Zed Head

Your problem sounds more like leaking injectors. They do that when they get old. The typical hot start scenario is not a starting issue but a rough-running problem after it starts. The engine starts right up but runs really rough. Fouled plugs and no-starts are typical of too much fuel getting in to the cylinders. You might just need new injectors. Fingering the AFM at idle tells you what the engine wants at idle. There's an adjustment screw on the AFM for idle air adjustments. Adjusting the spring changes fuel enrichment over the whole air flow range.

I get the feeling that you're not a motor-head. Does the engine turn over? Is the electrical system intact (do the headlights work)? You haven't given any info on what you've tried so far, to diagnose the problem.

I only added the "smart" part to give some sense of how it's not as simple as it seems. I hope you come up with something. One way to add fuel everywhere would be the cold start injector. Then it would be a hot start injector instead. Dual function.

Just an observation - the AFM pictured in UFL's Post#6 is A31 624 000. EuroDat added a picture of an A31 625 000 in Post #12.

Something to think about on the hot start issue - it might not be that all of the injectors run lean, it might just be a one or two. I have the potentimoeter on my coolant temp. circuit installed for this specific reason and I can not get the engine to run smoothly by adding more fuel. If the coolant sensor was just overheated, the pot. should work. It seems more like a few injectors just refuse to behave. Not to destroy anyone's dreams. I've found some more modern style injectors that might offer a clue. I'm building a fuel rail so that I can install them and do some experiments. But many smart people have tried to solve this problem and none have solved it simply. Most solutions revolve around removing heat from the engine bay, or running a colder engine. Running at a higher fuel pressure would be worth a look,which you can do with the HF. It could be one reason the automakers went to 45 psi or higher. Views tend to be that they did it for emissions, but you can get a super fine mist of fuel with 36 psi, so that doesn't fully fit.

I was going to reply but I have EFI and you're running a carb fuel system. 5/16" (8mm) is right for the EFI system also.

The standard timing setting for the 1975 engine, warm, was 7 degrees. Many people bump it up for a little better overall engine performance but it should still run fine at 7. There's the ignition module possibility. They tend to show signs of failure at high RPM. Could just be coincidental that it happened near the time you adjusted the valves. You probably went out and ran up the RPM to see how things were working and might have pushed it over the edge. Usually the tachometer gets goofy also when the module goes bad though. The modules tend to fix themselves when they cool down, then go bad again when they get warm. Makes them hard to diagnose.

7-12 miles might be something has come loose. Kind of sounds like a vaccum leak, with the high idle, the backfire and the lack of power at high RPM (fuel mix off). Maybe check all potential leak spots, like the PCV hose from the valve cover, and the valve cover gasket, etc. Check for hose splits also, the old hoses get brittle.

How soon after the valve adjustment did the problem happen? If it was immediate, then it was probably something you moved when you took the valve cover off, or you didn't get the adjustment right. As for the throttle hang, that doesn't sound like BCDD if it goes away with a tap on the throttle. More like you got a plug wire stuck in the linkage, or broke the return spring, or something. Next time it hangs, leave it idling high, open the hood and see what's stuck. You've kind of taken a shotgun approach to possible causes, with BCDD and timing. If it ran good before, then a before and after focus might be better. Look at what you touched during the valve adjustment process.

Might be stuck on the dowels, or even paint on the dust shield, or paint on the dowels. Maybe spray some PB Blaster or Liquid Wrench in the holes and around the interface. If there's any gap opening up at all anywhere you could stick a plastic wedge in it, or piece of wood (something soft), to get the leverage to work on the other areas. You might have to move it a fraction of a mm at a time. If you're handy you might also be able to work up a pulling device, from a gear-puller, to stick in a bolt hole and pull on the edge of the transmission. But that might also break the housing, so it's risky. A dead-blow hammer has a similar risk. A sledge tapping a piece of wood might shock it free. Same breakage risk, don't hit too hard.

If you're really lucky, your cam survived and you can just fix the spray bar, or get another one. If you need to change cams, and get a used one, get the rocker arms also, and keep each rocker arm with the cam lobe that it was riding on. The cams are notorious for destroying themselves if things aren't just right after they're been moved around. Sometimes they still self-destruct.

Water is a product of petroleum combustion. It's normal. Normally it would stay in vapor phase but your cold exhaust system is causing it to condense to liquid, and drip out the tail pipe.

So it does adjust, but runs out of extension? Did you replace the shoes also? Maybe you got the wrong ones. I think that the later Z's, with the two piston cylinder (1978 and on), use different shoes than the early Z's.

superlens logic looks right on the need to rescale the vane movement for a wider range of air flow. It may be that instead of, or in addition to, a stiffer spring, they also went to a bigger bore. Less vane movement for more CFM. On people using turbo AFM's in NA cars, I think that what they're doing is using the turbo AFM body and swapping in the NA AFM "guts" or circuit board. On the theory that the AFM is an air flow restriction. There are few threads out there on swapping AFM internals. The end result is probably a mixed up AFM, with different vane action on NA ECU electronics. One more wrinkle - the turbo system, ECU and AFM, is designed for 265 cc injectors, the NA for 188 cc. Three variables; ECU, AFM and injectors. Just looks messy to deal with and the odds of success are low.

That looks like a 280ZX distributor on the engine now, with an E12-XX module (XX = 80 or 92). Pretty common self-contained module and distributor swap. The old one in your hand might be a 240Z points (I haven't seen one up close myself), or 280Z electronic distributor. Take the cap off and look. Maybe it's the one the car came with. On the leaning - it could be the fuel pump, the filter, the pickup tube in the tank... With a gauge you could check pressure before the filter and after and test the pump off of the car. Without a gauge it's hit or miss. There's not much to see inside the AFM. Most say it's best not to mess with it.

Do you have two sets of adjusters or are you describing one set? If the parts are fused you wouldn't be able to turn the wheel because of the slot on the brake shoe. If you can turn the wheel but nothing happens it would be because the threads are not engaged, either because they're fully extended or they have stripped internally. A picture might help.

There are probably millions or billions of other cars that aren't affected by heavy key rings. That's how the problem would be defined, probably the same in a court of law. Cars are so common that there are a defined set of expectations. Apparently, these cars don't behave as expected. Now if they put a warning label on the dashboard and people ignore it then they could claim consumer fault. If they knew people with heavy key rings had problems and did nothing then it's the producer's fault.

Download the 1976 FSM, open the Engine Fuel chapter and make sure that your TPS is adjusted correctly. The TPS is famous for acting like a rev limiter when it gets wet. Out of adjustment may have the same effect. Datsun Service Manuals - NICOclub Take your resistance measurements from the connector at the ECU. Download the EFI Handbook to get the pin numbers. www.xenons30.com/reference And it would be much, much easier to take a fuel pressure measurement than to drop the tank. Post a picture of the distributor. The 1983 turbo distributor only works with the 1983 ECCS, I believe. It's optical, not VR. Are you sure that the ECU you took a picture of is the one that the engine is actually using? It's possible that the PO wired in the 83 ECCS but mounted it somewhere else. Follow some wires to be sure.

But your 625-000 AFM number is designated for NA. The 624-600 number is for turbo. Motorsport! Air Flow Meter, 75-83 Z/ZX Non Turbo - The Z Store! Nissan-Datsun 240Z-260Z-280Z-280ZX-300ZX(Z31/Z32)-350Z-370Z Parts Motorsport! Air Flow Meter, 81-83 280ZX Turbo - The Z Store! Nissan-Datsun 240Z-260Z-280Z-280ZX-300ZX(Z31/Z32)-350Z-370Z Parts So what would the difference be then between the turbo/ECCS and NA AFM's? Maybe it's the ECCS system versus the NA's EFI ECU. Different computers, different voltages, different internal resistances? I don't know, but Nissan had two different AFM's used for the ECCS and NA EFI systems. The AFM is on the low pressure side of the intake tract so it shouldn't be a pressure issue. Just saying, Nissan used different AFM's for the same model year. The reason is unclear. Maybe superlen will figure something out.

That AFM and ECU is a matched set, they're designed to work together. Since you've discovered all of this strangeness though, you might take some time and put a full plan of action together. Obviously you know how to get around the interweb and are finding lots of information, and know what to do with it. But you have a collection of odd parts and could take many different paths from here. You could get the wiring harness, distributor and ECU from a turbocharged engine and have a very powerful turbo L28 240Z. Get the NA head for your dished piston short-block, and an NA AFM (if needed, still unknown), and NA exhaust and have a standard L28 NA EFI engine. Get the NA AFM and headers and have a low compression ratio L28 (which might sill be as powerful as the original L24). Put carbs on it. Or tweak and tune what you have to make it work. But there are still questions. It's been assumed that you have a dished piston turbo motor, but maybe the PO just put the P90A turbo head on an NA L28 block. Look down below the motor mount on the driver's side and make sure it says F54. Then pull a spark plug or two and locate a piston that's at the top of its stroke. With a good light you may be able to see if it's flat or dished. Did you get any extra parts with it? The turbo engines use a special distributor so the ECU (also special) can control timing. Could help determine your path or make sourcing parts cheaper. Barter for parts.

I would think that a timing light and some time would shed some light on the problem.

That's a turbo AFM. Here's a link showing the part number - Motorsport! Air Flow Meter, 81-83 280ZX Turbo - The Z Store! Nissan-Datsun 240Z-260Z-280Z-280ZX-300ZX(Z31/Z32)-350Z-370Z Parts I don't know that it will work right with the NA ECU. Nissan changed the way the AFM's are wired with the ZX's. Look in the Engine Fuel chapters of a 280Z FSM vs. a 280ZX FSM and you'll see (1976 versus 1982 for example). The NA AFM uses 4 wires for the potentiometer, the ZX only has 3. But the 4th wire might just be the altitude switch circuit in the NA system (discussed in other threads). Anyway, it's unclear that the turbo AFM will work right for you. You might want to get an NA AFM. Those injectors look like aftermarket. They have numbers on them that will tell you what they are. Probably NA since I don't think the turbo injectors are available aftermarket.

Made in America too. No guarantees of quality anywhere. SATURN Ion Sedan models Just saying, it always comes down to someone's decision. Usually some executive whose bonus is tied to short-term profits. There's probably a spreadsheet somewhere at GM showing how much each death or injury will cost the company versus the cost of fixing the problem(s). Like Ford and their Pinto.

The gear assembly should be just deep enough that the metal lock-plate fits in to the slot. It's piece #63, in the upper right corner of this drawing. The slot should determine how deep the assembly sits. Notice piece #65 also. It's the drive gear inside the transmission. I think that it might be plastic also and can get damaged. Datsun 280Z Transmission Gears, Speedometer Pinion (5 Speed-FS5W71B) (From Aug.-'76)

The ECU has already determined your wiring harness. You'll want the up-to 1976 square port headers, the engine bolt patterns and spacings are all the same, it's the body style that was different with the ZX's P90 head. Might be cheaper, easier and quieter to get a square port 280Z exhaust manifold. With your low compression ratio engine, in stock form, the header won't really add any performance. Apparently the stock manifolds flow pretty well. And where is the AFM now? There aren't many non-stock places for it to be. One problem you might find is that the PO left the turbo injectors in the engine. They will cause it to run rich, with the 280Z ECU, becuase they flow much more fuel thanthe NA injectors. They're a dark purple-brown color, whereas the NA injectors are a light-green or tan color. Somebody out there would probably trade a complete 240Z or 280Z engine, or two, for that turbo engine. Maybe even for just the turbo and turbo exhaust manifold. They're popular items.