Zed Head

Did you post about this before? Seems familiar. A dial indicator, or even a stick on a brick, might tell you something. Set it up and spin the various items in question.

This is the typical sign of a lean situation, except that it happens under load. If it happens with no load that's pretty bad. Worn out cam lobes also cause popping back through the intake manifold. I've had it on V8 engines. That happens with no load. You might pull the valve cover and see if you have any loose rocker arms/damaged cam lobes.

Don't overlook the EGR system. Sometimes it leaks internally. The smoke would just head down the exhaust pipe. Even if you removed it and put a plate over the holes (I assume that you did, if your engine's had it), the passage walls sometimes rot out. ckurtz2, you could be here for quite a while. If they won't even put the vacuum line on the FPR, flow-matching injectors seems quite a stretch. Good luck though.

They're in the Distributor section of the Engine Electrical chapter of the FSM.

I don't think that anyone can really tell what you guys have installed on your engines. Ogs said he put his hand over the AFM, things changed, he installed the stock air box, things changed. "Normalized". Not sure what any of that actually means. The vacuum line reference to the FPR is a basic of ALL electronic fuel injection systems, not just early 70's Datsuns. The computer programs are designed to work with fuel pressure that varies with intake manifold pressure. You need that vacuum line. Just because the engine runs doesn't mean that it will run right. The best way to learn about early EFI is to get everything spec'ed in the way that the engineers intended. Then mess with it and see what happens. Messing with a messed up system just makes more mess. No offense. ckurtz2 wrote a whole page describing his experience with early EFI and you guys just blew right past it. Everything that he wrote is true. The fine details make the difference. There are many many stories on the web from people who just gave up and put carbs on. It's a challenge.

There is a ton out there on the old internet about the mounting flange being a ground circuit. Guys have disassembled them, examined the circuits, drawn them out, and explained them. The sheer mass suggests that it is correct, but I can't find an official GM document. An electronics guy with a meter, and maybe a battery, could probably confirm it. I did find one thing that I had forgotten about - the two plastic locating pins on the bottom of the module. You need to cut those off so it lays flat, so that you get good conduction in to the heat sink. A pair of wire cutters works, the plastic is not too hard. I mounted mine across from the exhaust manifold on the fenderwell because there was a nice threaded hole there. Can't remember what it was for originally. So I built a small heat shield that I hung (hanged?) from the intake manifold. Just being careful...

Should be about 29 - 31 psi with engine running. That would mean that the vacuum reference is not fitted to the FPR. Which mean the engine is tuned lean and when you open the throttle the fuel pressure does not increase like it should, leading to a lean stumble. You need that vacuum reference on the FPR.

Two pictures show E88. But it has injector notches. I know that Nissan did things differently in Europe but I've not heard of that. A fuel-injector E88 head. I've heard of carb'ed N42 heads but not this. Maybe @jonbill knows. Or @EuroDat

I think that it depends on how good the mounting surface is grounded. It might be why the distributor has a ground wire attached (that sometimes gets left off). Who knows, it might be why your E12-80 failed. Can't hurt. A meter reading will tell a lot. Even if you use conductive paste the heat sink will need to be grounded. So it's kind of a question of which bolt is doing what.

Here are two testing manuals that will help. The 1980 book covers all of the years through 1980. The first one was written specifically for the 1975 year. Not sure of the 1980 book has any changes.

Actually, they look separate. The engine will run without the alternator even attached. The multiple turns of the key looks like an ignition switch problem. The alternator and voltage regulator work together to produce charging voltage. The "black goo" might or might not be bad. Your meter will tell you if the the charging system is working. You need to learn to love electrical work. The early EFI systems are full of it.

Make sure that you have a good path to ground through the mounting hole grommets. That is the main ground for the coil charging circuit. The 4 pin module is actually 5, essentially. That is probably true for the E12-80 module also. The manufacturer instructions/labels don't cover that because they expect these parts to be bolted on to the distributors.

Where is initial timing set? Is the AFM vane moving immediately with the throttle opening? Is the 36 psi at idle with engine running or engine not running? You or your friend should write down the basic essential tune-up numbers as a starting point. The video kind of looks like there is still a big vacuum leak and the AFM vane is not reacting quickly. By the way, I don't know how those "phone size" short videos are made and posted but they suck. You can't enlarge them to see detail. Better to just create a full size video.

I matched the module with the coil it came with. A solid coil (not oil-filled), 0.6 ohms primary resistance, and a factory spec. module. The Pertronix module supposedly passes more current so the coil will build its field faster and you'll get better high RPM performance. But, when you're selling aftermarket you have to differentiate. Can't just sell the factory part for more money. So, with the high amp module they want you to run a corresponding Flamethrower coil. But they don't tell you which one corresponds. https://pertronixbrands.com/pages/pertronix-ignition-hei-modules "These modules provide enhanced high RPM performance and when used with their corresponding Flame-Thrower coil, substantially increase spark plug voltage" https://cdn.shopify.com/s/files/1/0247/6913/4628/files/D2000.pdf GM 4-PIN MODULE Intended for street/strip applications 6.9 Amp module

Pretty cool how they used to combine simple basic mechanical and physics concepts together to accomplish a goal. Today it's all converting lines on paper to lines on silicon. I came across this guys Youtube channel a while ago. Seems to be a traveling electronics engineer with free time. Here's one of his videos, he takes things apart and explains them. I am not claiming to understand what he's saying, but things can be learned.

Since you're on a roll can you explain how the regulator failing affects both gauges at the same time. Maybe even explain what is happening and if a regulator failure matches the symptoms described. Nissan didn't mention a regulator for the temperature gauge but I assume that's what the three triangles indicate. A shared component.

I don't know how the internal "voltage regulator" works but Nissan said if both gauges go bad at the same time that's probably the source of the problem.

The Youtube "short" only shows you starting the engine. Not much info in it. In your first post you were talking about volts but as I noted you should have an ammeter in your car, if it's a 1975. Are you sure it's not a 76? The build date can be in 75 for a 76 model. The voltmeter came in 1976. Do you have a hand held meter? Volts and resistance? If not you should get one. There are good options available for about $30. You need it if you're going to diagnose electrical problems. Here's an ammeter and a voltmeter. Not sure what you're working with.

That video didn't download. Most people create a Youtube channel and upload their videos to it. Makes them easier to view. Sounds like a nice project especially if it really only has 36,000 miles.

No need to go to Xenon when this forum has the same files. https://www.classiczcars.com/files/category/13-280z/ Seconding the bad VR possibility. It's probably not a "parasitic" draw. It's a normal draw, with no recharging. And, the ammeter should sit at zero when everything is off. It will go negative when the system is discharging and positive when it's charging. The EFI and ignition system will draw current while the engine is running. If you turn off the key and it sits on the negative side then you really do have a draw.

I just read through that last thread again and it's pretty scary. Be ready to break a sweat just reading. The incredible expanding project...

I found the thread I was thinking of. It's actually just a portion of a longer thread. The weirdness starts at post #24.

Can't find it but this one is interesting -

Things will get more clear when you get that used damper and test fit it. The woodruff keys are available. There is a recent thread on the forum from a guy who was having trouble getting the damper on without pushing the key out of its slot. Some good details in it, I'll see if can find it. I wonder if those seal parts that you found aren't from a previous seal. That's a 280ZX damper on a 260Z. Somebody's been in there before. Here's the part number for the woodruff key. #10. Search the part number and you'll get lots of hits. Your local auto parts store might even have it. http://www.carpartsmanual.com/datsun/Z-1969-1978/engine-240z-260z/piston-crankshaft

The fracture surface looks oily. And not seeing how you get that "pointer" groove without some wobble. Could be that the damper rubber is gone. Who knows. We need to know.