Zed Head

Any chance you could take a picture of your fuel system and post it? The top of the engine. Still not getting a full picture of when things happened and which of the things you did were to fix a problem or just coincidental. It sounds like your FPR might be be dead but a plumbing error is possible also.

It's easy to get spun around when trying to figure out the EFI systems. Just to be clear, when you're doing these isolation or deletion tests, taking out the filter or the damper, is the FPR still at the end of the system? You should be able to get more pressure by clamping the return line tightly. You said that you had this problem with your old pump. You actually measured pressure and it only went in to the 20's? Like you're seeing now? It might be that your FPR is no good, and the pumps are fine. Give a good description of one of your tests, from fuel pump, through the lines and any devices, and back to whatever container the return line goes to. There's not a good clear picture of what's happening. What kind of FPR are you using? Most people get an adjustable FPR with the Pallnet fuel rails.

Sounds like the AAR is not working correctly. That would explain the low cold idle and fast hot idle. Don't put the AAR in hot water, it's an electrical device, it has a heater inside. Connect 12 volts across the two pins. It should close completely within a couple of minutes. It should be about half open when cold. The rich when driving problem could just be exhaust fumes leaking in through the hatch. A common problem.

There's a filter sock inside the tank on the outlet port. Yours might be plugged. Might explain why both pumps showed low pressure. That pump looks right for the car. High pressure EFI pump.

That's no good. Where is your gauge? What brand of pump? Sounds like the inlet to the pump might be clogged. Is the pump noisy when it's running? That's a sign. You should have still seen 24 psi at the rail without clamping the return line. The FPR doesn't open until 36 psi is reached. It might take a while to get there with a weak pump though, pushing through the filters. Forgot to say earlier, congratulations on getting back to health. Don't know what ruins a liver but it sounds serious.

I didn't read your first post right. Are you sure that it's not an injection problem, instead of pressure? Not clear if you actually measured pressure. Of course, the cold start valve should get it started even without injection if there was pressure. Don't overlook that the DC fuel pumps will run backward. Spinning, but no pumping.

I think that you might have got too ingenious for your own good, if you shorted the oil pressure switch to ground. You want to just disconnect the switch, leave it hanging. Then the pump should run when the key is on. Sounds like you're getting a Start because the relay bypasses the switch at Start. Then when it starts and you let the key back to Run, it kicks off, like it's supposed to. You could probably just put the oil pressure plug back on and the engine will start and run fine. Just a guess. If you do have the plug off, for the "bypass", check that it's not shorted internally. The relay kicks open when there's a ground at the switch.

How much?

You could try starting fluid. It should start, run for a second or two, then die if the timing is right and you have good spark.

Should have mentioned also that it might be that today's new aftermarket regulators are just calibrated to 40 psi, or have a wide spec. range. Quality control in the aftermarket is poor. Bosch does not mean what it used to either. If it runs well at 40 psi, passes emission, doesn't foul plugs, etc. consider just using it like that.

Hard to say why you're having such a problem with this. You are having waaaaaayyy more difficulty with getting fuel pressure down to about 37 psi than almost anybody in the history of the forum. Kind of exaggerating but need to be clear that you should not be experiencing this problem at all. Because it's so unusual it wouldn't be a surprise if you had similar problems with an adjustable FPR. Even though it's adjustable. Can't emphasize enough that the FPR is just a spring-controlled check valve, in essence, when the vacuum source is removed. It's super simple. It might be that somehow you're adding complexity somewhere, or somebody else did before you got the car. Have you examined the fuel system return lines all the way back the tank? I had considered adding a second FPR to my car for a short while because I had a pressure leak-down problem and didn't have the correct FPR to fix it right. I never did, it was just a thought, but maybe somebody has inserted a second regulator or even a spring-loaded check valve, to hold pressure. You might actually be fighting a PO's previous "fix". If so, you'll have the same problem with any regulator.

Does it smell like good clean gasoline, or turpentine? That's what I was wondering. If it squirted then fuel is in the intake manifold. Why isn't it lighting up, is the question. I don't think the "life delayed me" wordage is allowed unless it's over a few months.

That could be twenty years. I would see what's in the cold start valve line. Looks like the electrical checks out. The same fuel is probably in the injectors since they are branches off of the fuel rail loop. The new fuel will pass by those branches but there's no driving force to replace it besides the few squirts while trying to start.

But, of course, the history of the engine might be most important. If the cylinders are dry they might not generate enough compression to fire a gasoline mixture. Squirting oil in to the cylinders can help that. Maybe the car was parked because it quit running. You haven't given any history or much about how you prepared the engine to start. You might be about to suck a bunch of old crud and fuel in to the cylinders. The best is assumed, but maybe you should stop and rethink.

Many different ways to get the engine to run. Like many you've said that you "ran the tests" but didn't list them out with results. Here are a few things that you could do just to learn more. - Let the pump run for a while. this will flush old fule out and get new fuel close to the injectors. Of course, if you have water or old gas in your lines it will also contaminate your new fuel. - Remove the cold start valve and run the pump. Or just remove it and place the nozzle in to a container and give it power. See what comes out. It might be old dead gasoline. - Test the injectors using a "noid" light or one of the various test methods described in the forum. Make sure that the injectors are getting the proper circuit to open and close. - Use a screwdriver or stethoscope on the injector bodies to see if they click when the engine is turning over, like they are supposed to. - Connect a jumper wire to the coil's negative post and tap it to ground with the key at Run. Every third tap should cause all of the injectors to click. This might be the quickest, easiest way to confirm the injector operation. It's quiet and it's a one-man operation, in the engine bay. If the injectors aren't clicking they're not opening, if they're not opening there's no fuel. - Use starting fluid in the intake manifold to make sure the engine will actually run with fuel.

The answer to the problem is probably here - http://www.atlanticz.ca/zclub/techtips/alternatorswap/index.html

You should download the FSM from the Downloads section of the forum. Read the Engine Fuel chapter. The fuel pump does not prime on the 280Z, or turn on with the key. It only gets power during Start or engine running. Thinking that the pump should get power when the key is on is a common 280Z error. The Engine Fuel chapter has an extensive list of tests that you can run. Many things have to be right for the engine to start and run. It might be that you have fuel pressure but no injection. Or that you have fuel pressure but the fuel lines are full of water. Or bad gas. Lots of ways to test these things. Welcome and good luck. https://www.classiczcars.com/files/category/13-280z/

I'm just playing around jakay. I love a good logic debate. Words and what they mean. I Google a lot. Good luck. Too bad you couldn't have made it down to the ZCON in Atlanta. The car probably would have been a hit down there.

Is your Z really the "26th" Z? I used the serial number to designate the lineage of somebody's Z, like you're doing with your screen name, and HS30 tried to correct me. Should we go down the rabbit hole? Should you change your screen name to be correct?

The operation of the pump and its relays is described in great detail in the FSM. There's a flaw in the design that lets you test the pump and relays, by pulling the oil pressure sender plug off and turning the key to Run. The pump should run then. Why do you think that you have a problem, besides the 3.4 volt measurement? Not sure that your understanding of the wiring is 100% correct.

No need to pick any side really. Just wanted to give you a heads up. Conversations can take a turn for the worse when these early cars come up. Some people like the full restore, others like some original history. And, there are others who would love that car for a V8 conversion, because it's so clean and rust-free.

HS30 loves to split hairs and other things. Serious. Don't get caught up. He has an early Z and is incredibly protective of the brand and model. There are a few other guys that might join in also. A tiny club of early Z owners. You might have to pick a side. What are your plans for the car?

I had an internally regulated alternator/regulator fail once and the dash light came on dimly and got brighter with RPM. But the voltage looked correct on the meter. The internally regulated alternators use solid state regulators though and they can fail indifferent ways. Here's the FSM description for the external, mechanical, regulator. There are test procedures in the FSM. There's even an adjustment procedure. Kind of a shame that we all swap to the later models when it's all there in the FSM's.

The light tells you when it's not charging, too little. The needle tells you when it's too much. It's kind of primitive compared to today's electronic monitoring systems. Are you sure that it failed? Could be that the voltage sensing circuit lost contact. It's not clear what you mean about the VR. You said the old one is there, then said it's bypassed. Not sure what you mean. Did you convert to an internally regulated system?

Pretty cool. I feel like I just bought a brand new 240Z.