Zed Head

Did you try this suggestion from FastWoman yet? This will test the electrical circuit from the battery, through the dropping resistors and injectors, to the ECU connector, but without the ECU in the picture. Break the problem down in to chunks, then break the chunks in to smaller pieces. Edit - It's not clear what you mean by positive and negative terminals. You said the ECU connector gets voltage but not clear if you mean the injector pins or elsewhere. Pin 10, for example, gets battery voltage to run the ECU functions. If the injector pins show voltage then your problem is either the ECU itself, or the trigger signal from the coil negative, or the resistor and tachometer circuit. You never did confirm that that the tach was working. The ECU won't work right without that circuit.

You could go stock EFI with the F54/P90 combination and be pretty well guaranteed of a good running 280ZX power-level engine, with the engine harness, ECU and AFM from a ZX (75-78 Z parts would probably work also). The 2.8 is 17% bigger than the 2.4. More power. Even with carbs. Sounds like you're trying to mix and match 2 blocks and 2 heads for some benefit. There might not be any. Even with the E88 for higher compression, I think that you would lose overall from the smaller valves. If you don't want to go with EFI, the F54/P90 combo with carbs would still be pretty potent, relatively low cost and fewer problems since the parts are already matched and working together. I assume, unless you're rebuilding the engines. If you're rebuilding, there's probably a better combination of parts out there.

Both sides of the injector circuit will have power. The transistor in the ECU allows more current to flow at the appropriate time. With the key On you will see battery voltage on both sides of the dropping resistors, both sides of the injector connector and all the way up to the transistor in the ECU. That's how circuits that work by grounding function. Power everywhere up until the very end, where the grounding happens to cause an action.

I actually learned the trick from some Tony D posts, but have verified that it works. I agree on the electrical. I was intentionally vague on the 11 volts. Let the OP do the troubleshooting to find out why there's not 12.6 at the connectors. Somewhere from the battery and its charge, and through all of the various connections (fusible links, etc.) there is a cause for the lack of voltage.

I missed the green and red LCD comment, which does suggest that the ECU is grounding the injector circuit. I took the title at face value - "no pulse to injectors". Sounds like the real problem is "no gas from injectors." To add one more to FastWoman's list - 11 volts might be too low to get good current through the injectors to get them opening correctly. You should have a full 12.6 volts (fully charged battery) at the injector connectors. How long has the car been sitting? There have also been cases written of, where the injectors are so gummed up from sitting that they won't open. Another way to check if your ECU is "seeing" the coil and triggering the injectors, is to connect a jumper to the negative terminal of the coil, turn the key to On, then repeatedly tap the jumper to ground quickly. The ECU will fire the injectors on every third tap. It's quick and easy because there're no other noises like the starter cranking or the engine turning over.

The ECU is connected to the negative terminal of the coil through Pin #1. That's how it "knows" when to ground the injectors, allowing them to energize and open. Make sure that you have continuity from coil negative to Pin #1 at the ECU connector. Also, the tachometer and its resistor have to be in place for the ECU to work correctly, If your tachometer is not connected or if the resistor has fallen out, the ECU will not fire the injectors.

If you put the springs on with the shoes sideways (you would be looking at the face of the shoes), you can then use two hands to lift the whole assembly up (both shoes and all of the springs assembled), get the shoes aligned on the backing plate, then open them up like you would a book to put tension on the springs. After that it's a game of getting the retainers in without the "book" closing on you, the shoes falling off their pivot points and having to start over. A knee on the shoes works if you're flexible. Just another way to look at it.

Did you also post over on Hybridz? I saw a similar N42 head over there. It's definitely different from the stock domestic square port exhaust N42. My N42 head looks like the E-Bay head. That looks like water passage rust damage in Picture #5. There might be more in other water passages. I've read of rust eating all the way in to the exhaust port. You might look a little deeper in to how much rust damage is there.

My 76 starter (old-style non-reduction type) made a kind of shouting "look-at-me" kind of groan after starting, for a little while. I took it out,took it apart, spent an hour or two looking for some sign of what could make the noise while cleaning things up, then saw that the bushing in the nose of the starter housing was pushing out. It was about half-way out and must have been letting the shaft vibrate and chatter inside the bushing. It looked like a bronze bushing press-fit in to the aluminum housing. I tapped it back in, staked it once with a punch to hold it, greased it up, reinstalled it and the noise was gone.

What beerman says. I've had several different half-shafts on my car (so the original orientation was lost in transit) and never noticed a vibration. Make sure the mating surfaces are clean and smooth,without any gouges or old dirt, so that they lay parallel and the bolts don't loosen. If you used a screwdriver or similar to pry them apart (not recommended but common, I'm sure) when you took them off, there might a be a small gouge or two that needs to be smoothed down. The wheel side has a raised ring that fits in to to a groove. Clean those up so that they seat properly.

Forum etiquette says that you should tell the people that helped you out how you solved the problem.

Forgot to add clutch, pressure plate (clutch kit) and flywheel turning if it's a manual. (See, that's how it goes...)

Just browsed through your thread. I think that questions you should ask and answer, considered all together, are - How soon do you want to be driving the car, how fast can you spend money, and how much can you (or do you want to) spend? The seemingly small pieces, like wheel cylinders for the brakes (probably corroded beyond rebuilding), flexible brake hoses (probably rotted), brake shoes, brake pads, master cylinder, clutch master cylinder, slave cylinder, suspension bushings, wheel bearings, carb rebuild kits, fuel lines (rotted), water heater lines, radiator hoses, headlights, bulbs, tires, and on and on, will add up to thousands of dollars. If the car has sat for 25 years, they all will probably need replacing. The cost will creep up on you as you work on it, you'll fix one thing, then realize the next needs work. Some of the parts, like 240Z wheel cylinders are pretty spendy. I think you could add up the cost of every part I listed above and add that to the cost of car, plus another 20 - 30% for machining work (exhaust manifolds, rebuilding heads, etc) to get close to what you'll really spend before it's even drivable. That's just from sitting, not including any existing damage or things you break while working on it (you will definitely break some of the old rusted pieces). Don't forget towing and licensing fees. If you don't have high cash flow, it could sit for a long while more before it's back on the road. Just another perspective. My one thousand dollar car has piece-mealed up to over four thousand spent just to get it to daily driver level. But it's a second car, bought mainly as a hobby.

It might not be clear in my response - #3 - that I was talking about the stainless lines that MSA sells. MSA sells lines made by Earl's. I bought the whole 4 piece set. They're labeled with a black tag of what looks like shrink tape that say's Earl's on it. You might be able to find the right lengths, made by Earl's, somewhere else (Amazon, E-Bay, JEGS, etc) but I went for the MSA convenience. They looked well-made, went on easy and did not require any post installation tightening and show no signs of leakage. They've been there for 20,000 miles. But they do come with the "Off-Road Applications Only" tag, as discussed.

Don't forget to adjust the points. They have to close and open to make and break the primary circuit in the coil. The condenser will stop your points from pitting and give you a stronger spark but is not necessary.

That's kind of odd, that you have the EGR casting but it's incomplete, with no fittings. Doesn't seem link Nissan would put that on a car for sale, do you know where he got it? It looks like the N47 pictured on this For Sale thread - http://forums.hybridz.org/index.php/topic/102684-turbo-engine-harness-50-n47-intake-60/page__pid__960869 I have an N47 intake though also, with the webbing in between the runners. There must have been two styles, early and late, as you suggest. Your stock throttle body should work, it will just be dumping in to a bigger hole.

I have used vise-grips on the body of the threaded cast steel and clamped them so that they rotated up against the cross member when I used my very large long-handled adjustable wrench to loosen the nut. I didn't want to put the torque on the ball joint. They can get pretty tight, even when I just give them a firm tighten, they have always been hard to get loose the next time around (I messed around with toe settings for a while, long enough to prematurely wear out a set of tires - zero is a good number). You're right, one thread is lefty. You can eye-ball it and tell which one, and which way is off.

Maybe you had the AAR plug switched with the CSV plug, and your recent work put themback where they belong. The AAR is powered when the engine is running. The plugs are in the same vicinity and are of the same type. I don't know how much gas the CSV puts out, but I think it's more than a typical injector. I have read reports of these engines running on the CSV alone. If you had the AAR plug connected to the CSV, the CSV would stay open as long as the engine was running. When you unplugged it, the engine burned off the excess gas, leaned out and died. From where you're at now, I would confirm spark, and make sure that you have 12 volts at the injectors. If you have those two, then confirm that the injectors are firing, through the ECU ground.

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.