Zed Head

There is a "can" or cylinder inside the tank, which has the fuel pickup point inside. That's where the crud would be. There is a screen or "sock" at the end of the tube to block particles from passing in to the pump. If your tank has been sealed in the past it might be that some of the sealant has come free. A borescope might tell you something. You can find quite a few pictures around the internet of the inside of the tank but for some reason people rarely take a picture inside the can where the end of the tube is. It's strange. https://atlanticz.ca/zclub/techtips/fuel/gastank/index.htm

Yarb's suggestion is good. You could make it easier and leave the return line alone though and let the gas flow in to the tank, if you just want to test the pump and tank. If it was mine, I'd disconnect the inlet hose from the tank and stick it in to a can of fuel back by the pump and tank. Measure pressure once. You'll know. Super easy. Your symptoms kind of sound like the "crud in the tank" problem. The crud floats around in the tank and gets sucked on to the inlet pipe sock, clogging it. Then when the pump turns off it floats free. Break your problems in to pieces. And yes, page 79. The higher the resistance the more fuel the ECU adds. Corrosion on the connections can cause excess resistance.

You might be getting distracted with all of the different things you're looking at. You said that you were getting 36 psi. That is the correct pressure. Looks like your fuel supply and control system is working right and you were just running out of gas. If you're getting ~36 psi with the vaccum hose removed from the FPR, or engine off, and it drops to about 28 - 32 psi with the engine running then the FPR and pump are working fine. Move on to other things. I'd measure resistance on the water temperature sensor circuit at the ECU connector. The 1980 EFI book is the best resource for doing that type of work. Go to the electrical section.

Did you reproduce the original cover dimensions and just add fins to it? I've not really examined a diff cover, let alone an R180's. The one you show looks a lot different than your modified version in post #16. What happened? The factory covers have quite a bit of internal bracing. Here's a Subaru's.

I only see four products on their page. The video is titled LED Turn Signal Kit but it looks like it's about the backlit Z emblem on the quarter panel. I guess they tap into the turn signal circuit with their wiring harness branch and convert the emblem to a turn signal. $150 does seem steep for two bulbs, two sockets, some wire, some sheathing, and four plugs. But they did do the leg work to find the parts. They broke the plastic in the video, and you have to drill a hole. Seems like a lot to get a light in the emblem. Are you saying that you will modify the Amazon part for free and then reship it? Total cost would be the Amazon price plus Amazon shipping cost plus your shipping costs. I tried to figure out what Harmon charges for shipping but you have to put in too much info. https://harmonresto.com/

Seems like you're implying that your fuel filter was clogged. But in Post #36 you said you got 39 psi. ??? I assume that gauge was between the filter and the fuel rail. Might be that you had a vacuum leak at an injector or two and you fixed them when you removed and replaced the injectors. Wahtever it was, good luck with it. On to the next problem...

Does pressure drop immediately when the pump is not running? If pressure drops it might be the FPR. It could have foreign matter holding it open. You can clamp the return line closed with some vise-grips and test pressure again. If it shoots up above 36 then it's not the pump or the supply side. Be careful if you can't see the gauge while you turn the key. A typical aftermarket pump will hit 90 psi. Also, the pump should not be loud. That's a sign that it's working hard to pull fuel in. Could be a clogged pickup tube in the tank. Gather more clues.

Your firing order is correct. One possible reason for no change might be that the timing is very retarded. You need to get a timing light and see where it is. You'll also be able to see if it's changing when you move the distributor.

That's the PCV valve, not the BCDD. Yes, the PCV hose from the block to the PV is a specially formed hose. Yarb referred to it above. Small one end, big on the other. When things aren't tuned well the engine will often be non-responsive to tuning efforts. Kind of a vicious cycle, a rabbit hole. The missing and break up at higher PRM are probably due to the massive vacccum leak through the PCV valve under the intake manifold and also through the hole in the block. Air can enter the crankcase through the hole in the side of the block and travel through the engine to the intake manifold. You can either block the two PCV holes, or get the proper hoses connected. The EFI system will not work correctly with a partially intact system. .

A 200 vehicle "encrustation"? Where is it now? It's real.

Cosmoline? Protective coating for over water shipping.

Examples -

Take some measurements. Measure the opening of the rim. Maybe it's not meant for a Nissan. Measure the stud lengths. Use the method I described and be sure that the studs are pulled all the way in. Besides the problems you've had there's a lot more wrong with what you're doing. Those hubs are flithy. The area where the rim contacts the hub should be clean, on both the hub and the rim. No offense intended, but there are more people than you and your wife/girl friend at risk here. Get some help from somebody who knows cars. People get killed by wheels that fall off of vehicles at speed. Not the ones in the three-wheeled car, the people that get hit by the 50 mph wheel. Besides the guilt, you'd be financially liable. Sorry to be a downer, but there's quite a bit wrong in this thread.

It's the hose connected to part # 7, the PCV valve, in the drawing on Page EC-2. The Emissions chapter. I'd post a picture but the function is broke. It's underneath the intake manifold.

That's the thread I was thinking of but I couldn't find it. Unless the comments are in the one I linked. My general impression has been that the vapor lock problems caused people to make changes. And swapping to round tops from flat tops was a common change. Going back to what was known. Kind of like removing "emmissions junk", or going back to carbs from EFI. The past always seems more comfortable.

It might be in this thread somehwere.

I think that there's a long discussion on the forum somewhere about switching to round tops, and when it often happens. Not sure. I'm definitely not a carb guy. The text says that they were rebuilt. "Service in 2023 is said to have included rebuilding the carburetors, replacing the ignition switch and spark plug wires, flushing the fuel and cooling systems, and performing a valve adjustment and an oil change."

Another 73 is up for sale, but with very low miles. Looks garage kept. I wonder if the hoses, hydraulics, booster, and other parts will hold up long if somebody starts driving it again. An odd dilemma - keep the original parts but don't drive it, or replace the parts and enjoy it. https://bringatrailer.com/listing/1973-datsun-240z-254/#comments

A 280ZX at PicknPull in Lynnwood WA. With the rare 2.7 liter engine. Looks like it still has the engine. Might be worth a look for a parts picker. https://row52.com/Vehicle/Index/JN1HZ06S7CX430334

He didn't do a very good job, obviously. You can stack a bigger nut or washers or a socket over the lug/stud and pull the lug all the way in using the lug nut. It should square up as the bottom of the lug seats. Do each one separately. Those aluminum wheels don't like high torque, it will deform the metal around the hole.

I used heater hose and it worked fine. I think it was 5/8". There is a metal screen-like thing in the factory hose used for flame arresting if there's a backfire in the intake system. Dig it out and put it in the new hose. Since the top hose was cracked you should check the bottom hose also.

I'm saying that when the engine is idling high after it's been warmed up, and you think that it should be idling at a lower RPM, open the hood, and press the linkage toward the closed position. If the blade is fully closed and the idle stays high then it's not a linkage problem. If the idle drops, it is a linkage problem.. Just trying to use the process of elimiination. Yo have to do it when the problem is happening though, not when it's not.

Try closing the throttle blade by hand from the engine bay. The throotle bore can get gummed up causing the blade to stick. If you can close it by hand then you can focus on getting it to close by itself, like it should. Check that the throttle return spring is intact and connected. It's not uncommon for them to rust and break, invisibly. It's knd of buried behind and under the linkage at the throttle body. There's a weak spring on the blade itself and a strong one on the linkage. A real pain to get connected if it's off. . . .