Zed Head

Sounds like a corroded contact point, or bad ECU component. Too bad you're not a hoarder yet, you'd have a spare ECU to try out. Another thought on diagnostics - light bulbs in parallel on suspect circuits. If the light goes off, that's a sign. On the positive side - you only have to wait 10 to 15 seconds before you can try something new. 20-25 seconds round trip. You can check everything in one hour.

A thought on a possible diagnostic tool. A spare tachometer or a meter with tachometer or frequency measuring ability attached to the coil, or the ignition module blue wire in the cabin (so you can see it easier) might tell if it's the tachometer failing or spark disappearing. That's always the first split in the trouble trail - fuel or spark. It would have to be visible so you can see immediately if you have spark when trying to restart or when it dies.

Nah, I know it wasn't running because I had just jumped back in after about an hour and a half and distinctly remember that feeling of "what broke this time" when it didn't start. Then looking over to see the resistor laying on the passenger floor. I had just done some work under the dash, putting in a relay for the lights, and the resistor was unwrapped because I had wanted to see what it looked like. Months before that I had the tachometer out and wanted to move the car but it wouldn't start. Reinstalled the tach and it started right up. Also did the same thing on a 1978 parts car that had a running engine. Used to start the engine every few weeks and it wouldn't start after I removed the tach. BUT. Someone else will have to test the factory stock system, which is what I used to have. Because I went out this morning and the engine starts with or without the resistor. So now I have to add a disclaimer whenever I talk about this. One thing I had wondered about was the need for some transistor systems to have power to one side to lock in the logic state. Maybe the stock system needed that and my GM HEI module doesn't. Or it's more robust and needs less or can handle more. While I had the resistor out, I measured both sides of the circuit, because if you look at the BE diagram, they draw a little square component with fused power to one side and the coil negative power on the other. Both sides had battery voltage, even though the tach side can only get it through that little square. this is all with the key On, engine not running. That's all my spongiform electronics knowledge can come up with. If I ever get another stock 280Z I'll probably test this again just to know, before I start modifying.

The pins aren't connected to anything inside are they? Probably pre-made connectors, wasteful manufacturing. Maybe ran out of the other stock and used those to finish an order. I have one of each of those too, a full set and one pinned to match the diagram. Interesting that there are now three styles of the mystery parts - black cooling fins, raw aluminum, and none.

I've seen mention of Honda XL500. http://www.wiseco.com/ http://www.japbikespares.com/honda-xl500-oversize-piston-kit-rings-pin-clips-89-5mm

If the engine is complete enough you could hook it up on the garage floor and start it to see how it sounds. Might tell you something about condition. As far as tear-down, there are different levels. You can learn a lot just by looking at spark plugs and the cam shaft, and the crankshaft. If things look in good shape, you might decide to leave it alone and swap it in. I like to take things apart too, but things almost always break in progress. And, even the simple stuff will cost you substantial money. Head gasket, head bolts, intake/exhaust gaskets, etc. Just offering the "don't do it" view. You might end up with a pile of parts.

The possibility of a wiring diagram error did pop in it to my head last night (again, I think it's been in there before). I might pop that resistor out and see if Pin #1 still has a path to the coil. We might hit 70 degrees here today. Weird weather. If the resistor is inline with Pin 1, instead of branched, that would explain why no resistor caused no-run. BUT, I discovered the phenomenon when I tried to move my car with the tachometer out. Anyway, one of those puzzles "Ground by wire" would have been more descriptive. My meaning was more that it doesn't depend on a ground through the mounting bolts, although it may also ground there. It's been in the back of my head that it could just be an ECU problem. But, the weird tach behavior is there. I hope a clear answer and solution comes out, even if it's just localizing the issue to one component. Nothing worse that a problem that disappears for no reason.

I would check the ground wire for the tach first. If the tach is losing ground it would be like disconnecting the tach. If everything looks right though, and you want to try running it without the tachometer, in case the tach is causing the problem, then try grounding the resistor. The fact that you still have spark but the tach stops working seems to show that you're losing that path to ground. Either because the circuit is broken inside the tach, or because the tachometer's ground wire is bad. And I know that the EFI engine won't start without the tach. It might cough a few times from some cold start valve fuel but won't run. I had the resistor fall out on my car once and the engine didn't even pop, but I don't have a CSV. I put the resistor back in and it fired right up. I've repeated the experiment, on purpose, since then. Some people don't believe it, but it's easy to test. Pop the resistor out - no start. Replace - back to normal. Anyway, that's just some background Keep looking at diagrams and testing parts and something will crop up. I know someone who had a corroded fuse that would overheat just from current flow, causing everything to shut off. Sit for a few minutes and it would start right back up. That was a BMW though.

So here's a possibility - your tachometer might be losing ground, or failing, causing a loss of ground on that wire. From my own experience, the EFI system's will not work if the tachometer is disconnected. So the "trick" i mentioned would be to find the resistor under the dash, disconnect the side that goes to the tach, and connect it directly to ground. I ran an engine in my garage like this with no problems. The resistor is very high resistance so no chance of burning wires. superlen or Captain Obvious or SteveJ might have some thoughts on why the computer needs the tach to work. All I know is that they need it. You might also check the tach's ground. The wiring diagram shows a dedicated ground wire through C1 for 1977. Page BE-31.

The ECU's pin #1 is on the same wire as the tach signal. I wonder if a bad tach could cause the ECU to stop working right. Or if a bad ECU could cause the tach to stop working even though there's spark. Yes, sometimes you can stuck in a weird place. Have you tried tapping/beating on the side of the ECU when it dies? Others have reported that that has temporarily fixed bad ECU connections. The solder joints crack and lose their connection at the main connector. I know a trick you could try to take the tachometer out of the picture but it might make you uncomfortable.

I thought you might be able to remember the pattern of the bolts, tightening two that were close together or six evenly spaced. Anyway, you can always return it and start again. OReillys will usually bring parts in just to look at. Might be worthwhile to just have them bring both in. Don't forget to drain the new fluid, for reuse, before taking the trans. back out.

One last thing - there are two sizes of clutch, 225 and 240mm. The bolt patterns of the pressure plate assembly are different, and the height. Do you know which you have? Some people use the 240 mm for performance applications. They came stock on 2+2's and the later ZX turbo cars. The visible difference is that the 240 has 6 evenly spaced mounting holes and the 225 has 3 sets of 2 closely spaced holes. The factory fywheels only fit one style each. So if you ordered the clutch for the car model, or the transmission, it could still be wrong. More to worry about.

Look through the link in Post #5. It shows how to take a measurement that will tell you how far off your collar is.

It's happened before. You probably got the collar and bearing with the transmission and the pressure plate and disc separately, right? Bummer. Hopefully the parts didn't take too much heat. Some clutch kits come with a collar included so there's no mismatch possible.

Here's another - http://www.classiczcars.com/topic/44389-l28-is-toasting-my-240z-clutch/page-2 92-95 mm from the fork surface of the collar to the flywheel surface is the key. That puts the end of the fork in the right spot for the slave cylinder and its rod. By the way, when Diseazd says "clutch" I think that he's talking about the whole assembly of pressure plate aka "cover" and clutch disc. The pressure plate and its cover come in different heights, that need different throwout bearing collars.

Neat. But it looks like an ad for a shop. If it is, the OP should just say so.

Don't wizz off the carb guys! They have the answers! These carbs are not like many, in that they have pistons inside, with damping oil to control their movement, and require exquisite tuning to work correctly. `Seriously, they are different from a USA-type Rochester (for example) carb. If you don;t have the right oil inside you might have problems. Post a new thread with "Problems with SU's " in the title and you'll get some pros to take a look. If you've covered all of the basics, carb problems are likely.

You say "throttle wide open" but later it looks like you mean "throttle pedal pushed to the floor". What's really happening at the carburetors? And what type are they? That might be the key. Also, what do you mean by "shot" with reference to the three plugs? And "turn over" is what the starter does. "Fire" would be descriptive of the engine trying to start. And, although it probably doesn't matter, one person's "good" is another's "maybe bad". If you got numbers, you might as well throw them out there. If you're checking compression with your thumb though, that's a problem. Numbers are always good to look at. Full disclosure - I haven't had a carbureted car since 1995.

Br means brown. This comes up occasionally. I'm guessing that the early "Brown" Nissan links looked red. Then people went by color, not the letters, some web pages were made, and we're locked in to Red forever.

I have some of that foil covered bubble wrap hanging and placed in strategic spots in the engine bay. My HEI module swap was getting kind of hot (I mounted it on the fenderwell, line-of-sight to the exhaust manifold) so I hung some insulation from the edge of the manifold just to test. It works well, reflective and insulating, and the base materials have a temperature rating of about 230 F. It's still there.

Most of what you describe sounds like a bad tach. But the thing with the clutch pedal sounds like a loose or shorted wire, in the vicinity of the clutch pedal. I don't think that there are any electrical switches at all on a 77 Z, so mechanical movement of something is the only other option. The wire to the tach has a high ohm resistor inline so it could probably be dead-shorted with no fuse-blowing or wire-melting. I'd look around under the dash. Not really sure how the blue wire could be affected but who knows.

EuroDat supplied one in Post #2 of your other thread. You would just need to extend and connect the red and green wires from inside your distributor to the red and green wires that run to the old TIU by the fusebox. The E12-80 is essentially just the big TIU reduced in size and moved to the distributor body. And even though the inside of the distributors look different the old 77 and the newer ZX type both use the same triggering mechanism. The red and green wires are the key.

All three of these are different, but all three have some similarities. Look at what looks like a screw terminal at the top. Mine and your "modern" unit have the same number of filled spots. Your older one has many more. But mine and your old one have the same heat sink parts (I don't know my parts...). And the circuit boards themselves are all three different. Edit - actually the later lots, mine and yours, have similar circuit boards. But different parts filling the holes. Probably made at various subcontractors to some performance spec. Maybe.

Here's Lot #8107. No clues here. I don't think I've seen any with the shiny new parts yours shows. They all have the circular heat sinks. Maybe yours is a rebuilt unit.

That is interesting, They build to specs. though, maybe the component quality just got better. I have several of those, if I have a later lot number than the first one, I'll open it up and see what's in there. Maybe there's a certain break-point number to look for, to get more modern parts (designed 39 years ago instead of 40). The ECU doesn't control the fuel pump relay, the AFM switch does. Although I think there are some diagrams out there that show some interaction with some ECU pins. But there are also errors in the early ECU wiring diagrams. Pins that don't exist. Somewhere out there is a list of what the various resistors and capacitors do. But the work needed to make changes is difficult. Easier to just add a potentiometer to the coolant temp. circuit. Change the inputs, not the ECU parts.