NewZed

You thought half-right. http://www.nicoclub.com/FSM/280z/

I just took a second look at your picture and see that the PCV hoses are gone. There's your problem. Put the PCV system back together. Google "280Z PCV vacuum leak". Read the Emissions chapter. It's all there.

Could be you shorted an injector ground and are flooding. Check the plugs for fuel. Are you spraying the starting fluid in to an intake port or somewhere else like at the end of the plastic snorkel? Best to remove a hose and squirt directly in to the manifold. If you're getting spark, the timing is right, and the cylinders are dry, it should start. Odds are high though that you left a big vacuum leak when you removed those "vacuum lines" whatever they are. Why would you do that, they serve a purpose?

Why guess when you don't have to? All you need is a meter. Maybe even just a test light.

Are you figuring things out on your own or did you use the testing procedure in the Factory Service Manual? Page EF-54. The AFM switch is a common problem that can confuse people not familiar with how the system works. Those relays are hard to find but they've been seen on eBay. There are also a few places that sell replacements that work. http://www.zcarsource.com/fuel-injection-relay-280z-280zx-300zx_8_56767.html https://www.summitracing.com/parts/bck-203-0053

I think we're just wondering why the AFR's didn't raise a question. Should have shown as way lean if they were clogged. Your "tuner" wasn't tuning. He was just running a dyno.

Later ZX's use an O2 sensor also. Not sure what the ECU does if there's no signal at all.

They changed the pins at the ECU in 1979. Somewhere out there is an explicit instruction to never connect a ZX ECU to a Z harness, or vice-versa. You can use the compete EFI system on an earlier engine. But the harness alone won't transplant. Maybe the ECU plus harness, plus some modifications to the fuel pump control. But not a direct harness swap. Use the 1980 EFI Guide if you want to study the differences. http://www.xenonzcar.com/s130/other.php

How are you checking for spark? Maybe you left the rotor off? It happens.

Sorry, but you're not understanding the principles of electricity. The coil has continuity from the positive post to the negative post. They're connected. Therefore, when the positive post has voltage so will the negative post. If the points are open, they'll be exactly the same because no current is flowing. One side of your points should also have the same voltage. Measure battery voltage with the key off, then measure at both coil terminals and the points with the key on. Measure resistance to ground on the other point, the one with no voltage, to make sure you have a good ground. You can also measure resistance to ground of the capacitor/condenser. It should not have continuity. With the key off, measure resistance of your coil also, from the neg post to the pos. If all of the parts measure right, and you get them connected right, you should get spark. There's stuff on youtube that shows all of this. Points ignition systems are common to all brands of cars.

I think that you meant zero current when the points are open, not voltage. He'll have battery voltage when the points are open, and a voltage drop when the points are closed. Points are the switch to ground.

Pints work by opening and closing, breaking and making the circuit to ground for the coil. You can test the ignition system with your finger by closing and opening the points with the key on. If you set the gap when the points are supposed to be closed, they'll stay open and you'll never get a spark. Find a source on the internet that explains Kettering ignition systems. Your statement below doesn't make any sense. " I have used a ohm meter to check that the plug on the distributor is grounded and it is when the point is closed. "

Post the diameter of the round exhaust ports and I can compare to my squares (rectangles). To see if it's just somebody's fancy porting job. Although that won't explain the casting stub (sprue).

That is odd looking. My 76 N42 has the same type of font, little 4, big 2, but it doesn't have the casting port remnant, the square stub, next to it like yours. Could be a head from Asia, from one of the JDM-type suppliers. They didn't go to the emissions heads, with liners, for quite a while after the USA did, apparently. Tony D has posted on the general topic, I believe. Maybe it's a linerless head designed to use the round exhaust manifolds that the liner heads used. The liners probably add cost and complexity.

Sorry I can't be of more help, but if you haven't been in to how the EFI system works, you're starting from scratch. There are several things that can affect idle behavior. Testing is fairly simple but you need to understand how the parts work individually, and how the system works as a whole. It can take some study.

Test the air regulator. A cold engine needs a richer mixture than a warm engine. A vacuum leak makes the mixture lean.

The cold start valve only operates during Start. It squirts fuel only while you're trying to start the engine. Once the engine starts it's done. Running problems after the engine starts aren't likely caused by the CSV. For about a minute after starting, the air regulator (aka AAR) should be open to keep the idle speed up. Usually though, the engine is still cold when it shuts completely. You can test the AAR to see if it's opening and closing correctly. You might have a vacuum leak. They can cause a lean condition that is more significant at idle when cold than after warm up.

Show the plug side of the plug, not the wire side. And FSM means Factory Service Manual, you're not using Chilton or Haynes are you? Get Factory, Open Emissions chapter, go to BCDD section. I said "kind of" because you didn't show the telling part. That port is right next to the coil and distributor wire connection block. It's an odd one and looks like it should have a counter part connector. But it doesn't, unless Nissan has a machine that automatically tests. Maybe they do it during assembly.

And it's not connected to anything. It usually has a rubber cap.

Kind of looks like the test port for the BCDD. Check Emissions chapter. Also shown in the wiring diagram right across from the Air Flow Meter (AFM). These cars don't have a MAF sensor. The MAFS can be called an AFM, but not vice versa. The diagram shows more wires because they show all versions - California, Federal, Auto, Manual.

How did your "tuner" miss that?

Don't the MS logs show what spark and injectors are doing? You talk about falling off a cliff and crapping out but nothing about what the logs show. That's the beauty of data-logging, you don't have to guess at what happened, only what caused it to happen. Fun to review all of your specs. but the logs should tell you what's (not) happening. Spark and injector open duration.

The study was done by AMS. Kind of suspect, I'd say.

That noise sounds more like an alternator whine or maybe a vacuum leak in a hose. Kind of high frequency. Have you checked the air gap on the distributor reluctor? Might be rubbing. Have you checked fuel pressure, and the vacuum hose to the FPR for fuel? Sometimes the diaphragm leaks, making things rich, even though fuel pressure looks right. Pull the hose and see if it has fuel in it, or pull the hose and run the pump to see if it leaks.

Considering all, wouldn't he really be better off going with Megasquirt? The odds of getting something that runs well at the end seem better. Even if he gets all of the wires right, he's stuck with whatever "tune" has been flashed to the chip, which may or may not be right for that collection of parts. And it's not really a JWT chip or ECU if "ecutunerguy" flashed it, is it? It's an ecutunerguy setup. Probably shouldn't even be mentioning JWT.