Zed Head

Lock to lock could be separate from ratio, maybe. Not sure exactly where the stops are but aren't they on the hubs? 280Z hubs different from 240Z. Different knuckles. Shouldn't we just measure the ratio? Not sure how to make that a one man operation.

I just did my 76 and got 3.1 Surprisingly easy on a cold dry smooth garage floor. I need new tires.

The FMS's kind of blend the lock-to-lock and the ratios together. This is 1976 and 1977, above, 76 above, 77 below. Hard to tell what's what.

I don't know if this will help or not but the graphic is pretty exciting. Safe for work. https://www.hagerty.com/articles-videos/articles/2018/09/20/datsun-240z-values-show-appreciation

What was the price before? There's no info about the running gear. Engine condition, automatic transmission, etc. Probably fine, but still, nothing there. Looks nice. But y'all are pretty far away from most of us. Might help if there were shipping options.

Could be. Back pressure can make a difference, for sure. If a new pump doesn't fix it, at least you'll have a spare pump. Always good to have spares. I asked about pump position because sometimes people put the pumps in the engine bay. That creates a long path to suck on for the pump. The electric rotary pumps like to have the inlets supplied by gravity. They don't like to suck. I just saw that yours is back by the tank, so that's good. The pre-filter can cause problems also if it's too fine. Too hard to pull. The mechanical cam eccentric actuated pumps have been used for years. That pump alone should supply what the carbs need. Are you getting side-tracked, maybe? You might go all the way back to 1971, remove the pre-filters, use only the head-mounted pump, and a high-flow filter, or just the banjo-fitting screens. Sometimes we're overprotective. Probably fine for a test and might tell you something. Back to basics.

This has been bugging me but I think it's true. His parents will probably have to buy the car for him. Best option might be the "you won't have to drive me around anymore" or "I'll quit borrowing the family car" scenario to his parents to get the ball rolling. Plus it's right there, just roll it down the road. Just saying, basically, the neighbor might not have the patience, knowing that he's not talking to the actual buyer. The OP is basically a negotiator between the seller and the buyer. Identify and examine the concerns of both parties and have answers for all of them. Then get them together and see if you can make it happen.

Here's a thought that might stand alone - get another cross member and just do a swap. Faster, easier, doable without removing the engine. The car is only stuck in its spot for a short time.

The key is stabilizing things. Put the car body on stands with the suspension hanging. Otherwise when you lift the engine the car body will lift also. Support the engine at both front back and sides so that it can't tilt. If you get everything supported and stabilized you should be able to loosen the engine mounts and verify that it's stable before actually disconnecting it from the car body. A potential problem is getting everything ready for separation then finding that you do have to lift the engine for clearance. You should be able to visualize what needs to move though, before actually dropping the cross member. The big realization is that once you get the cross member out, you're stuck with the car and engine in that spot until you're done and it's back in. Of course, you'll want to be able to move the car around so all of this is probably moot. Think of the disaster it will be if the engine falls of of the rigged up mounts. Good luck.

8 implies a voltage drop due to current flow. There's power there. Might be that the solenoid piston is just stuck. Tap on it, maybe, when it's powered, and see if it comes unstuck. Injectors get stuck often and a tap will free them up. Same basic concept as those magnet valves. Welcome to the world of old crusty parts.

They do if you want them to pass vacuum. Looks like they're normally closed. You might double-check your hose connections too. Can't see what's connected to what in your picture.

Check if that first magnet valve is normally open or closed. Might be an electrical problem. Either way, if it's not open there's no vacuum supply. It's all right in front of you in the engine bay, the bottle, the hoses, and the magnet valves. Should be able to disconnect some hoses and see where the vacuum is not happening. Also possible that it's not making it through your selector valve. It's a pretty long path from the intake manifold to that mode door actuator. Or even that the vacuum actuator is holed and inoperable. Or that it's disconnected from the mode door. I think that it's a piece of wire that ties them together. Or a mouse built a nest in the ductwork. They love Z ductwork. Many possibilities. You found the right picture in the FSM. It's quite a system that Nissan put together.

You've probably lost vacuum at your vacuum tank. I had a hose that kept splitting at the tank's supply side. Cold air was the sign that it had split again. The mode door is vacuum operated. No vacuum, you're stuck in cold mode. You can see it in the illustration.

Yes, you should try to buy it.

What was the pressure before? And what is it supposed to be for your engine management system? Sorry, again, but there's no "yeah buts" that work. We've all made mistake in how we thought things worked. Best to absorb the new knowledge and move on. You can waste a lot of time trying to make wrong look right. Your statement has a lot of new wrong in it too. Seriously, it does. You might take a step back and ask yourself if the 1991 engine management system you're using is the most effective way to get what you want out of the engine. What you really need is the factory service manual for a car that used that engine. Looks like the Toyota Supra used it. https://en.wikipedia.org/wiki/Toyota_Supra#A70 https://www.amazon.com/Service-service-electrical-diagrams-specifications/dp/B005DGOLW4 Might be more effective to just use Megasquirt.

It's more pleasing to the eye than this one, for sure.

Seriously, I've only surfed some heating oil stuff recently. Or is this welding gear?

I had this same type of problem on a lawnmower. I think the hose delaminated because I had been using starter fluid to start the mower and overspray got on the hose, swelling it. Still, same effect. It would start but lean out and die after a few minutes. Not obvious by eye. Don't forget that the inlet side of the pump is under suction.

Your free-flow test seems to show that the pump flows fine. 25 versus 30. 25gph is a lot of fuel. I don't think anyone here has an engine that could burn that much. If you do decide to get a new pump, I'm with jonbill on the brands. Get an OEM brand, without the hypey name. Most of the old brand names like Holley have been sold and the quality level minimized for profits. You're buying an expensive name on a cheap product. "Sniper"? What does that have to do with cars and fuel? Hype. I didn't read the whole thing either but where is the pump mounted? Was the flow test with it mounted in its normal spot? Position can affect performance.

The key finding is that they are even across all cylinders. Unless you plan to take the engine apart there's not much to gain by measuring again. It's just a number.

Good luck Fast Sarah. You know that it's okay to come back and share some knowledge even if you don't have a Z...

The numbers are so consistent that your test method seems fine. I think that "racing" cams can give lower cylinder pressures because the valves close later, to get more charge in to the cylinder. The gauge hardware can give lower numbers also. The tubular extension that makes it easier to reach the plug hole will give lower numbers for sure. Is it an L28 head or modified L24? You could have dished pistons under a head designed for flat-tops.

Sorry. Not right. It's just not what the O2 sensor produces and not how they're used by the ECU. https://www.autozone.com/repairinfo/common/repairInfoMain.jsp?targetPage=productsHowToInspect&leftNavPage=productsHowTo&pageId= 0996b43f80a01215&subtitle=test http://www.autodiagnosticsandpublishing.com/feature/o2-sensor-testing.html 91 is going to be the simple narrow band sensor. And, 91, just like all of the EFI control systems, needs all of its sensors intact, connected and working correctly. I doubt that it has a limp or fail-safe mode. The engine is just running poorly because the inputs to the system are bad, including ignition timing and fuel pressure probably/maybe. At least it runs though. Good luck.

Consider buying an OBD reader. It will tell you the codes that the computer is generating, which can come from feedback or just damaged components. Some OBD readers can also scan live data. With an app on your phone or a computer program and a USB cable, tou can see the senosr values, and how the computer is respnding. IT's a great diagnostic tool and very educational. I have the BAFX reader, and the Piston Android app. Many other options though. Not sure what year your engine harness is but it's probably OBD-II. https://www.amazon.com/BAFX-Products-Bluetooth-Diagnostic-Scanner/dp/B005NLQAHS

Good luck. They all produce a voltage. https://www.fixdapp.com/blog/oxygen-sensor