NewZed

Did the links get broken during the move to the new software? They're jot Photobucket, they should be on the Hybridz server, I think.

Remove the gunk. Everything in that area should be steel. You don't want any gunk between mating surfaces of the wheel and/or adapters. Verify that it doesn't fit. Call zcardepot and get them to send you the right part. Why accept the wrong part from a zcar "specialist"?

Looks like you figured it out. 75 is the oddball.

Tire sidewalls, shock absorbers, and bushings are where the rough ride really come from. You mentioned tire series, but not much else about what you're running.

Nissan themselves eliminated one of the two sleeves when they redesigned the 5 speed for the 280ZX model. Leaving one on the propeller shaft but none on the the transmission. You'll just have opposite. The 280Z system is kind of redundant. If you ever get a ZX transmission you might want to fab one up. It would be easier to attach to the transmission in that case though. If the transmission cover extends over the base of the slip yoke you're probably fine. It will be like the ZX system in reverse. If there's a gap, things might get dirty. You might check fit before you get carried away. Edit - actually, by the picture, it looks like you'll have a gap. I'd extend the transmission dust sleeve slightly, easier. You could just run it though, and keep an eye on the seal. It's just going to get dirtier than if it had full coverage.

Nissan started staking the joints in to the shaft in 1975, directing owners to replace the whole shaft if there were problems. There are places that will modify the shafts so that the u-joint can be replaced. That's what he's looking for.

Worn wheel bearings, bushings, or steering gear are all likely on these old cars. Sounds like you haven't really checked anything out. Getting way ahead of buying another car.

When people say they did "all" of the tests, it usually comes out later that they skipped a few or didn't actually measure numbers, just continuity. Just saying, you have to be rigorous and detailed when you work on these systems. Good accurate numbers measured at the right times. For example, 35 psi on a running engine is too high, if you set the pressure while the engine is running. Besides that, if you don't show the numbers you got then people out here can't really offer good advice. Everybody says that they did everything right, so there's no wrong to fix. Also, 4.8 ohms is too high for injector resistance, so it makes you wonder where you got your specs. Although it alone wouldn't cause your problem. 8 psi is really low fuel pressure though. A fairly common problem is a blown FPR diaphragm. Of course, you'd have to have two bad ones since you tried two and got the same results. Just trying to help. Need more details. Are there numbers on the injectors, for example? That would be a clue.

Did you talk to more than one person? Can't imagine that the guy who designed it hadn't seen the press-in studs. Sounds like you didn't get far enough up the chain. Aren't the CV joints the weak link on many of the 930 style axles? The diameter isn't worth much if the CV joint fails. Torque and horsepower aren't the same thing. And multiple posts from the past have laughed at the 800 or 1000 HP claims. Nonsense numbers.

Have you tested the sensors that tell the ECU how much fuel to add?

He did a great job as a moderator here. He seemed like a really good guy. Looks like he was active on the site just recently, so it must have been sudden.

Some is normal. The retaining circlip has some play in both grooves. People have been known to lose the circlip or just not be aware that there's supposed to be one in there, and run with a loose axle. Take the nuts off and see if the axle is retained. You're sill misguided on your lug nut issue. Any play in the lug nut or stud area is bad. Any. There's no close enough. The wheel should be firmly attached to the flange, as if they were one piece. That's a basic of any wheeled vehicle, no fuzzy area to think about.

No problem. And I'm not your bud.

The loose lug nut thing is a big concern. How can you drive around with loose lug nuts and not know it? They were so loose you could feel the play be shaking the wheel by hand? That's a lot of loose. And there shouldn't be an "as much as I could" in there. There's either a torque value or you know from experience. Are you running steel wheels or mag wheels? There are many ways to have a bad wheel. Bent steel, or wallowed out aluminum on the mag, or lug nuts that are too long and bottoming out on. If you've identified a wheel problem, swapping to known good wheels for a test would save you a lot of time. You should spend more time on the wheels and make sure that they're right. I used a vise to press my bushings out, and only heated the metal behind the rubber to destroy the bond. Burning the whole thing is neat-o but really just makes a lot of unnecessary mess.

The easiest, closest thing to a bolt-in, option might be one of these - https://whiteheadperformance.com/performance-parts/datsun-240z-260z-280z-1970-78/240z-280z-diff-differential-axles-lsd/ They are hard to find on the open market, the CL's and eBay's don't have many. You can also get an open R200 and convert it to LSD with one of these - https://www.whiteheadperformance.com/?s=differential&post_type=product Neither of these are bolt-in because you'll need a different mustache bar, and modified propeller (aka drive) shaft. If you try to run all of that torque through an open R180 diff you'll probably just break it right away or it will wear out from spinning one wheel.

Here you can see that there's only 1.58" of travel combined in the two joints. Could be that your problem isn't too little travel, but too much, on the inner joint. 2 x "not much at all" = correct.

Your question has already been addressed then, you just need to use the answer in your response. Seems like you might be looking at your axle backwards. And 2 inches of travel in either direction would be 4 inches of total travel. I don't think that's possible.

You haven't really defined a problem, besides "very little", which, somewhat ironically, means very little. Also ironic, you need to be more articulate in your description. Seriously. It's not clear what the problem is.

You say unbalanced but you describe loose. Sounds more like a bad bearing or bad suspension bushings.

I didn't post earlier because you said that you were taking it to a transmission shop, but you might compare 3rd gear to 4th gear. 4th is powered straight through the transmission. while 3rd uses the countershaft. If you have a bad countershaft bearing you won't notice it as much when in 4th under power. You might also drain the fluid and check the drain plug magnet. Not uncommon to find bearing retainer pieces on the magnet. The adapter plate bearings go bad. Just noticed that you said 3rd or higher. There are also main shaft bearings in the adapter plate. The two in the front cover go bad also. Either way, draining and checking the plug will tell you something. Easy to do. Remove the fill plug first, to be sure that you'll be able to refill it.

I would focus on the quality of the signal on the blue wire to Pin #1 at the ECU. I've described my experience with the missing tachometer before and people have said it's not true, there's no rational reason for it, and they've also shown that their engine would start without it. And mine will even start without it now that I've switched to a different ignition module. But when my car was factory stock it would not start if the tachometer was not connected to the branched blue wire circuit. There was something about the balance of those three things on that circuit, the ECU, the tachometer, and the ignition module. I had it happen twice, once with a 78 parts car and twice with my 76 car. I even confirmed it by removing the resistor in the line to the tachometer, on purpose, to see what would happen. It wouldn't start at all, not even a pop. So, is your tachometer intact and does it work would be my next question. You've shown that you have everything else that you need, and the fact that it runs once it starts shows that everything is there. You're in the "bizarre causes" regime now. You might even swap tachometers or plug in another if you can get to the plug. Or swap ignition modules if you have another, even though yours works. I have solved tachometer problems by adding a condenser to the negative terminal circuit. The signal was noisy. and the condenser cleaned it up. Hook up your noid light to the coil negative terminal and see if it behaves normally or shows some weirdness.

By "crank" signal, you mean Start, right? Pretty sure that is for Start enrichment and won't stop the engine from starting. He has the FMS and the EFI Guide to show this, and he's already run some tests. He just needs to keep track of what's happening, when it happens. Especially now that he knows it's a sporadic problem. The part about the trigger from the coil negative is right. But that's also covered in both of the books he's been using.

You kind of answered your own question. It's not a "signal" to the injectors, it's just completing the path to ground so that current can flow through the injector bodies. Each time the path is completed, the injector opens. Then the circuit is broken and the injector closes. Electricity is very fast, it all happens in milliseconds. You're not reporting all of the numbers that matter. It looks like you have a fuel pressure gauge on the engine but you didn't say what it is when it won't start and what it is when it will. No offense, but you have to be methodical to make progress with the EFI systems. You can't just look at one thing at a time. Many things have to be right at specific times. You need to know that you have power to certain places, pressure in the fuel system, certain signals going where they should go when they should go there, etc. You should have a check list that you run through, either on paper or in your head. Correct power - check (look at your meter), correct pressure - check (look at your gauge) , spark - check (look at the tachometer, it counts sparks)... Forgot to say, I had a 78 parts car that would not start when the tachometer was out. Somehow it screwed up the circuit to the ECU, since it's on a branch of the line from the coil negative terminal. So there are some odd things that can happen when everything else is right. But you need to know that everything else is right before you get in to that.

Those will work. The shifter is the same for 4 and 5 speeds, up to the ZX's.

Edit - forgot to say that people have been known to grind out a hollow for the nose of the diff to get a proper fit. That will raise it some. Enlarge the side holes a bit, do some grinding, a couple of shims on the bar... Just to fill in, I made a picture. 5/16" shorter. They also have one that says V8 only. But it's cheaper. Can't really figure out the page - http://www.energysuspensionparts.com/search.asp?pg=1&stext=3-1108 http://www.energysuspensionparts.com/3.1158