SteveJ

Jim, You can always download a copy of the 78 280Z FSM or any 280ZX FSM from XenonS30 or XenonS130. From there, you can see the alternator diagnostics. Another way to check is to take a voltage measurement at the battery with the car off. It should be between 12 & 13 volts with a good battery. Have a buddy start the car and hold the throttle to between 2000 & 2500 RPM. Take another voltage reading. It should be between 14 & 15 volts. To be perfectly clear, jumper out the external regulator BEFORE doing this test. This test is just off the top of my head, but the FSM will give you solid diagnostics. As for the voltage for the temperature sensor, detach the wire from the sensor, and measure from the wire to ground. The key should be in the ON/RUN position. The engine does not have to be running, but it won't hurt if it is running. The key position is what is important. You have to have voltage going through the gauge. By the way, has the oil pressure gauge been working? Those gauges have a common 12VDC+ coming in.

Darn, I thought I responded to this last night. If Enrique is correct that you have an internally regulated alternator paired with an external voltage regulator, then you should be able to detect that with a voltmeter at the battery with the car running. Unfortunately it's easy to detect because you'll have an overvoltage situation that can do VERY bad things to your electrical system. Also note that jumpering out the voltage regulator won't necessarily resolve the issue with the car not shutting off. You will need a diode in the alternator circuit when you use an internally regulated alternator to prevent it from feeding back through the ignition. For the temperature gauge, the sensor itself is the load in the circuit. You should be able to read voltage between the sensor wire and ground when wire is unplugged. It's good to verify that you have a signal first.

You could also try a brass hammer.

E, I misread part of his post. I thought he said he cleaned the sockets. Part of the problem is that the wire is on the small side for the current load going through it. IMHO the fuse should be 10A instead of 20A. That would better protect the wire. Yes, corrosion will make current draw worse since the corrosion can create a short circuit when it becomes so extensive that it breeches the gap between the positive contact and ground. However, from his description he chose to implement unique engineering solutions into a car where a previous owner apparently went to town already on the wiring. I would agree that the best way to test the system would be to take current reading on all branches, provided the wiring hasn't been hacked to a point where there are unknown parallel branches causing the overload. Most people (and I'm sorry if I offend Ron by including him in this group) don't know much about current measurements. It doesn't seem like he followed my earlier diagnostics that would have required the use of an Ohmmeter to track down his short. Having been victimized by the parking light circuit in both of my cars, I decided that the best course of action for myself would be to clean the sockets and substitute LED bulbs. I mentioned the parking light relay harness because it will give Ron the time to diagnose further without burning up his fusebox. Unfortuntately it sounds like he is close to burning it up already.

That is not an usual circuit to have problems. Go to Motorsport Auto and order the parking light relay kit. It was designed and built by Dave Irwin, aka Zs-ondabrain on this website. To see why parallel circuits would increase the current through the fuse, look at this example.

Download the FSM and fuel injection bible from xenons30. Follow the diagnostics on the fuel system. It sounds like you already have an idea that you are starved for fuel.

Which fuse is heating up? It could be caused by the addition of parallel branches on the circuit or a short created by corrosion.

Ron, Take a look at the BE (Body Electrical) section in the factory service manual (FSM). That will show you what you want to know.

If your fuel gauge is working then it is not the fuse. The oil, temperature and fuel gauges all go through the ACCESSORY fuse. Have you tested the gauges with a 9 volt battery to see if they work? Have you tested for voltage with a voltmeter at the connector for the gauge? See BE-2 in the FSM. You will need to have the ammeter/fuel gauge plugged in and the key in the ON position to verify.

You can also make your own. Vintage Connections has the right connector available. That's the way to go if you want to work on crimping skills. Otherwise, your PM to Dave should work just fine.

You would probably get better information posting in this forum. In the meantime, download a copy of the FSM from xenons130.com and use that as your reference.

(I think I might have posted this story before, but it does fit this thread nicely.) I hadn't spent much time working on my 260Z until this year. As I was replacing the speedometer cable, I noticed a wire running through the grommet. Since I knew this wasn't stock, I decided to investigate further. I traced it in the engine bay to the positive side of the coil. Okay, so the IPO (idiot previous owner) was looking to power something when the ignition was on. I then looked in the passenger compartment to see where the wire went. I followed it around the driver's seat and into the back. The years had taken their toll on this poor wire. Some insulation was missing, and the remaining was so brittle that it would snap like a dry twig. I finally found the wire poorly connected to the fuel pump. I'm not sure how it managed not to short out the ignition circuit. My guess is that the IPO who did that (at least 3 others have owned the car) tried to figure out why the fuel pump didn't get any voltage when he checked the circuit with the key in the on position. Eventually, I hope to get the wiring put back pretty much to stock.

Replacing the gauge isn't that difficult. Repairing it is much more of a challenge. I suggest removing the glove box for access to the backs of the gauges. Plus it gives you a way to slide them out. You can get a quartz movement put in your clock. See ZClocks for more info. Z Car Source, a site sponsor, does sell refurbished gauges. A member here sent his tach to Bob's Gauges. You could contact that website to see if he will refurbish a fuel gauge.

To elaborate on the solution from Steve, you could use a standard automotive relay to interrupt the fuel pump circuit. After opening up the yellow wire, one end would to pin 30 on the relay, and the other end would go to pin 87. You would need to use a switched source, such as the circuit for the radio and put the ends on pins 85 & 86. The circuit would be completed when the ignition is in the run position. There is a downside to this solution. In the event of an accident, the coil could still be energized. If you have an electric fuel pump, it would still have power. The original circuit (external voltage regulator) is energized only when the alternator is providing power. Some people have utilized an oil pressure switch as a fallback. Modern cars also employ a shock sensitive switch to cut the fuel pump.

Consider it a freebie. Searches build character. You may also find out information on something else that you'll need to know later.

Find the wiring diagram. You'll find it in the BE section of the supplement manual posted at XenonS30. It should indicate any inline fuses. The switch can be tested for continuity at the different on positions. Are you sure you got the wiper motor for the 71?

Here is the thread. The key for me was finding that there is another 6-pin connector between the wiring harness and voltage regulator. It's been a few years, but I think it's not too far from the plug for the voltage regulator. I unplugged it and put the jumpers in that plug. My battery stopped draining after that.

Yes. Search on here. There is a long thread on the subject. I haven't analyzed the 73 wiring as much as I should on this subject to give a blow-by-blow. For the 74 260Z, I have. In the 260Z, the fuel pump relay is wired between the alternator and voltage regulator. I suspect the 73 is wired in a simlar manner. Dave Irwin (Zs-ondabrain) might be able to confirm. I've attached a simplified schematic of the 260Z fuel pump wiring. When you jumpered out the voltage regulator, you energized the coil. While it's a relatively low draw, it's there.

The primary focus of this board is the S30 body style: 240Z, 260Z & 280Z. There is also support for the 240K and even some support for the 280ZX. You won't find much on the 300ZX in either the Z31 or Z32 body style.

A few years back, Wal280Z posted this thread. It has a pretty nice copy of the wiring diagram in TIF format. The Green/Yellow is listed as the parking brake switch. One of the black wires may go to the ashtray light, but the source is a Green/White wire. There is a Black/Red bullet connector and Black bullet connector going to the radio. You weren't specific on where the wires were located.

Actually, it's been about 11 years now since I lived in North Texas. I was out in Wichita Falls, so it was kind of a pain to make it to events, etc. I will say that getting to experience Mad Mike makes the dues for ZCot worth it. I also got to meet Bill Reagan before he moved out of the area. In some ways, the clubs don't change too much. I never tried to contact Cowtown because I don't even think I knew about them. That was in the days of dial-up internet anyway, so researching clubs wasn't as easy. Anyway, IMHO the club experience is what you make of it. Lord knows I've tried to recruit about any S30 owner I've met online or in person to join the Georgia Z Club. My long-term goal is to make the club more appealing to about any Z owner of any age. (I was inspired by talking to one of the members of the Cuban Mafia at ZCon )

Sure, just go to the site store...Oh yeah, it's gone. Contact Mike. He will provide details.

You didn't, by chance, buy the car from someone named James Burgess, did you?

While you'll find lots of newer Z's with ZCoT, I'm sure there are still plenty of people with S30s in the club. Heck, there were always a few at the Dallas Autorama, and Courtesy Nissan still gives support to the first generation. (How many Nissan dealerships do you know of that have sections of their parts websites dedicated to S30s?). Anyway, go to some club meetings, and talk to the members. See what cars show up, too. You could be pleasantly surprised. If not, contact the Cowtown Z Club and see if they have the atmosphere you're looking for.

Rockauto also offers a rebuild service with A-1 Cardone.