280z starts but has a massive parasitic draw

[CN280z]

I have a 280z that sat for 5 years. I got the car up and running a few weeks ago. I failed an emissions test (am planning on getting classic car insurance which by passes emission test requirements in AZ) (idk if that has anything to do with my issue but figured I’d mention it.)

the car was running fine and I didn’t notice any issue. I had to turn the key a few times to get the car to start but it stayed running. I drove it around, got an oil change at big o tires. When it came back and after a few new body parts and paint (which I had to remove my tail lights for, but reinstalled from what I can tell correctly) the car now won’t stay on. As I drive the car around the amps drop to under 8 and the car dies. Once dead I have to jump start it to get it back running and shortly after the same issue will occur. It constantly does this. Now it’s to the point that when I jump the car and turn it off it’s instantly dead again.

i assumed maybe this was an alternator issue. I changed the alternator today and I’m experiencing the same issue. When jumped the car sits at 13v removing the cables it lowers to 12v then slowly drains till it chokes out. Sometimes quickly sometimes 10-15 mins later. I have a video of the issue with starting the car, it acts like there is no power then instantly starts after 4-5 turns of the key. (It doesn’t crank when it turns then fires right up.)

I checked all of the fuses I could find on the interior fuse panel and they are all good and removing them doesn’t change my parasitic draw. Which is registering 9-11v if I’m reading that correctly. (I am not an amazing mechanic by any means and am figuring this out as I go)

my fusible links look good…I am just at a loss and don’t even know where to start. I have searched forum after forum and all over the internet and the closest issue I found was someone talking about their MAF but mine seems to be running just fine, when I remove the harness the car chokes out and dies like it should.

 
i just spent close to 3k on body parts to fix the car up. and now I can’t drive it. Which is a total pain. Hope someone might have an idea on the next step. 
 

the battery was purchased in the last 2 weeks and the alternator purchased yesterday

here is the video of what I’m experiencing please ask questions to get me thinking about more. Remember also my knowledge base is limited haha

280z has 36k original miles, motor, tranny and majority of original parts 

[SteveJ]

What year 280Z?

[CN280z]

1975 non Cali model 

[kickstand80]

Sounds like your alternator is not charging. So either you have a bad power circuit to/from the alternator or the alternator you purchased is bad. 

You have an external voltage regulator that could be causing the alternator to not do its job.

Check to see of the parts place you purchased the alternator has the ability to test the alternator. If its good then I would suspect the voltage regulator. Dont forget that this is a 50 year old car and any if not all of the electrical connections can be suspect or corroded. Get the FSM and go thru the testing: Free download here:

http://www.xenonzcar.com/s30/fsm.html

[SteveJ]

Charging problems with two alternators first points to the voltage regulator, especially since you didn't say whether or not you changed it. Keep in mind that if the voltage regulator is original, it is adjustable. The EE section of the FSM has the procedure. In addition to the link @kickstand80provided, you can download the FSM from here: 

The EE section is available, but unfortunately some other sections are not. (This applies to either download site.)

If the voltage regulator is not an OEM part, it's probably time to replace it. You should test the alternator first, as was suggested. It looks like MSA has the best price for a VR, https://www.thezstore.com/page/TZS/PROD/12-4083. You may want to bite the bullet and order it today so it ships before they are closed for the long weekend.

[Patcon]

I would also caution against using a new alternator to charge an exceptionally dead battery. Thats a good way to destroy an alternator

[Zed Head]

7 hours ago, kickstand80 said:

Get the FSM and go thru the testing: Free download here:

http://www.xenonzcar.com/s30/fsm.html

No need to go to Xenon when this forum has the same files.

https://www.classiczcars.com/files/category/13-280z/

Seconding the bad VR possibility.  It's probably not a "parasitic" draw.  It's a normal draw, with no recharging.

And, the ammeter should sit at zero when everything is off.  It will go negative when the system is discharging and positive when it's charging.  The EFI and ignition system will draw current while the engine is running.   If you turn off the key and it sits on the negative side then you really do have a draw.  

[Racer X]

Why replace the alternator without testing the charging system, the starting system, and load test the battery?

Simply guessing and throwing parts at a car is the worst way to go about troubleshooting.

Test, prove what is malfunctioning, repair, then test again.

 

That said, follow the testing procedures in the service manual. Find the problem and correct it. Most auto parts stores can test the alternator and the battery, to either confirm they are serviceable or not. Testing the voltage regulator should be covered in the service manual, and can be done with a voltmeter.

[Zed Head]

8 hours ago, CN280z said:

here is the video of what I’m experiencing please ask questions to get me thinking about more.

That video didn't download.  Most people create a Youtube channel and upload their videos to it.  Makes them easier to view.

Sounds like a nice project especially if it really only has 36,000 miles.

[CN280z]

Hope this helps with the fact that the video won’t download  <——- click to see issues with starting the 280z

 

also I uploaded some pictures of the regulator. It looks decent but there is some black melted goop that has hardened. Dunno if anyone knows what that is.

[Zed Head]

The Youtube "short" only shows you starting the engine.  Not much info in it.

In your first post you were talking about volts but as I noted you should have an ammeter in your car, if it's a 1975.  Are you sure it's not a 76?  The build date can be in 75 for a 76 model.  The voltmeter came in 1976.

Do you have a hand held meter?  Volts and resistance?  If not you should get one.  There are good options available for about $30.  You need it if you're going to diagnose electrical problems.  

Here's an ammeter and a voltmeter.  Not sure what you're working with.

[CN280z]

4 hours ago, Zed Head said:

The Youtube "short" only shows you starting the engine.  Not much info in it.

In your first post you were talking about volts but as I noted you should have an ammeter in your car, if it's a 1975.  Are you sure it's not a 76?  The build date can be in 75 for a 76 model.  The voltmeter came in 1976.

Do you have a hand held meter?  Volts and resistance?  If not you should get one.  There are good options available for about $30.  You need it if you're going to diagnose electrical problems.  

Here's an ammeter and a voltmeter.  Not sure what you're working with.

I used a volt meter hand held to give y’all the volts rather than the amps. I have an amp meter in the car.

 

i showed starting the car because the draw that I am having started when the problem started with me starting the car. 
 

that video was while the car was being jump started and fully at 13.9v plenty enough to start the car but I have to jiggle the keys 3-5 times to get it to actually even attempt to turn over.

 

im assuming the events are correlated. I’ve been told starter, ignition switch, voltage regulator. Possibly bad battery/alternator. Just trying to give as much info to help narrow it down.  I know it doesn’t showcase the volt draw or anything like that hoping it shows someone something though lol. I down right hate electrical and it doesn’t quite make sense to me:(.