Zed Head

That's just one measurement of many. You need all of them. They're shown in the book. Since you got a high resistance the next step would be to measure the same at the AFM itself. The high resistance could be in the AFM or in the wiring harness and its connections.

No injector ports are shown. Is that bar meant to be a fuel rail? The nipples are confusing, with one in the middle and one on the end. Why would you want the injectors so far from the head? Is this just a thought experiment or are you really planning to build something?

Actually you did mention it. But it's not enough. Nissan produced a whole set of instructions for testing at the ECU connector. It tells you that the wiring to the AFM is intact. The 1980 guide covers everything back to 1975.

I still like this thought. It fits your problem. Get out the meter, crawl under that dash to get to those kick panel screws (one of them only needs to be loosened, not removed), and pop that ECU connector off. If the ECU doesn't see it it doesn't happen.

I converted mine to a "headlights on" warning buzzer.

Similar cars go low and high. This one did pretty well. https://bringatrailer.com/listing/1973-datsun-240z-246/

It's a clutch. Kind of a bummer but I'm not sure that you can get the parts anymore. I browsed around but didn't find anything. 240hoke might know if he's still around. Don't know if he was ever a member here. He was active on HybridZ. https://forums.hybridz.org/topic/52029-adding-clutches-to-the-clsd-r200/ https://hokeperformance.squarespace.com/vq240z-build https://www.facebook.com/hokeperformance/ Here's a Google search page that has some good stuff. Of course, a call to the local Nissan dealer might be worthwhile too. https://www.google.com/search?q=site%3Ahybridz.org+clutch+lsd+r200

It's probably a 1988-1989 turbo 300ZX diff. They're the unicorn diff for people looking for the easy LSD swap for their Z. The only long-nose R200 LSD diff in the states. 1990 went to the short-nose. This is from the 1989 PD FSM chapter.

Looks like the dimensions are the same, but the drain pet-ckok is in a different spot. Pulled out a 76 and an 82. https://www.rockauto.com/en/catalog/nissan,1976,280z,2.8l+l6,1209226,cooling+system,radiator,2172 https://www.rockauto.com/en/catalog/nissan,1982,280zx,2.8l+l6,1209350,cooling+system,radiator,2172 https://www.rockauto.com/en/moreinfo.php?pk=10332348&cc=1209226&pt=2172&jsn=384 https://www.rockauto.com/en/moreinfo.php?pk=10332540&cc=1209350&pt=2172&jsn=391

Somewhere out there, either in the FSM or the Owners Manual there is direction by Nissan that the pump might need to be primed if you run out of fuel. I took a look at what I have but couldn't find it, but I'm sure that I've seen it. I remember worrying about it when I ran out of gas on my 78 parts car. But it had an aftermarket pump and fired right up after I put a couple of gallons in. I assumed at the time that that the OEM pumps must be different.

What pump is it? Brand and model.

Where's the unboxing video...

Sounds like your AFM is not connected, electrically. Might be that the connector/plug fell off of the bottom. It happens. You can can check via the pins at the ECU connector to be sure.

I looked around a little bit and it seems like the manufacturers generally went to computer control of a simple fuel pump relay instead of integrating the timer. But it is a hot topic, so of course, people have filled the need. https://www.ebay.com/itm/174274213748?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=NmzUBVTDRzy&sssrc=2047675&ssuid=bBzFtXzvTQO&widget_ver=artemis&media=COPY This on Amazon, below. The words in search should find it. I don't like to copy their links they seem full of extra stuff. Could probably be made to work.

Define long-term. Hey, you're having fun. Just keep going. There's probably a fuel pump relay out there somewhere with an integral timer. Or try that timer thing in your first post. My 2003 Ford has a timed prime but I think it's controlled by the PCM (aka ECU/computer). EFI is all about emissions so the manufacturers went to great lengths to get everything perfect from the first crank. Have you measured the leak down rate on your system?

My good FPR's (edit - and fuel pump check valve) would hold about 20 psi for days. The bad ones would leak down to zero. Carry on.

I hope it's not so but that sounds little bit like a bad ECU. When it's running poorly do you smell raw fuel from the exhaust? One test/fix that people do is to bang on the side of it while it's acting up. There can be broken solder joints inside that lose connection. A few kicks or knuckle raps can remake the connection. It's not a permanent fix but it's a clue. Could also be the ignition module. The clue there is the tachometer needle. Does it jump around or read higher than it seems it should?

Didn't you check fuel pressure using a temporary gauge in the past? And it was correct? If it was mine, I'd pop the cover off of the AFM and make sure the vane is moving with air flow. Simple stuff, no tools required. Any chance you could summarize everything you've done so far with measurement numbers ? Too many pages to go back and read through them all. I see suggestions that I'm pretty sure have already been made. Plus your problem is different now. The title says "when hot" but now it's when cold. The main problem has changed.

The forum's search engine is terrible, if you've been trying to find things using it. Go straight to Google to get better results. I know that Fastwoman had discussed it in the past. It's not hands-free but it's close. https://www.google.com/search?q=site%3Aclassiczcars.com+fastwoman+momentary+fuel+pump

Are you saying that your fuel pressure is leaking down? Nissan added automatic pump priming in the ZX's. It often quit working though. I'd guess the timer is in the relay. Maybe you could retrofit a ZX pump relay. 1982 -

How does it run? The typical no-AFR-gauge sign of a lean mixture is bucking and popping back through the intake manifold at part throttle acceleration. Don't get too focused on the numbers on the LED screen. If you're certain it's lean you could try the resistance tuning for the temperature sensor, that was previously mentioned. You can insert it in between the bullet connectors on the engine and let it hang for a quick test. http://www.atlanticz.ca/zclub/techtips/tempsensorpot/index.html

I don't know why they've changed the name to "additive manufacturing" but if you use that search term you can find a lot. Stereolithography > 3D printing > additive manufacturing > goofy. Pick a name and stick with it! Metals are possible. https://www.additivemanufacturing.media/kc/what-is-additive-manufacturing/am-materials

I'd check the coolant temperature sensor resistance. Compare to the chart from previous. Check at the ECU connector.

Could be the front seal or the front cover gasket. Both require removal to fix. Use a piece of wire or a long skinny stick in the fill hole to see how low the level is.

Do it again!