Dave WM

I am sure its been covered but seems like I could not find the exact procedure. I removed the self locking retaining rings (chisel break them out they came) but I can't seem to press the u joint far enough to get the cap to extend more that about 1/8" at most, not enough to grab and pull the cap off freeing the U joint. I may end up welding on to the cap so I can pull it off. I seems the internal structure of the U joint prevent sufficient clearance to push the cap out any further.

Are you trying to support 700 hp? If not I would be wondering if that much fuel having to be regulated back to the tank would stress out the FPRegulator. Did you say this is the second pump that is only producing 26psi? and that is with the return clamped off? You say you are sure its the pump but I don't remember you saying you tried feeding the pump as I mentioned to make sure its getting a free flowing supply. The pump is designed to push fuel not pull it thru a restriction.

Not excessive (compared to mine, which works fine) so now we know the power supply to the pump motor is not the problem. and the amp draw is ok, this would tend to say the motor is at least drawing the correct amount of power. Next did you ever try feeding the pump from a source other than the fuel tank? That would eliminate a fuel supply issue. I would just get a gas can and a long rubber fuel line, set the gas can up on a chair so its about the same as the fuel tank, and hook that up to the inlet of the pump.

that kind of thinking makes it hard to diagnose but its your car, go for it.

here it is

I get a 2.0v drop video to follow. I also checked by leaving the setup but rather than look for drop (pump + term compared to Batt + term) I connected from Pump + to chassis ground. got about 10v suppled to the pump. This is with the engine not running. Typical battery voltage with the alternator working would be close to 14v so a 2v drop would supply the pump with approx. 12v.

So just to be sure, you ran a wire all the way back to the pump and connected from the pump terminals and then compared to the battery post?

ok reading the amperage at the battery (start solenoid off, cold start injector unplugged) when switched to "start" to energize the pump was a fail, over 10 amps meter would not read, so no idea of what it should be. But if you want you can duplicate and at least confirm you are over 10 amps. Will try for a voltage drop at the pump later with my helper around.

that seems odd, I would have expected more of a drop than that. That pump has to pull a few amps easy, with all the wiring and relay I would expect a bit more. Not a lot but more than .02v. Are you sure you are getting a good fuel supply to the pump? . I am going to take a reading later today on my setup and see what I get. Maybe a current draw test would be a better idea. could do right at the battery. Pull the start solenoid, disable the cold start, ign to on, get a current reading, then to start get another reading. I will try that as well, give you something to compare to. Or I will just get a current reading right at the pump, that is better, but means having to disconnect one of the pump leads. You could always just buy the OE pump they are out there, expensive but that should eliminate the issue. think it you shop around you can get them for around 200$ I replaced my working setup just to take advantage of the built in pressure relief the OE pump has. But still the after market pumps should work. I too had one of those airtex and it worked fine.

Checking the resistance of the pump is not what I am talking about, its the resistance in all the wiring including the relay that supplies the pump with current. You need to check the voltage at the pump terminals while its running. Just make sure it does not drop too much (it will drop some compared to when the pump is disconnected, you just don't what a LARGE drop in voltage.

here I go in to detail about testing voltages

it will tell you if there is a high resistance in the pump electrical supply. I don't know how you took the 12v reading. If you did that with the pump disconnected, you gained little knowledge about the power supply viability. A high resistance in the circuit would still read 12v, put a pump load on it and it could drop a lot.

check the voltage at the pump under load. IIRC you have tried two pumps both give you the same result. I suspect the pump is not the issue, but do as you plan, if a 3rd pump give you the same results I would suggest re reading my prior post about eliminating variables.

You need to break it down. start by setting up the pump stand alone with just some tubing and buckets. Carefully setup some wiring (no sparks near the pump or gas) and see if you can get the pump to work. Do a flow volume test then a PSI dead head test. Once you are sure the pump is working try it again this time using the power supplied by the wire harness but still using buckets for feed and return. Next introduce one thing at a time, try hooking up the outlet to the car test the flow and volume. Next the supply from the tank Next the return to the tank ONE variable at a time. You have already tried stuff and not getting desired results. when that happens with out being there to see exactly what you are doing the above approach HAS to find the problem.

No need to freeze it, its not a cold weather valve, more like engine not warm valve. Back in the days of carb cars you would push the pedal to the floor then release, then start. Pushing the pedal to the floor was how the carb cars would set a catch on the butterfly valves and hold them partly open. This allowed the extra air (the choke provided the extra fuel) needed to start. The AAR does the same thing for FI just does not need you to press the pedal to set it.

check voltage at pump.

What Jeff said.

Does the pump run with the key in the start position? is the FPR installed?

there are so many ways to go about this. 1st is get the FSM and check the temp sensor AT THE CONNECTOR for the ECU. the AAR should be about 1/2 open IIRC but again the FSM should show this. You will need to check methodically to get it working right. The biggest problem trying to diagnose remotely is there always seems to be some critical piece of information not given that can cause chases down rabbit holes. The FSM is you best bet.

I am hoping for the 280z dash, last I saw they were looking for a NOS to compare to the prototype (think it was on Instagram).

based on the age of the box mine came in, I am presuming it was pretty old. I will look closer to see if I can find a date code. I have it as a spare, glad to know it does not leak. When I travel I carry with me a box 2 ECU's ign module fan belts voltage reg tire repair kit air compressor fuses/glass and links FSM pressure regulator fuel pump multimeter tools oil/coolant AAA card :) that's a partial list anyway, I should prob give it some more thought and just have a permanent travel box to take. I was thinking about adding a radiator but that takes up quite a bit of room. I do plan to make a cross country trip in the next year so want a pretty comprehensive break down kit with me. Maybe a good thread, "what to you take with you on long trips"

I think I have a video, but if you have a crack there will be a sharp point at the end of it, this is a stress riser or a concentration of stress, and will tend to continue to follow that point lengthening the crack. using a small moto tool, you can fit them with a bit that has a very small ball. at the very end of the crack if you simply use the ball to cut a round end to the crack, the stress will be less focused and should help to stop the crack from continuing. It does not have to be a large radius just enough to make in no longer a sharp point.

That horn button is made differently from the OE. iits harder (the OE has a dense foam that has some give to it, the 90$ is much harder, more like solid plastic). Its also much less likely to crack along the mount ring like the OE does, which is good. I would suggest you pop for a new mount (plastic part with the snap ring that bolts up to the steering wheel and is what the button mounts to) if your is even slightly compromised (crack) as the harder horn button will def impart a stronger clamping force and break a weak mount.

best birthday present I ever got, "bolt buster" induction heater. Expensive as heck but worth it after the hassle of a couple of hard to get at bolts get sheared off. Now I see China is getting in on the action https://www.banggood.com/900W-Rusty-Nut-Screw-Remover-Ductor-Magnetic-Induction-Heater-Kit-Automotive-Flameless-Heat-p-1336959.html?gmcCountry=US&currency=USD&createTmp=1&utm_source=googleshopping&utm_medium=cpc_elc&utm_content=frank&utm_campaign=pla-mix-us-pc-0626&gclid=Cj0KCQjwsMDeBRDMARIsAKrOP7F54ipCMtEAcUhjlNt-tpYl87Zh4oP721bngv-yv0LVuAnF7Gz2h3IaAvhdEALw_wcB&ID=48035&cur_warehouse=CN

have you considered routing a radius at the end of the cracks? just a tiny one but enough to relive the stress concentration? I had a single crack that I terminated with a tiny ball bit on a dermal, has not grown. I suspect it would have stopped it from growing as much as it did if it had been done when the crack 1st started.