Zed Head

No power at 34 Don't necessarily mean no power at the fuel pump. Power to 34 is supplied though the fuel injection relay. The pump gets it's power from there also, but on its own line. You either have a messed up air regulator (AAR) or connection, not letting power through to Pin 34, which is only used to keep a fast idle for a short while, or no power from the EFI relay to the AAR, or no power to the EFI relay. No power to the relay seems most likely, considering your other issues. The EFI relay is the 1x1x2" silver box up above the hood release knob. Check the wiring diagram and you'll see the circuits. The AAR is an expensive item, and doesn't add much value. It's a convenience. You can check its operation by running 12 volts through it. It should close in a few minutes.

See the second paragraph in Post #4 again in this thread and think about it. I went through the same scenario, but I was sitting at 18 mpg for a long time, with signs of richness (gassy exhaust and dark plugs). Then, within a few days and one tank of gas (I do the math on each tank), mileage dropped to 15 mpg and the exhaust was full of unburned fumes. So I replaced the FPR with an aftermarket adjustable, set it to 36 psi and mileage jumped to 20 mpg and has been there ever since, with an occasional 21. For whatever reason, the pressure looked fine when I measured it cold, but during driving it must have climbed to high levels. I never figured out exactly what was wrong with the FPR. I had a theory that the aftermarket fuel pump (Airtex E8312) was pushing too much volume for the stock FPR but never confirmed anything. The new FPR (Aeromotive) made the difference though, in my case.

I was joking. Probably not DOT-approved as Leon says, but probably much safer than the rubber ones, much harder to cut and would probably drag a wheel and hub along if it broke off, saving nearby pedestrians. While you're doing the backs you might observe how the shape of the shoe fits the drum. I found that the shoes seemed to be designed for a larger drum. It took quite a few miles to wear them in to where they had good stopping power. I could feel them wearing by how far the parking brake handle moved (which is also the adjusting mechanism). Someone, cygnusx1 I believe, had some issues with weak back brakes after a brake job, recently. If I was doing it again, I would probably shape the edges of the shoes down with a file to get more contact. On the back brakes - it will probably be difficult to get the drums off.

Re the stainless lines - I bought a set and they installed with no problems and they are of high quality. I don't know who Earl is (the black tag on the lines) but he appears to be popular (has a variety of parts in the JEGS catalog), and appears to make some good stuff. Beware though - off-road use only! (the yellow tag). Don't get caught. If you've not had the brake lines off for quite a while, or ever, plan on spending some time getting the fittings loose. If I was starting your project I would go directly to vise-grips; wire-brushing, cleaning and filing to shape each nut line nut before clamping on the grips and breaking them loose. I would bet good money that you won't get a single one loose with even the best flare wrench in the universe. Plus the brackets will probably not hold the big nut on the fitting for the flexible line so plan on taking the clip off and using an an open end wrench.

No reason to cross fingers. That's why the instructions don't say "pump will be destroyed!" just "fuel will not flow". I would switch the wires first while you have the gasoline all sealed up. Less chance of a gas fumes meeting sparks. Plus it's easy and quick and will answer one question.

With the warranty (if you trust your mechanic) and the information, it looks like it's worth a try. Did you get an estimate on rebuilding your N47 for comparison? Since you won't be buying new cam towers, or maybe even a new cam, it might be cheaper for a refresh. The new head won't really be any improvement over a rebuilt N47. But if your head is warped or needs machine work, who knows. The N42, from what I've read, will be essentially the same as your N47. The only significant change was the liners in the exhaust ports, for emissions purposes, and, apparently, they flow about the same. Lots of good information on the Hybridz site. I believe that matching the valve heights is so that the same thickness lash pads can be used on all valves. Is the cam installed? If so, you should find out if the "wipe pattern" has been verified as correct. Also, with a new cam, you should read up on break-in procedures. Apparently, an additive that used to be common in motor oil, ZDDP, is not there any more and new cams have been self-destructing as a result (a hot topic but most are being safe rather than sorry). Search ZDDP or ZDP and "cam" on Google. Maybe someone who knows the cost of rebuilding a head can chime in. $250 for a drop on replacement seems like it might be a good deal. Edit - Just saw your pictures. That cam looks used, didn't realize that. Changes things somewhat. Since you have the head in hand, maybe you could find someone in the area who knows Datsuns for a second opinion. Good luck. 2nd edit - I don't know what a "new" Nissan cam looks like. Maybe new Nissan looks used? Maybe it's just the picture. Also, you should confirm that the the other valve seats were ground. It might be that someone just had two valves replaced on an old head, and you're just looking at buying another used head. It should work fine, it's a question of value now. Also, from what I've read on Hybridz, the square port headers and manifolds will work fine on round port heads, but not vice-versa.

It's possible that someone with an 80 ZX was going to put an N42 head on their F54 flat-top block, to get a higher CR (about 9.8). It's a fairly popular modification. That might fit the "N42 head on 1980 car" scenario. If that was the case, it wouldn't be surprising if they had a different cam installed, to lower cylinder pressures and avoid detonation, or just to make more power. If so, you'll still be on the edge with your stock EFI control system.

Not sure where the power steering pump comes in to play. That would be an odd way to seal a hole in the head. You said that it has N42 cast in to the side right, so really no reason to ponder the P79 option. It would be strange if a 1980 car came with an N42 head, although I've read that markets outside the US took longer to change. I think the old-timey phrase to describe what you're looking at is "a pig in a poke." If the cam towers have been replaced, then it's obviously not all stock parts. Does it have the stock cam or an aftermarket cam? Maybe someone installed an aftermarket cam, with the oil passage, and changed cam towers to fit. If it has an aftermarket cam, then your EFI system might have tuning problems, from what I've read. Even if it has the P79 cam, it might have problems, since they have a different grind, although I haven't seen an example of someone trying to run a later ZX engine on an early EFI ECU and AFM, so can't really say. Sounds interesting though, if you can get more information about what it is.

Now you're in to the fine details. The wiring diagram will help, and so will the FSM, and a multimeter or test light. I think that the black/white might be power to the coil positive. You can check by turning the key to On, it should have 12 volts. If you've already had the key to On and Start and didn't get any shorts, then you might as well turn the key to On and see what has power. One of your pictures looked like the fuel pump wires, so it's not clear how you could hear the fuel pump running. You can test them for power also, by holding the AFM vane open, with the key On. That's about all I have. Here's a link to a wiring diagram that's easier to use, from Saridout, a member of the forum - http://www.classiczcars.com/forums/showthread.php?36494-FREE-full-color-wiring-diagram-for-1976-280z&highlight=saridout+1976+wiring

It's shown on the bigger diagram that you cut a section from in an earlier post. Blue is labeled "L". In the engine bay, the blue wire is attached to the big ceramic ballast resistor by the coil and disappears in to the wiring harness. IT basically "monitors" what's happening at the negative terminal of the coil. You can check continuity from there to the Pin 1 connector at the ECU. Maybe you got your diagram from here - http://www.atlanticz.ca/zclub/techtips/wiringdiagrams/76_280z_wiring.pdf You can see the connections on the lower left by the coil, distributor and spark plugs.

No continuity will make the engine run very rich once it starts. It tells the ECU that the engine is very cold and needs lots of extra gas. Have you tried to start it again yet? If everything except the WTS is correct, it should start, run really rich for a little while then choke out and die in a cloud of blue smoke. If it won't start, check that the injectors are firing (although many cars will start on gas from the CSV, if it's working). The ECU grounds the injectors when it receives the "break" from the blue wire from the coil negative. Check for continuity between coil negative an Pin 1 with the key off. Or use a test light or test bulb to be sure the injectors are firing. Edit - forgot one thing - the tachometer circuit with its resistor has to be hooked up for the ECU to work correctly. It's on the blue wire from the coil negative also. If your tach isn't connected the ECU won't fire the injectors.

Sounds like you've lost power to your EFI harness (maybe, I don't know if the CSV is on the that harness or not). You should check for power at the injectors and at the ECU connector (Pin 10 I believe) with the key On. Check your EFI fusible link at the battery also, first actually, maybe the paint shop disconnected your battery to keep it from discharging and messed up the connection. It's probably running off the CSV alone, with no gas from the injectors. Find out why the injectors aren't firing.

I think, but am not sure, that one of those red wires is a dedicated ground wire for the EFI harness. The other is the power wire. If that is true, then you don't have a complete circuit for some of the components of the EFI harness. I think that you can confirm which is which by finding one of the components that is fed by the white wire in your wiring diagram and testing continuity back to the one of the red wires. But, yes, I think that you should have one red to positive and the other to negative. I just looked at my 76 to be sure. I wouldn't connect anything until I knew which red wire was which. From what I've read, it's not uncommon to be fooled by the red ground wire. Edit - I just looked at Saridout's wiring harness diagram and the red ground wire is shown leading from the battery negative. It should be also connected to body ground so you should have had a direct short if you connected your battery cables with those wires connected like that. Unless it's already been damaged in the past. According to the diagram, the red ground wire also connects to Pins 16, 17 and 35 at the ECU connector, and one of the legs of the water temperature sensor circuit. Don't guess and connect. My harness has some charred wires from POs' wiring work. 2nd Edit - actually it's shown in your copied wiring diagram also. A wire from the negative through a connector and on to 16, 17 and 35, etc. Both "R" for red.

You picture doesn't show where those wires connect. One of those red wires supplies your EFI harness (injectors ECU and relays), the other is a ground and connects to the negative post. The one from the positive terminal should have a green fusible link. If you can't get a link, consider an inline fuse holder. The green link is estimated at 40 amps. I would first determine which of those is the ground and which feeds the EFI harness, fix them up right,then continue testing. I don't think that you can test the circuits right until you get power to the relays.

When you say "axles" do you mean the axles that "clip" in to the differential or the drive shafts (commonly called half-shafts)? I believe that the 280Z axles will work if the 4.11 LSD has the groove and circlip in the splines. Some of the R180s uses bolt in axle, with a threaded "button" in the center. If yours has the groove inside, the 280Z axles will probably work, but I'm just guessing, I've never had an R180. There are some writeups on Hybrids about converting an R180 to the bolt-in style. You might do the reverse. Read about half way down the page here - http://forums.hybridz.org/index.php/topic/49194-differential-cv-lsd-hp-torque-r160-r180-r200-r230-diff-mount/ The whole thread is worth reading.

Tach needle drop first like rock or follow engine speed as car dies? Ignition versus fuel.

Nissan went to a solid all metal fuel rail in 1978. The only hose used in the rail is to connect the FPR, which is also a new design with only two ports instead of three, so if you find one you'll need the FPR also. It will bolt right on to any of the older 280zs. Not perfect, but simpler than the three piece design with all of the hose pieces and hose clamps.

There should be two fusible links more that are fed directly from the battery positive post. They are the the ones that supply power to your injectors and ECU. They're green.

Since you're looking for WAGs, how about the E12-80 module. From what I've read, and experienced, the electronic ignition modules seem to show different signs when they fail, but they all seem to have high RPM in common as a mode to bring on the failure signs.

Use search term "brake booster". All will become clear.

It might be just twisted and stuck on the mounting bracket or has undercoating gluing it in place. Wire brush the accumulated crud and give it a hard wiggle and it should pop free. But your picture does look a little odd. I have a 280 so don't know what the 240s look like, but my 280 doesn't look like that picture. It looks like there is some kind of sleeve over the end of the mounting bracket. Maybe even with a tack weld on it. Someone might have modified it so that they could tighten up the fitting. If the hose turns in the mounting bracket it can be a pain to get things tight.

There is actually a square-shaped piece of metal mounted to the the distributor body that fits in to a square hole on the bottom of the cap. The cap only fits one way. Apparently you only got one clip to lock. If the cap has been beat up while you cranked the engine, you might have done some damage to the rotor or the cap. Better take a close look at it. zKars is right, you'll need to understand a little more about the basics of the fuel injection system before you get it started, let alone running well. When was the last time the engine ran?

I'm not sure how the FPR mechanism would allow your fuel pressure to jump that high when you remove the vacuum hose, maybe some debris in the orifice, but that is very high fuel pressure. If that reading is correct, that is the pressure the injectors would see whenever you press the gas pedal to accelerate. It won't hurt anything to let the pressure sit at 40-50 psi. You should recheck it with the vacuum hose off to confirm. Without the hose it should be in the vicinity of 36 psi. I would check the FSM procedure for testing the water temp sensor and test it at the ECU. For some reason they split the tests up in to one description for continuity at the ECU, and another with actual readings at the sensor. Just take the resistance readings at the ECU and see if they fit the temperature chart in the FSM.

Fuel pressure just under 30 at idle sounds okay. Why didn't you give a number for no vacuum hose, instead of "really high"? The 1977 FSM Adobe file is harder to use than the other years since it's not broken in to chapters, but if you can find the Engine Fuel section, there are some great diagrams of where to place the probes at the ECU connector (with a numbered pin picture), how to set your meter, and what resistance values you should see. The 76 and 78 test methods are the same so you could download one of those FSMs to make it easier. Practice measuring resistance across a light bulb filament or similar if you aren't familiar with using a meter. There might be a water temperature switch up there also (there is for 76, not sure about 77). Make sure that you have the right bullet connectors. The switch is either open or closed based on temperature and determines which pickup coil the ignition system uses (if you have the dual pickup distributor you should have the water temp switch).

If you had read the Emissions section of the FSM, obtained from the links sent or the offer to send one directly to you, you'd know that the valve circled in yellow is part of the EGR control system. There's pictures and everything.