NewZed

The FSM's don't even show an open option. http://www.nicoclub.com/FSM/Q45/ It will be expensive. You might consider the other LSD's, like the Subaru R180 option: http://forums.hybridz.org/topic/78123-subaru-wrx-sti-r180-side-axles/ http://forums.hybridz.org/topic/111779-betamotorsports-subaru-stis30-side-axles-wolf-creek-racing/

Pretty sure both of those rely on the CAS signal. The ECU (ECM) gets the CAS "triggers" (more than one maybe) and causes the power transistor (ignitor) to cut current to the coil to cause spark, and grounds the injectors to cause squirt. Different times of course. Have you gone through the troubleshooting procedures in the FSM? Once you're wired in, you essentially have an 87 or 88 ZX, just 280 intead of 300. Code 21 is on page 93. Even tells how to check the power transistor.

Looks like you were almost where you needed to be to answer the last question. Or at least tell you which pins have power and which ground. Probably paged right over it. There are other pin-outs shown, like EFEC 84 for the CAS. That's where I'd be if was in your shoes. http://www.xenonz31.com/reference.html Attached a sample.

Blocking the lines with bolts won't hurt anything. The hole in the back of the head is only used as a source of hot coolant for the heater core. If you block the lines the coolant will coolant wil just follow other paths through the head. 1977 uses an external voltage regulator. That might be the source of your voltage (charge light) problem, not the alternator.

The grease could have been there for heat transfer. The modules generate heat. You can buy a small tube of heat transfer goop at Radio Shack or an electronics store.

The "y" should be lower case.

You probably connected the BCDD wire instead. There's a three wire connector in the same area, if someone's had the wiring apart, the length of wire that goes from that connector, below the stock coil location, up and over to the sender might be missing. The wiring diagram will show youwhere the wire colors change also. Sometime colors change at connection points.

This option might be easier - http://forums.hybridz.org/topic/104419-s30-and-s130-wiring-harness-repair-kits-you-need-this-if-you-have-an-l28e-or-l28et/?hl=harness if you haven't torn things up yet. It gets good reviews. If I was in your boat and wanted to make the 78 harness work I would just open the Engine Fuel chapter of both FSMs and compare wires. There are small detailed wring diagrams in each, easy to understand and specific to the EFI harness only. Most wires will be the same, the ones that aren't might not matter. The fuel pump cutoff might be run entirely by external relays attached to the alternator and oil pump switch. www.xenons30.com/reference

Ignition module. Fuel supply. Overheating relay. Overheating electrical connection. You need to narrow things down. Watch for symptoms like what the tach needle does when it dies, lights or other electrical affected, etc. Do other thngs still work but the engine won't start or is everything totally dead? Car goes, car dies doesn't offer much.

Search over at zcar.com for user "skittle". He has a writeup linked in his sig for using the GM HEI module in place of the ignitor. Seems to work.

Is the connector pinout at the ECU the same for a Maxima L24E compared to a ZX L28E? Curious if you can just swap the complete engine with AFM in the engine bay and the ECU in the cabin and be up and running with an L28, no funky tuning or tweaking.

Maybe you just got a bad nitriding job. Too thin, uneven, too brittle...

Did it backfire? Timing might be off. "I've got a 78 280z". What's the rest of the story? When's the last time it ran?

Squirt some starter fluid in the intake manifold (pull a hose) and see what happens. If it starts then dies, your injectors may not be opening. If it doesn't start then you may not really have spark to the plugs or you have fouled spark plugs, which also results in no spark. Edit - it may also be that your Honda avatar is bad karma.

Up to somewhere in 1980 the 5 speed has the same gear set in 1 - 4 as the 75 - 79 4 speed. 5th is an engineered add on. So it comes down to your desired freeway RPM or top speed, if you're considering the early 5 speed. If you want the more evenly spaced 1 - 4 ratios, they only come in the 5 speed anyway. That's the other reason people swap the later 5 speed in. First gear is different between the early and late 4 and 5 speeds also, so the rear ratio can be important. The very early 4 speeds, 72-74, have a much lower first gear to match the 3.36 rear ratio. All of the options have a 1:1 4th gear ratio. Talking about the transmissions available on the factory Z's and ZX's, not racing options. Ratios are listed around the internet and in the FSM's. Coincidentally, read Post #73 in this thread - http://www.classiczcars.com/forums/open-zcar-discussion/40249-hls30-01222-project-3.html

There's a lot of good information in this thread. Were you just being extra cautious with the nitriding? Trying to avoid the new camashaft disaster? The comment above looks like Kinetic doesn't recommend it, but doesn't recommend against it either. But does say that the standard finish works best which implies that they've seen both in action. Googling "estas camshafts" brings up some interesting web sites also.

You might have the hoses at the rail switched, in the engine bay by the filter. That would pump directly to the return of the FPR. Note - I've only verified that an Aeromotive FPR won't flow backward, not a stock one. But I think that the general concept of regulation is the same. The fuel pushes on a much smaller area in reverse.

Maybe you connected hoses backwards at the tank. Pumping in to the return line instead of the supply line. The FPR won't flow backward, so you'll end up with the 90 psi or more that most aftermarket pumps will produce. Ot it could just be a loose hose clamp. Doesn't sound like you've looked to see where the leak is. "a hose beneath the car"?

The links are sized to the amount of current that they're designed to pass. They come in different sizes. This site seems about right for you, although the information about the red links is incorrect and/or incorrectly applied - http://atlanticz.ca/zclub/techtips/fusiblelinks/index.html

Here's a good start. You're right, there used to be something next to that link holder. Probably worth your while to figure out what the PO did to those wires.

The center of the yoke has a raised, machined portion that fits in to the machined center of the diff's pinion flange. It's a tight fit. Beat on it from two sides with a piece of wood or plastic/dead blow hammer to wiggle it out. If you use a chisel in the gap make sure to file or grind down the divot you create so that the you have a flat surface when you put it back together.

Does yours need a change just because it's time or because it has shifting problems? Some of the newer "syncromesh" fluids are lower viscosity (~5W-30) than the older fluids. They're designed for today's transmissions.

Curious - did you check wipe patterns while you were working on it? I get the impression that the guy buys used parts, shines them up, assembles them in to packages (custom?), then resells. You might have a grab bag of parts assembled to make one engine, with little atention paid to the important details.

Measure fuel pressure and check your cooant temperature circuit resistance at the ECU connector - sqwawk, cracker...

Sounds like you have a NAPS-Z engine. The two plugs are for emissions purposes. This is probably the wrong forum for your problem, have you tried any of the Nissan truck or Pahfinder forums? These guys seem to cover a wide variety of Nissan engines - http://community.ratsun.net/ You could probably convert to carbs with some work, but would you be able to pass CA emissions? http://en.wikipedia.org/wiki/Nissan_Z_engine