SteveJ

High voltage is usually one of two things. The voltage regulator is failing. The battery sense voltage isn't present. Basically, pull off the connector for the voltage regulator. Measure voltage to ground on the white/red wire on the engine harness side of the connector. It should be battery voltage. That wire comes off the black fusible link, so likely it is the voltage regulator.

Brake fluid resistant o rings: https://satoriseal.com/epdm-o-rings/ Possible source: https://www.globaloring.com/product-category/o-rings-standard-sizes/epdm-o-rings-70-duro/ Also Grainger: https://www.grainger.com/category/hardware/o-rings-and-o-ring-kits/o-rings?attrs=O-Ring+Material|EPDM&filters=attrs&gucid=N:N:PS:Paid:GGL:CSM-2296:9JMEDM:20500731&gclid=Cj0KCQjwmvSoBhDOARIsAK6aV7hsgn4gz-ujED1fAZtebKNIUrXo8v9nFtvHkkFkzsinR_BlCy2wcGcaArBbEALw_wcB&gclsrc=aw.ds ebay: https://www.ebay.com/itm/191606666667?chn=ps&mkevt=1&mkcid=28&srsltid=AfmBOor_yVAmh3TJG4uEj6AhV9ox_DipN4S0kR0MRQJokpwBeTghkeCWF7A&com_cvv=d30042528f072ba8a22b19c81250437cd47a2f30330f0ed03551c4efdaf3409e Finally McMaster-Carr: https://www.mcmaster.com/products/o-rings/

I'm glad you found your answer. I looked a little online and through a couple of service manuals yesterday. I had some understanding of how it was supposed to work, but I think the drawing you just posted explains it better than I could have. Most of the drawings I found didn't show the heater strip clearly like that one does.

Actually 12.8 is an acceptable voltage.

The discussion of the fuel pump probably deserves its own thread, but I'll go ahead and give my 2¢. Measure the pressure in the fuel rail before you do anything else. It should not be more than 4 PSI. If you removed the mechanical pump, then you can measure pressure at the entrance of the fuel rail. Otherwise measure the pressure between the rail and one of the carburetors. There is no fuel pressure regulator. There is only an decreased orifice at the exit of the fuel rail. If your pump outputs more than about 7 PSI, you will have too much pressure in the fuel rail. (Note: Most of the PSI ratings for the small fuel pumps are exaggerated.) If you are buying a new pump, then electric is probably the way to go. I have seen too much online (and heard from amongst Z friends) about new mechanical pumps not performing. If you are determined to replace your electric fuel pump, consider a model like a Carter P4070 (https://www.amazon.com/Carter-P4070-Line-Electric-Fuel/dp/B000CIQ5DG). Keep in mind that any replacement fuel pump will require some routing of fuel lines. I also suggest considering a couple of lengths of Sidewinder fuel hose in the right diameter (https://www.amazon.com/16-Universal-Molded-Fuel-Line/dp/B07G2ZWGRG). This helps prevent kinking hoses. I used some on a friend's car, and it looked like it really belonged in the car. I like having an inertia switch in the fuel pump circuit, too. It can be one salvaged from a wrecked car or a new generic one from Amazon. They can cut the fuel in an accident even if the driver is incapacitated.

That certainly explains the ammeter reading. The reading in your latest photo seems to show the fuel pump draw if the battery was fully charged given how you say everything is wired. What is the voltage reading with the battery topped off and car running?

Good thinking. I tried finding a grommet, but all my grommets were too thick. I used a small slice of 1/2 inch heat shrink, and that held the bulb socket in place better.

Yeah, run a test with you holding the positive meter lead firmly on the battery post while the car is running and warmed up. If the voltage is below 13.5, reach across and operate the throttle slowly while looking at the meter. See if the voltage will hover more in the 14 volt range. Please trace out that red wire. I'm wondering whether someone "fixed" the wiring in the past or just added things.

I ordered a set, too. It takes a little pressure to push them through the hole, but it's not very snug. On the other hand, I think they may stay in place better than some other wedge socket swaps I have done in the past.

A loose connection could have caused issues. How and where were the meter leads connected to the electrical system in your video. The meter certainly was jumping around. You may want to test without video to see what the voltage is. I did see it popping up to a little over 14, so if it is staying in that range, that should be good. I'm wondering if the ammeter is off or if you really are pumping out as much current as it's reading. It's not a precision gauge, but that looked to be around 20A, maybe more. I would expect to see that if there are a lot of loads on the battery side of the ammeter (I'm still curious about that red wire.), or a battery that is going south or had been greatly discharged. You may want to put the battery on a charger for a few hours and pull the fuse on the red wire. Then see if the ammeter is still reading like that.

@SteveJ It's like going into Wisconsin. @Captain Obvious Well I got the $#!+ kicked out of me in Wisconsin once. Forget it!

Third day in a row taking the car out. Only 4 Zs showed up, including mine. That could be from ZNationals happening yesterday. Then there was this unique vehicle. I'm not used to taking car photos in portrait mode.

I was over there a while back, but I don't recall if I looked at them. @Yarb did you?

I have used wedge (194) sockets to replace bulb sockets in my 260Z. These aren't the ones I used, but I think they may do a good job of staying where you need them: https://www.amazon.com/uxcell-Wedge-Light-Instrument-Socket/dp/B00W8W5MR4

Today I was celebrating the birthday of a brother from a different mother. He also happens to be a Z enthusiast. Every car in that photo except for my 260Z and the 280Z between my car and the Roadster is his. Plus he still has the 240Z he bought from Redwing (Jai) in his garage waiting to be reassembled. Since it was his birthday, I got the horns and speedometer working in his Roadster. He swapped a 240Z for the Roadster. The Roadster has a 2.4L turbo engine in it. Unfortunately, the wiring looks like it was done by a body guy, and the body looks like it was done by an electrical guy. I've been helping him sort out electrical gremlins and install better connectors. He's done a lot of work on my 260Z in the past, so I'm just returning in-kind. A few other Zs showed up along with a 240SX and a G60. There was even a 65 Mustang 2+2 and a 1st gen Camaro SS on hand. There was one strange guy there who was saying something about needing to go to Czechoslovakia to rescue his platoon as he left.

Those are beautiful sounds.

Auto AC Solutions

Nostalgic AC is about an hour and a half from you in Ocala.

Great question, sir. What's happening at this point is that the bar on the diaphragm is not opening the contacts. Before you disassemble, connect your ohmmeter to the horn and tighten the volume screw slowly until the resistance goes up. Then back it down some. Test again and see if the bar can open the contacts.

I looked at the dimensions in front of the radiator. It looks like this condenser would probably work best: https://nostalgicac.com/parallel-flow-condensers/14-x-24-superflow-r-134a-condenser.html. Nostalgic AC doesn't offer those dimensions on a condenser with an integrated drier.

Are you referring to Nostalgic AC?

Here's how you should check the voltage. Make sure the 6 pin connector is plugged in. Unplug the connector from the alternator. Measure voltage to ground at the red wire and green wire. The red wire should have battery voltage. The green wire should not. If the first test passes, put the key in ON. Measure voltage to ground at both wires again. This time both should have battery voltage. The starter you linked was the one I was referring to. It's difficult to find parts not made in China. After you fix your starter and get ready to run your car again, make sure you measure the voltage while the car is running at the alternator and then check at the battery. I'm starting to think there are some problems lurking in your car that you may need to address. If the voltages are significantly different, that would confirm my suspicions.

Hanging out at Atlanta Motorsports Park north of Atlanta for ZNationals Track Day.

Well guess who has the Frontier alternator. Your alternator is connected properly, too. I just verified against my car. However, the crimped lug on the red wire is curious looking. If I can remember, I will make a video to show you how to verify the wiring. When you say that the wire burned through, are you taking about the wire between the solenoid and starter? If so, look on RockAuto for a 280ZX starter. They have some listed as new.

Here is the deal. As far as I'm concerned, there are gaps between the documentation and reality for the 75. On page EE-14, the manual shows a charge light. Since I've never owned or really worked on a 75, I can't tell if it exists. The 75 should still have an ammeter as far as I know. I don't have a full 75 FSM, so I don't have the BE section to cross-check anything. The parts manual shows an ammeter for the 75. So where would the charge light be? I don't know.