Zed Head

You're right. I even forgot that I gave somebody the same advice just a short while ago, that there was no guarantee the PO had it right. Even referred to it in my post above, "people get it wrong all the time". They get the oil pump installed wrong too. In that previous thread, the PO did have it wrong and the new owner put the wires where they were supposed to be. When he put them where they weren't supposed to be it worked like it used to.

Considering that the car had some questionable work done to it and probably sat for a while, have you changed the fuel in the tank? If it sat for over a year, it could have bad fuel. Also, fuel pressure is critical to proper operation of these systems. The tanks are known to generate rust and cause fuel pressure problems. Worthwhile to measure it. Good that you've already solved some problems and know more about the state of the engine. Might be worthwhile to tell as much as you can about how long you think that car sat, what, in detail, you've done to it since you got it, and how, exactly, it's running and driving.

Actually partial should have been many many ohms, like kohms (kilo-ohms, thousands) or infinite, and full should have been low, as shown. For Test 1 (2). But you're only saying open, not fully open. So not clear if you had the throttle wide open or only partially open. Either way, that measurement would show full throttle to the ECU, adding extra fuel. When there's continuity (very low ohms) on 3-18, the ECU adds a lot of extra fuel. Not clear what "running badly" means either. Is this driving, or idling, or revving? At least you know the timing is correct, Although you didn't report the number,or if it advances like it should when revving. Sorry, we've asked you step in to a messy world. But you know some things for sure now. I copied the test I think that you mean by Test 2. The TPS has three states - idle, not idle (partial), and full throttle.

Cars drag a pocket of dirty air behind them. The air passing over the sides of the car creates a pressure differential inside the car. The air pocket at the back is higher pressure than inside the car. So whatever is in that pocket of air will be pushed inside, through any small holes The hatch framework has holes that can't be sealed easily like where the latch attaches. The big vinyl covered panel on the inside of the hatch lid is open to the framework. It can be be sealed to stop the air flow. Simple adhesive weatherstrip will do the job.

Dave gave a good list. It looks long but each item is simple. Things get overlooked like the fact that the crankcase (the valve cover) is connected to the intake system, through the PCV system. So even a missing dipstick is a vacuum leak. And the tests at the EFI plug are simple "poke and read the meter" tests. Just resistance measurements. Grab a pen and paper and write down what you measure also. People often come back and say the numbers checked out, but don't say what they were.

You've reached thrashing about stage. Once you get here it's best to go back to square one and build back up. That would be to confirm that the plug wires are in the correct holes. Since you didn't remove the oil pump, it's probably safe to assume that the distributor is installed correctly. Take the cap off, turn the engine until the rotor is pointing forward and the timing mark is at zero. Then put #1 in and install the others in the right and order and rotation direction. People get it wrong all the time.

Correct ignition timing and firing order is critical.

Use this book to verify that the coolant temperature sensor is correct and connected, and the AFM. Your symptoms sound a little bit like the AFM isn't connected, and the engine is running on the idle enrichment only. http://www.classiczcars.com/files/file/31-efi-book-1975/

Everybody's just recommending that you check that the carbs aren't gunked up. Even a dry carb will get some slight corrosion of the aluminum that can cause friction, if it's in a moist environment. They're sensitive creatures. Sometimes it's worse when they're off because they might sit tilted. Then the varnish sticks on unusual parts.

I think that IGN is actually the fusible link that supplies those fuses. Just realized something. IGN, ACC, HL, and the main link (BAT). Not sure what ST is doing there though.

Site had it in two posts, first page. Damn. Not sure why the fuel gauge fuse would power the VR though. Maybe the wire wiggling helped out. This is from the 1976 FSM.

Looks like two problems, the seal area and the fit of the propeller shaft yoke. I think that steel outer shield is a press fit. You might be able to get it off by twisting and pulling. Nissan got rid of it in later years anyway since the propeller shaft yoke has its own shield. Once that's off you can work on the aluminum if needed. Once it's close though I'd take Euro's suggestion and just seal up the outer edge of a rubber seal and drive it in. You'll break the edge off if you do too much to it. Not an uncommon problem.

How long is "a while"? And where did it sit? Did you remove anything besides exhaust when you replaced the exhaust? These kinds of problems are usually caused by the stuff that you're sure can't be the reason.

There is no "they" it's just one guy named Al. And he will spin you a story. His member name on this site is URGELUS or something like that. He's saying that the ZX starter is stronger and lighter than the Z starter. Which it is. But you can buy the same starter for less money elsewhere. Al sells inexpensive stuff for a high premium. The real question is how he stays in business. The answer is people who fall for his stuff.

It's a shame that Wheeler Dealers bought in to his hype and have added life to what he does. https://www.californiadatsun.com/california-datsun-parts-blog/wheeler-dealers-240z-restoration.html?highlight=WyJzdGFydGVyIl0=

Here's the two starters you're looking at. $75 for a polish. https://www.californiadatsun.com/starters/datsun-z-240z-280zx-510-heavy-duty-reduction-starter.html?highlight=WyJzdGFydGVyIl0= https://www.californiadatsun.com/starters/datsun-z-240z-280zx-510-polished-hd-reduction-starter.html?highlight=WyJzdGFydGVyIl0=

Like site says, other companies use the Nissan gear reduction starter as a high-performance unit, by installing a different nose on it to fit other engines. That's just a shined up and painted gear reduction starter from CD. Probably from Rockauto. Browse his other products and you'll see that most of them are just inexpensive parts with slight modifications, and a huge price increase. Distributors with a mounting block added - 3 times Rockauto cost. https://www.californiadatsun.com/distributors-and-parts/datsun-240z-280z-e12-80-rebuilt-electronic-distributor.html?highlight=WyJkaXN0cmlidXRvciJd The factory gear reduction starters work well.

Should also note that people get bad alternators straight from the shelf. That's why they have a lifetime warranty. But if you're not getting power at the T plug, the alternator can't work. That's probably where your mechanic is stuck. Since the engine runs on the battery, focus on that.

Dave WM's has the P terminal also, in his video, I see. The reman companies have consolidated their parts lists down so that just a few will cover a lot of cars. Looks like they're putting the P terminal everywhere now. Sorry about the misdirection. If you post some part numbers.... Can't emphasize enough how untrained the typical parts store employee is. All they know to do is key letters and numbers in to their computer and do what it tells them to do. Occasionally somebody will actually know some car stuff, but the majority don't. It's just the way things are. In the meantime, the Factory Service Manual has all of the testing procedures for the stock system. Your mechanic really needs to go there. It's free! http://www.classiczcars.com/files/file/22-1975-280z-factory-service-manual/

Good luck. By the way, I'm not really sure the P terminal is for. But it didn't show up until the 280ZX.

Here's the thing though - they have to set their test machine up as either internal or external regulation, I think. I'd take it back and make sure you get a guy who knows what he's doing and make sure he tells you if it's internal or external. If you have a part number from the box it came in we could do some detective work also. Could be that the reman guys are packing different things in to the same cases.

Here it is. I think I took the condenser off and used it to solve a different problem, so it's not there. The P terminal is a tachometer signal that some ECU's use. Only heard of it on internally regulated units.

Can you find an S and an L over by the T plug? The yellow wire and the white/black wire. That would be the lock. But the "P" terminal is a pretty good clue also. I think that it only comes on the ZX alternators. Just took a picture of an OReilly Ultima alternator I had on the shelf. Looks just like yours. It's a ZX unit. I'll post a picture in a second.

Is it possible that you're too far down the line? Looking at outputs, but not inputs. Maybe go back to the start of the sequence of events. Is the CAS signal getting to the ECU? That would be the "engine is rotating" signal, wouldn't it? Isn't that what the diagram means by "engine speed" sensor? I know many Bimmers use the variable reluctor wheel on the damper. You'll need to know that signal is getting through anyway, even with Megasquirt.

Just pulling out some more clues. Could be that the gauges have been out and didn't get reconnected. Also adding something for your mechanic. Even though there may not be an actual charge light, the L(amp) wire is still the power supply for the alternator windings, I believe. I assume that power comes in to the VR through L then goes out to F at the alternator. Looks like Y gets its power from GR which comes from an ignition interlock unit. Not familiar with that. Made my head hurt just following the L wire out and I still don't know how it works. Here's a full diagram - http://atlanticz.ca/zclub/techtips/wiringdiagrams/75_280z_wiring.pdf