Zed Head

As noted earlier, it doesn't really sound like the "heat-soak" problem. The fact you don't even get a pop sounds more like a spark issue. Are you still using the stock ignition module? With the ballast resistor? Next time, or right now, you might check for spark to be sure it's actually a fueling problem.

I think that I saw your post on another forum about the same issue. It will be much easier to just source a complete R200 differential. You have to take the whole thing out anyway to replace the ring and pinion. They're not like Fords or Chevys that can be serviced from underneath the car. The easiest direct replacement for you would be a 3.7 R200 from a 1979 280ZX. Everything will be the same as what you're using now (unless somebody swapped in a 1975 R200, which are unique in the driveshaft bolt pattern). Second easy is a Z31 R200. You'll need to swap the pinion flanges because the Z31's use a different bolt pattern (oddly, they use the 1975 280Z bolt pattern, apparently). If you want new there's always Nissan. Spendy. Here's the cost of a 3.54 ratio R200 - CARRIER-W/ :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com You'd have to ask around to get the part number for a 3.7. Good luck.

I'm thinking the same as EuroDat. The one that you saved is a switch that you won't use. Do you have the upper left item connected to anything? The lower right is for the temperature gauge in the car. Keep that one. It use's a yellow wire with a female bullet connector. Probably in that harness you had in your hand in Post #4. The one that you took off with the extra wire to ground is also a switch, I think it's the one for the second pickup in the distributor. Have you had the distributor cap off yet? You might not even have a second pickup. You don't really need that switch, the engine will run fine without it. It's a fine detail that Nissan added to perfect warm-up.

Can't really tell what this means - " replaced the sensors besides the one with the bullet connector" but you probably don't need the switch on the upper left, in the attached picture. Your 77 probably had a switched, two-pickup distributor, to control timing while warming up but it's not really necessary. You might remove it and see if the thread and hole size are correct. Thought that you were getting a different housing.

These last few posts are interesting (although painful to read in rossiz's case). ZXR616 has a header, as does siteunseen, the only two cases of "no problem" so far. ZXR616's case is a little bit confounded by the fans, but they probably don't run when the car is parked (do they?). I do things to my car that I wouldn't normally recommend to others, although the experiments are typically hidden so the car still looks good, but in this case I'll just describe my ugliness. If you get desperate to just know that the problem might have a solution, go to the wrecking yard and get 2 heat riser tubes from an 80s - 90s Chevy S10. It's a flexible fiber/foil tube that fits perfectly over the nose of the ZX fan. Get a one hour bathroom fan timer from Home Depot. GE brand. Get a ZX blower, or a marine bilge blower (Amazon). Mount the blower somewhere in the engine compartment, tape the tubes together to give the length to go from blower to injectors, punch sizable holes in them over the injectors, mount, attach and wire everything together. The purpose is clear so details aren't necessary. The tube will lay down right on top of the engine, the hardest part is squeezing it between the hood latch and the valve cove. But it's flexible. The timer is attached to the steering column. I reach down and turn it on whenever I park. I used a lot of zip ties for my experiment, which is still there because it works so well. I have noticed though, recently, that I get a little stumble sometimes, even with the fan on. I wouldn't be surprised if gasoline formulations are changing. But if I forget to turn the fan on, it's a guarantee that I'll have a serious heat-soak problem. On the stock ZX fan setup - apparently the ZX fans don't turn on much using the water temperature switch. Better to use a manual timer.

Different scene then. Before and after seems like where you're at. If it didn't make the noise before, but it does now, then you must have altered something when you were adjusting lash. Did you knock one of the anti-rattle (mouse-trap) springs off or bend it? Easy to do since they're right next to the locknuts. Their purpose is to keep the rocker arm tight on the pivot. So it doesn't make noise.

I have a noise from my #1 cylinder. It's been there for about 20,000 miles, no change. I also adjusted lash, and double-checked. And have excellent compression numbers, a smooth idle and otherwise great performance. I've kind of come to the conclusion that some rocker arms and their associated parts just move differently than others and are noisier. Or I have a loose part somewhere that is just noisy, but okay. I decided that noise is not a problem. I've also noticed that I hear odd noises more after I work on the engine.

Since it is a race car, I wonder if whoever started it cold didn't give it the old high rev warm up routine. It's hard to resist since you want to hear that race motor rev. I've seen many people do it over the years. I always cringe. Hard to see why the noise would appear after sitting for so long. On your compression numbers - 20/150 = .13. Cylinder #3 is 13% low. It runs better on 4-6, which fits the bad #3 theory.

Could be height on the two combined gauges - fuel/volt meter and oil/temperature. I noticed that the slot for the light to escape is tiny at the base of the tube the bulb sits in. The light path on the speedo and tach is different. It would be where the filament sits I would guess, and the MSA's sits higher. Still seems odd that you would get a big difference. In person, both of the lights looked the same. Bummer. Good luck.

Stuck timing chain tensioner? Just a WAG. Something that might stick while sitting, maybe. Didn't watch the video the first time.

I've messed with a few old stuck injectors and found that a rap with a light weight wrench or a screwdriver blade will break them free sometimes. Nothing to lose. Try to hit the solid metal base if you make an attempt. If you get to the point where you're considering replacing them, you might also jump the two pins at the injector with a full 12 volts. A quick jolt or two won't burn anything up but the higher current flow might create a stronger magnetic field to pop things free (although I'm not sure how much stronger). Don't short your wires, there's not much room in there. Connect the wires at the injector and make sure they're clear then tap the other end to the battery. Edit - apparently the magnetic field strength is proportional to current so a 12.6 volt jolt might have an affect. Edit 2 - just a note on why they might get stuck. It's a tight fit inside and the gasoline flows past the metal core of the solenoid plug and the pintle pin which seats in the pintle orifice. Dried or old fuel leaves gooey varnish behind, gluing things together. If you get it free, let it run for while and rev it up to get clean gas through to clean things up.

Bad gas? Today's fuel doesn't last very long.

Sounds like the injectors aren't opening. Try swapping injector plugs from a cylinder that works to one that doesn't. It's batch fire so it doesn't matter which is where. Also, try the long screwdriver stethosocope trick to hear the difference between an injector that's opening and one that's not.

I went out and compared Eiko to MSA and took the attached picture. Maybe you didn't get a good ground when you re-installed the gauges. Do those bulbs ground through the sides or do they have a dedicated wire? (I'll probably check myself right after I post this). They have their own wire. Weird that you get lower illumination. Maybe they popped out of their locations when you reinstalled the gauges. It's happened to me. Good luck. Eiko A72 on the right, MSA on the left.

The 116 injectors seem to be the common replacement from back when people knew how to work on these engines. There must be a list or document out there that the mechanics had. FastWoman said that she had a set on 1975 car in the past, and I've seen them on several salvage yard cars. I actually picked up a full set from a salvage yard from a ZX. They worked great for about a year until one sprung a leak at the pintle. I'm 99% sure that 105 - 116 are the same injector except for hose length, based on the flow data that's out on the interweb. I keep my eyes open so that I can get one more to replace the leaker. They're used on VW Super Beetles with fuel injection, a few old Volvos, some BMW's and some Fiats. In case my experiment with 90's era injectors doesn't work.

0 280 150 116 is the Bosch part number. I ran a set of those for a while. They seem to be the design that Nissan modeled their injectors on. They have a more vaporous injection pattern than the Nissan injectors, not that it seems to matter to performance. In your third picture isn't that an A46 - 00? I've not seen any over here that have JECS molded in to them, although I have seen a few ECU's and AFM's with JECS labels. I think that Nippon Denso was making most of these kinds of products for everybody in Japan back in the 70's. I've wondered if the JECS label goes on replacement parts or factory production parts.

If you blow up the injector picture you'll see the typical A46(I think) - 00000 number of the stock Nippon Denso or Denso injectors. They look like they were probably green when new. Pretty dirty now. Those are the older style two part insulators, with the aluminum upper half. Hard to tell if they are better or worse for heat absorption. There's an air gap in the middle which might let them transfer heat faster, but the metal piece might hold more heat. Nissan might have changed just because it's cheaper to make a one piece plastic insulator than a two-piece. And that 35 psi constant is an unknown. Kind of odd, as EuroDat noted. To hr369 - I picked up a ZX manifold, more just to have a complete ZX engine package than for the heat-soak problem, but have realized that you need a longer head pipe to fit the shorter manifold. You'd have to do some exhaust work, it won't swap straight in. Back to Post #37 though, I'm not sure that's the typical heat-soak problem. It doesn't usually wipe out all of the injectors, just a few. The engine starts but runs bad. Yours didn't start all. That seems more electronic or electrical. Then when it did start you said it ran rough for a moment. Heat-soak running seems like eternity although it's only 20-30 seconds. But, if you do have it, it will come back, and you'll get familiar.

How are you checking? Is there software available that checks, or a web site? Found some bewares on resetting passwords. Pitfalls everywhere. Here's one. http://www.tomsguide.com/us/heartbleed-password-phishing-scam,news-18595.html

Playing with the vane at idle only changes idle fuel mix. There's a screw adjustment on the side of the AFM to adjust idle mixture. It's described in the FSM. Have you checked coolant temperature sensor resistance at the ECU plug yet? That needs to be right before messing with the AFM. There's a chart in the FSM, Engine Fuel chapter, that will tell you if the ECU is seeing what it needs to see. Check at the ECU, if it's wrong then check at the sensor. If it's wrong at the ECU but right at the sensor, check the wiring in-between. Best to get each individual item correct before modifying any. They all interact, and the ECU expects them all to be right.

Sounds like dirty battery terminals. I almost bought a new starter for the same symptoms until I remembered to check. It's a common problem, probably more so on the Z's with their poor battery location. On that topic - I've found that those cheap plastic terminal covers that you see at the auto parts stores really do an excellent job of keeping the terminals clean. There must be a lot of water and dust that land on them when they're left uncovered. Mine used to get dirty within few months, now I haven't touched them in many.

Post up the ad, maybe someone here will think it's worth $1200. We can start a bidding battle. If that thought makes you nervous, then it's worth $1200.

If you didn't take it completely apart then whatever clogged it in the first place might have floated back to where it was. Start a new thread title "Rebuilding stock 280Zx pump" or something like that. Or PM Captain Obvious. He just created a whole thread about rebuilding pumps. Eurodat has rebuilt his pump also. Post a link to your thread in the thread linked below. We love to talk about fuel pumps. http://www.classiczcars.com/forums/fuel-injection-s30/51862-fuel-pump-check-valve-alternatives.html

Nissan didn't really intend the gauge to be accurate. That's why they only put two numbers on it, with a tiny red stripe at the end, and a note in the FSM or Owner's Manual that says if it touches the red, that's bad. Note also, that Nissan did not supply a temperature versus resistance chart for the sender, like they did for the coolant EFI sensor. It's just a step above a warning light. It might even change accuracy with oil pressure since they share the same power source.

Things aren't fitting. You said that out of the car it pumps. Do you mean that you had a hose to the intake in a tank of fuel and a hose from the outlet returning it, and you saw fuel flowing out of the return hose? And, how much gas did you get when " I even sucked on the exit side and got gas"? A big mouthful or just a taste? There is a check valve in the outlet side of the pump. Maybe it's stuck or something broke inside the pump and is jamming the outlet. Also, is it possible that you connected hoses backward? And is this a factory stock pump or aftermarket? How far apart is as far as you can? I took an aftermarket pump apart down to the steel rollers that do the pumping. Hard to tell what's really going on. How about a picture so we can see what you're working with.

"Acoustic resonance" seems like a mis-leading term. You have a mechanical vibration, that is noisy, I think. A noise above 70 mph wouldn't be scary, unless it sounded like a ghost. A physical vibration that gets worse above 70 mph, that might be scary. On the constructive side - It could be that your rear diff angle is off. With the RT mount, and the mustache bar issue, and use of the stock diff mount (is it new or old? Might need new), maybe you just have a misalignment between transmission and diff. Your description of wind-related implies a throbbing low-frequency noise, which implies something with some mass. Driveshaft seems to fit.