator and do the splicing there, keeping all the stock wiring intact and not having to introduce more wires outside the loom.  This is from my 521, but essentially the same:

 

[banzai510(hainz)]

for testing dont cut the wires off the regulator.

just make to jumpers wires with male blade ends and stick them in the engine side of the connector(the female connector). like a loop to the corisponding colors

 

If this was running before I dont get how this was working unless the external and the external was fighting each other but still enough charge to keep it running.

 

get a plug in Volt meter that goes in the cig lighter socket. they work great and dont drain the battery so you have instanct voltage cheack.

 

recheck the ignition fuse. I had a bad alternator that with pop the fuse for a split second then no charge. but if you ignition light is On then its more than likely fuse is OK

Edited September 24, 2018 by banzai510(hainz)

[dougfj62]

Shout out to the Ratsun Community!!! 

Rewired as shown in the posted diagrams to a 1990 Nissan Maxima internal regulated alternator.  Connected wires with solder, shrink wrap and tape for vibration/rubbing. Have oil and charge light when ignition is on  and when car is started light goes out as it should. While running the battery shows steady 13.7V at the battery.  Issue has been solve with simple rewiring. 

 

 

 

[Draker]

Nice work man!!