Zed Head

Where did you get the drawings? What year and car are they for?

How about a neutrino? When I had that bad ECU it died immediately. So that would have been loss of injection. I've also had a failing EFI relay that almost stranded me, but that was a restart of a hot engine problem, not a dying while running problem. Many old electronic parts that might have a momentary failure. I think that the red and green wires have low voltage at low RPM. Probably no real "jumping" ability, you'd need contact with a ground. Have you examined the wires around the breaker plate? One thing that is unique to the idle condition is that the breaker plate is at its lowest advance state. The red and green wires do get worked a bit as the plate rotates in relation to where they leave the distributor body. People have reported problems there. Unusual though.

You have now entered the gauge hyper-awareness zone. Watch those needles. Try to remember exactly what they were doing just before it dies again.

That's a setting in the software though, right? Can't remember your system, but you have electronic timing control? The verification of what's happening during driving is the key though, as you suggest. Get those numbers.

Anyway, on a more practical level. For those thinking that they'll be able to travel outside the country soon. Maybe a cruise ship? https://www.cdc.gov/coronavirus/2019-ncov/travelers/map-and-travel-notices.html

The point is about policy. Often entwined with politics, but not the same. Many government officials in the US with a certain political leaning still made decisions based on science. As far as my posts, you have to watch the video. Dig in deep, then comment. Or at least click on the "Show more" link under his name and you can read a summary. Look at the graphical data. The UK is going to allow a large surge of COVID cases (if I wanted to invoke politics I'd mention how they're calling it Freedom Day). That's geography, not politics. The video talks about long COVID and it also presents the views of over 120 scientists (I think, not positive on number) who describe what is probably going to be the result of the decision. The scientists think it is a bad decision and will lead to a greater burden on the citizens of the country. And may lead to stronger variants that will affect the rest of the world. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)01589-0/fulltext Excerpt - "As the third wave of the pandemic takes hold across England, the UK Government plans to further re-open the nation. Implicit in this decision is the acceptance that infections will surge, but that this does not matter because vaccines have “broken the link between infection and mortality”. 1 On July 19, 2021—branded as Freedom Day—almost all restrictions are set to end. We believe this decision is dangerous and premature."

I think that Mike asked us not to get in to politics. Way too much rationalizing to be useful. We have real numbers and science now to guide decisions.

Wonder where sweatybetty's been?

This guy's presentation today is pretty fascinating in a macabre sort of way. It is what it is, but worth tracking. Won't be a surprise if travel is blocked. Plan ahead. Edit - actually travel is blocked right now. Not going to change soon, I'd assume. https://ourworldindata.org/covid-cases

I'd put the timing light on it and make sure you know the distributor is working right. I just remembered going for a test drive many years ago with a friend right after he did some work on his truck's engine, and he remarked that the engine seemed like it had lost power. We were climbing a small dirt hill at low RPM. I said it felt like the timing was retarded and he realized that he had left the vacuum advance hose off. Put it back on and the pep came back. Might be that you don't actually have any advance mechanism happening so you need 25 initial just to make it run half-decent.

Sometimes you can find these numbers on the internet. http://www.carpartsmanual.com/datsun/Z-1969-1978/electrical/electric-unit-switch/section-2/240z-260z-(from-aug-73) http://www.carpartsmanual.com/datsun/Z-1969-1978/electrical/electric-unit-switch/section-1/240z-260z

You could also unplug them, one by one, and see what stops working.

Unplug them and see if the shape of the plug and the wire colors match the drawings.

Did you take apart the horn relay? You never showed what was inside.

If the files are on Google Drive you'll need to change the access from private to public. Google Drive is surprisingly hard to use, not very clear. Right click on the image, click "Share", then change the setting under "Get link" to "anyone with the link" by clicking the tiny black triangle on the right. Very convoluted. If you're on a Windows computer you can copy the image to the Clipboard and just paste it directly in to a post. Or, you can save the image as a file on your computer and "choose file".

Not if it's just crapping out then coming back to life. And yes, the big box. They fail in different ways, but dying then coming back to life is one of them. Old "new concept" electronics. 1975 was the first EFI 280Z.

Your links don't work. What else can you say about the engine? Pistons and head combination, for example. I wonder if a low compression engine runs better with more advance. Seems like it might since the pressure isn't there to drive the combustion. Maybe you have dished pistons with a P79 head.

I had a 1978 ECU that did that when I was testing it. Died and restarted a couple more times then I had to jog home and get the original to put back in. Ignition modules do that too. Carry spares.

I would go through the usual confirming that all of the timing marks are correct. Is piston #1 really at TDC when the other marks are zero'ed, or are you assuming that zero on the damper pulley is correct? If you're at 25 degrees and you add in the typical 18 for full centrifugal advance you'd be at 43 degrees advance under acceleration. You should be getting detonation and knocking. Something's off. Does timing advance when you rev the engine and the light is on it?

When you say "run" do you mean idling, or cruising, or getting on it? And, define "crap". Carbs, EFI, engine details will help also. Not much to go on. If cam timing is on the money then stretched chain is not likely. The chain determines cam timing.

Here's another good one for graphical data. https://ourworldindata.org/covid-cases

Google still seems to be the clearest and most up-to-date though. Remember when Google was just a simple search engine? https://www.google.com/search?q=covid-19

The World Health Organization gives the global view. Their web site has a lot of new tools for exploring. https://covid19.who.int/