Zed Head

"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.

When you say no fuel pumps, do you mean at the filter or rail area, or where you were able to get fuel to come out? Are you testing flow with the pump spinning at the same spot you're testing flow with suction? There's a damper in between the pump and filter, back where the pump mounts. Maybe that's the real problem. Or a clogged fuel line. If you pulled fuel through the pump with vacuum, but nothing comes out when the pump spins, it sounds like the pumping mechanism is restuck. Did you take the pump apart to fix it or fix it from the outside? If the pump motor runs, fuel should pump. There are no externally-controlled valves inside.

Was the engine fully warmed up? Like nice and hot? The thermostat does not open completely until the coolant is hot, so the coolant may be hotter in the housing than in the top-center of the radiator. Also, make sure the meat thermometer is calibrated.

Did you fill the tank, or just put in a gallon or two? Also, the pumps will spin backward if wired backward.

They can only be used with a combination of the F54 block and a later model ZX transmission. The bolt holes don't exist in the N42 block and early transmissions.

Walter Moore's chart would be handy here (attached it below). Yes, it would be 12 crankshaft degrees centrifugal advance. Not a bunch. 12 + 17 = 29 at WOT, factory spec. 12 +10 + 22 at WOT, current setting. Between 22 and 33 (add in the 11 vacuum) above 2000 RPM, depending on intake vacuum, current setting. Notice how they changed things for the 260Z engines. Kind of interesting. Maybe CR-related? http://www.classiczcars.com/forums/electrical-s30/34192-280zx-distributor-advance-curve-reference.html The post-WOT behavior implies some sort of heat soak problem. Fuel, carbs, coil, etc.

Bad gas? Might be worth the time to drain and refill. I posted this elsewhere, but the ethanol-blending requirements are averages over certain time periods, you can get high and low within weeks, and, also as noted by others, ethanol tends to draw water to the fuel. Today's engine systems compensate for fuel quality and blend, probably leading to a lowering/widening of quality standards for fuel. Our engines were designed for tight formulations. Fuel age is a factor also. I know someone with a sail boat whose carbs couldn't handle 1 1/2 year old automotive fuel. This was with a new 10 hp outboard engine. Had to have the carbs serviced and get new fuel to get back to right.

If it's a stock engine you'll probably find that there's not much happening with the L28 above 5500 RPM anyway. Lots of noise but not acceleration.

I might set dwell on the points first. It's commonly overlooked, with the assumption that point gap will set the dwell, but using a dwell meter is more precise. Dwell will determine how strong the spark is at high RPM. Too short and you'll get a weak spark.

I asked because I think that there is a thought out there that pumps need priming. It might even say so in the FSM or Owner's Manual. It may be that the factory pumps do need priming, but the aftermarket pumps seem to fill just fine. I don't know why the factory pump wouldn't also since with a full tank they should fill by gravity. Anyway, I would bet that if you just re-install everything it will pump right away, with a fairly full fuel tank.

Are you trying to prime the pump because you think that you have to or because it's connected and won't pull any fuel? I've run out of gas before and not had to prime the pump. If you're trying to pull fuel from below the level of the pump though, then sometimes you can just raise the can up a little to get it started, then set it back down to let it pump. Don't swap Mityvac with vacuum cleaner or shop vac. Fumes through an electric motor might create a flame thrower, if you're lucky, worse if you're not.

No editing allowed, so here's another post. A picture of the guts. You might also check the wires at the AFM sensor haven't rubbed through their insulation, causing a short. A piece of heat shrink, or tape or some glue might solve it.

I accidentally ripped apart a coolant temperature sensor trying to get the plug off. It came right out of the top with the EV1 connector attached, just minus the threaded metal portion. The actual sensor is just a blob of semiconductor on two pieces of wire, surrounded by a gel, probably silicone, inserted in to the brass housing. If you have an old coolant sensor it might be worth an experiment. I'm sure it would have a fast response time out of its housing.

I think that Fast Woman may be right and you have weak pump volume. But I wonder if the volume is low because you're pulling air in to the pump. There's enough gasoline getting in to keep a seal in the pump mechanism and let the pump work but it's pushing mostly air instead of fuel. Or the fuel is sitting at the bottom of the system, back-flowing in to the pump to let it hold pressure. Maybe. Check your fittings in to the pump and the filter and its fittings. Or a quick test would be to disconnect the inlet hose to the pump and run a hose without a filter to a gas can. Make sure the hoses seal tightly.

Check your cam lobes (a flat one will cause an intake backfire - check lubrication while you're in there), valve lash (a loose one is like a flat cam lobe), and fuel pressure (lean mixture cause backfires). Those things are always good to do in general.

It may be that the things you listed are not all related. Following FastWoman's logic, what happens if you just let the pump run alone for the same amount of time it would take the engine to die, but without the engine running. Is the behavior the same? That would separate any engine heat, injection issues from the general weirdness. Just let it run, it won't hurt it, that's what it does when you're driving. And are you running a stock fuel rail and return line?

There are a few threads from the past about the solid state MSA regulators. They were kind of sensitive, apparently, and failed quickly. Hate to say bad things about a sponsor's product, but not all of their products can be perfect. Your signs point to a bad regulator.

A backyard check valve solution might be to gut a broken pump with a good valve and place the pump body in-line between the working pump and the filter. Or take the check valve and find the fittings to fit a hose barb and just insert it in-line. I have an old check valve and pondered using it with my aftermarket FPR that leaks down but the pressure was on the wrong side to use it that way. Just some options, if you have a pump that works well and is installed. If you insert the valve low in the fuel system, the leaky part of the fuel system should stay full from gravity.

Did you leave a comma and a word out? "tapped quickly against an exposed terminal from the centre post of coil" You want the center terminal to be close to ground so that it can spark. About a spark plug gap's width away. You could also put an old spark plug in the center wire and place it's electrode to ground. That's where the spark will happen. Then tap the jumper from negative directly to ground, away from where your center terminal is set up. You'll get a small spark from the negative jumper and a bigger one from the center terminal. The next step, or it could be the first, would be to disconnect the negative side of the coil from the ignition system. Have only the jumper wire connected, then do the tapping. If your ignition module is shorted out, it won't let the coil circuit be broken, so there won't be a spark. I have to warn though, that damage could happen when messing with sparks and electricity. I don't want to take you down a bad path, where you fry your ignition module while testing it. Thinking about your problem, I remembered the Pertronix module can be damaged if the key is left On without the engine running. It may be what happened to yours, and it could happen while you're testing. I would stop and reconsider. The things that I do may not be suitable for general consumption. http://www.pertronix.com/support/tips/ Here's another link from Summit racing. It's for the Ignitor II but it mentions look for signs of overheating on the module. http://static.summitracing.com/global/images/instructions/pnx%20ignitor%20ii%20tests.pdf

I had a GM HEI module that started generating tiny weak sparks that wouldn't start the engine after I forgot to put two spark plug wires on before starting, after doing some work. It was hard to decide it was bad because the spark was there, just weak, but I had a spare module and know that electronics don't like stray electricity. Installed the new module, no other changes, and was back in business. You can test the coil using a jumper wire on the negative terminal. Set the main coil wire up at a good spark distance. Connect a wire to the coil negative, turn the key on, then tap and remove the wire to ground quickly. Each tap should generate a strong spark. You'll be mimicking what the module does. Odd aside - when you add "ing" to mimic, you also add a "k". Weird.

It's good to have a plan.The F54 is just an engine block. Here's a calculator that someone created that's really handy for seeing how different combinations of parts work together. OZDAT.com Engine Design Utility

EuroDat's talking about the fourth picture down in your first post. Take the lower left valve/switch out, the plastic one, it's not used on your system, and replace it with the new coolant sensor (if the threads are correct, they might not be). Your engine should not really be driveable at all without that sensor. The fact that it is means that it will probably run worse when you install it. Other things have probably been messed with to get it to run. One of those two plugs in your hand in Post #4 is probably the coolant sensor plug. It's supposed to be connected to the sensor. It's critical to proper operation. You have some work ahead of you. Those new parts will probably not do the whole trick but they'll get you closer.

No offense but you haven't even described your starting point. Swap from what, in to what?

Are you running points or Pertronix ignition?

What is the resistance on the coil? The 1972 points coils had a resistance of 1.5 to 1.7. Looks like the resistor is 1.6 ohms, as you saw. So total resistance on the primary circuit would be 3.1 to 3.3 ohms. Maybe you have a low resistance coil and you need more resistance. Or a different coil. Sorry, I might be confusing things. It's better to give too many facts rather than one at a time. If everything is right in the ignition system, it might just be bad tachometer. Has the tachometer ever worked correctly?