SteveJ

You may want to check out Vintage Dashes or search for Hung Vu on Facebook. https://www.classiczcars.com/forums/topic/67730-reproduction-240-dash/#comment-643729

It's not exactly plug and play. I just don't like cutting factory wires if I don't have to. One could back out the BW wires out of C-2 and C-3 and put them into smaller AMP connectors. The dash harness side would go to the key source on the Pertronix. The BW on the engine harness side would go to the BW on the Pertronix. That would save running a wire all of the way from the Pertronix in the passenger footwell to the coil.

D'oh, Mouser doesn't expect to get any of the 172508-1 until mid December.

If I'm correct, these are the same style connectors as C-2 and C-3, though photos of those taken apart would be helpful to confirm.

I'm thinking this is right, but I'm open to critiques. This is how I would see it going for the wiring. You would need to make sure you lift the wire between the ballast resistor and coil positive. Could this be done without running a single wire out to the coil? sure, but that would require more wire modifications between the dash harness and engine harness. Edit: Yes, it could be done without running the wire out to the coil, but it would require buying 2 sets of connectors to make jumper harnesses between C-2 and C-3 to intercept the BW wire at those junctions.

Agreed. I'm going to write up my suggestions.

Looking at the wiring diagrams: For the 280Z, I would think the grey wire would connect to the blue wire that goes back to the TIU and tach.

A friend of mine has been running the FAST system for a while. He has driven his Z to California and back at least a couple of times with it.

Found it Here are wires going to the intermittent relay: Obviously, the wiring diagram in the FSM isn't quite right for the intermittent relay as it shows 9 wires. There isn't a BY wire going to the relay, and there is only one ground wire.

Perfect. Now I can look for it in my car.

It is an interesting mystery. The wiring diagram was probably done well after the parts were designed, so it's not surprising. Humans were involved, and they didn't have the neat CAD software available to fix their mistakes quickly. Just today I noticed an anomaly in the wiring diagram for the intermittent relay in the 73. I would need to hook up my oscilloscope to see if the transfer is truly bumpless between start and on for the IG terminal on the switch. I don't think it is, but with the inertia of the engine once it fires, it could handle the very short gap in time.

So for #7, the LR wire coming off the fuse box goes in several directions. It turns into BY and goes out to the washer It goes to the Intermittent Relay for the wipers as LR It turns into R and goes out to the reverse switch (and inhibitor switch on the automatic). There is another LR wire that goes from the defroster switch to the defroster relay. I think there is a mistake on the wiring diagram for the intermittent relay. It shows the LR wire from the fuse box turning into BY when it gets to the intermittent relay, and another LR wire on the intermittent relay that goes to the wiper motor as BY. My guess is that BY and LR are swapped on the intermittent relay. Can you post a photo of #7 with a little more context in the wire bundle? That may help narrow it down.

I'm not an expert, but it looks like an early pan.

This may help you with identification

I don't think there is a need to measure the voltage fluctuation. That is how those meters operate. I forgot to include an example. Here's a video I did of a fuel gauge operating. You can see the current fluctuating on the power supply. That is from the gauge operating.

The fluctuation of the test light is right in line with the operation of the oil pressure metering circuit. If you measured voltage to ground where you put the test light, you would see fluctuating voltage. It would be easier for you to read the ohmmeter at the 200 ohm setting, but it appears as though the sender is working. It was disconnected from the wire from the gauge, wasn't it?

Thanks for the verification. At 15.7, the charging system is running high. Is that how it has been running, or have you changed out the alternator or voltage regulator? By the way, did you ever check the sending unit for resistance?

I'm thinking that if you replaced the electrical component, the replacement may have design changes from the original. Unfortunately it's a part that sees a lot of use over the lifespan of the car, so finding a completely original switch on an early car could be a challenge. This really doesn't go to solve Duffy's issue. It's really just to validate the wiring drawings, so I should make a separate thread for this rabbit hole.

Even if it just drops the air temp in the cabin to the mid 80s, that would be a BIG improvement for me.

If you spend too much time on this board, like I do, you learn things like that. I try to absorb as much as possible from the smart people here.

As designed by Nissan, the BW wire from the ignition switch is not the primary source for power to the coil while cranking. The GW (or GL depending upon the drawing) wire is. The reason is that the GW gives a hotter spark while starting, but in normal operation, the BW wire runs through the ballast resistor to drop the voltage to reduce the wear on the points.

I don't disagree with you except to say it's not a small point. I would say it's a moderately sized point. It would be great if someone with an earlier car could confirm how the "single screw" switch operates electrically. It's pretty easy, as I mentioned before. Take the BY off the solenoid, switch the turn signal switch to left or right, and put the key in start. If the turn signals flash, the BW wire is powered during start. @jfa.series1 Does your car have an original switch?

That's not a lot of weight if you live in the Southeastern US. You should have seen me after driving to Memphis and back for ZCON 2015. I would not have minded and extra 70 lbs at all for that trip.

Was 15.7 measured with a multimeter or read from the gauge in the car? This is why I like those cigarette lighter voltmeters. They are usually pretty close to a multimeter, and you can see the voltmeter and tachometer at the same time.

I remember seeing the post of the ignition switch wiring diagrams through the years. It's easy enough to verify on my 73. I just have to lift the solenoid wire off and have the turn signals on. If I have turn signals blinking while starting, then it has power while cranking. The 70 FSM indicates it is not powered during start. The wiring diagram in the 71 supplement shows the same, and the 71 Body and Chassis Part 2 PDF matches. The parts manual also indicates there were separate designs originally. I still have a new D8700-E4629 (in Beck Arnley packaging) that according to Courtesy Parts's website "Replaces: 48700-E4600, 48700-E4625, 48700-E4629" I did a continuity test on that switch and here are the results: (Red indicates continuity with the WR wire, and black indicates no continuity.) OFF Acc On Start So the BW is hot on that switch in start. Either D8700-E4629 is not faithful to the original design or the wiring diagram is wrong. Either way, I took the video Private until I can confirm so I don't muddy the waters with it.