NewZed

I'm just a rookie but the only thing that would "use" the RPM data would be the ECU. The CAS delivers that information, the ECU uses it. Seems like a map, or look-up table, issue in the ECU program, if it happens exactly at 3500 RPM no matter what (note that the stock tachometers are not super accurate, so 3500 may not be 3500). The map, programmed for the stock Z31 that the ECU came from, is doing something at 3500 RPM that your L28ET engine doesn't like. Maybe the ECU is expecting other information at 3500 RPM and it's not there. The ECU might be switching modes, and getting poor information from the sensors after 3500 RPM. Or it might be switching modes because it's getting unacceptable information from the sensors. For example, one mode that switches at 3000 RPM is the injection mode, from group injection to simultaneous. Another one is EGR at 2700 RPM. Another one is RPM limiting to 2000 RPM if the MAF signal is bad, which doesn't seem to be your problem. These numbers are from the 87 FSM. Of course, since you're getting a CAS code, it might just be that the CAS signal is consistently breaking up exactly at at 3500 RPM every time. They might be the same problem or two different ones. Just offering a different perspective. Helps me learn. Good luck.

Raising fuel pressure should have fixed a lean problem and possibly created a rich problem, assuming the same injector open times. The ECCS assumes a certain fuel pressure so it seems like that should have had an effect. It was just a guess. As for timing, I didn't think through how the Z31 ECCS system works. It would probably be worth some study though.

Raise the fuel pressure a psi or two and see if the problem goes away. You said it was lean at the problem point. What's your timing doing when you rev? Have you checked vacuum advance centrifugal timing advances to make sure they do what they're supposed to?

Connect the two hose ends from the solenoid valve or run a new, longer, single hose. Make sure to insulate any wire ends that might have power if you remove the solenoid.

The wiring of the ECU connection is not the same, so even if you swapped AFM's, you'd still need to swap EFI harnesses too.

Some of the popular brake swaps end up with the bleed bolt at a position other than the very top, where the air is. The bleeder needs to be where the air is, otherwise fluid flows past but doesn't take the air with it. You might have to remove a caliper mounting bolt to rotate the bleeder to the top for bleeding then put it back for use. Just something to check, I'm not familiar with the details of your swap.

Check bleed valve orientation.

Your biggest problem might be that you're not using a meter to confirm whether things are right or not. Looks like you're just connecting wire colors and looking at the TunerStudio screen, hoping things work. In the long run, you'll be way ahead if you get a decent multimeter and learn what it's for, and how to use it. A few continuity/resistance and voltage measurements and you might not even need this thread.

The fuel pump relay should be right above the handle for opening the hood, inside the cabin. It even looks like the drawing. Check to see if the original wires to power the fuel pump are still there by the pump. If so, it should be pretty easy to figure out if they can be re-connected. It may be also that everything is already connected correctly and you don't know how to cycle the pump power. Either disconnect the small wire at the starter solenoid and turn the key to Start, or turn the key to On/Run and rotate the AFM vane. Both of these actions should provide power to the pump. If you don't hear the pump it may not be a power problem, just a stuck pump. Use a meter to verify.

There's a switch in the AFM and a relay that would be used to get back to factory set-up. See the wiring diagrams and descriptions in the Engine Fuel, and Body Electrical, chapters - http://www.nicoclub.com/FSM/ Since you're asking about a "pressure switch" to control fuel pressure I'll say that you should read all of the Engine Fuel chapter, before you do any work on the engine and it's fuel management system. Things will make more sense with the basics in the back of your mind while you're working.

Everything that's used with your stock four speed will work with that five speed. That five speed is essentially identical to the four speed except for the fifth gear. You will lose the top gear switch though, that activates the solenoid for your vacuum advance. You can just bypass the solenoid to have vacuum advance in all gears. It's described in the Emissions chapter. If you replace any clutch parts, just make sure they have the same dimensions as what's on the engine now. Cheap parts that are easy to replace are the pilot bushing, and the front and rear seals on the transmission. If you're going to put a new clutch set in, you might as well do the rear main seal on the engine also, if you have the flywheel resurfaced. The super cheap swap would be to just move the shift lever over and re-use all of the old parts. You'll want to take some Scothbrite or similar to the main shaft to make sure the pilot bushing works right, and the clutch disc locates freely. Looks rusty. Don't forget to check the speedo gear. It will swap also.

Isn't the intercooler for NA drag-racing a bag of ice on the intake manifold? With the modern glass-filled nylon materials, you probably won't get the same effect but there are probably people cooling other parts of the intake ductwork.

Just forumizing. It's interesting to see how the path to "my engine doesn't run quite right" starts.

What did the valve control? In other words, what are you giving up with your simple "solution"?

Take a wheel in to a store. They'll probably let you test fit without buying. Make sure they don't stick out the back of the wheel or they won't clamp properly.

Isn't inline6 saying here that WPN-062 is the diesel pump? RockAuto is selling the -079. From the info link on Rockauto - More Information for AISIN WPN079 Alternate/OEM Part Number(s): 2101017S25, 2101017S26, 2101017S27, 2101017SY7, 21010V0725, 21010V0726, BA01017S27 Edit - maybe the WP079 is special after all. The other manufacturers all list the same part number for gas and diesel but the WPN079 doesn't show as a gas engine option. AISIN doesn't even have a gas engine option (1978 280Z example) Carry on and good luck...

I'm pretty sure that people use the early 280Z EFI tank in 240Z's when they switch to EFI because they want the internal baffles and the bigger fuel lines for the high-flow/pressure EFI fuel pump. Should work fine for a 260Z since it's in the middle. I'm just interpolating, no actual experience with a 260Z tank.

Why not just leave the electronic distributor and ignition module in? Why remove it for a points set-up then circle around to electronic again? It's already there.

It's kind of an unwritten principle on this forum that the type of work you listed is pretty much routine maintenance. On a Moderator's bad day you could probably get banned for even suggesting that you would pay someone to do any of that. It's all relatively easy, non-complicated work. All of it. Time and sweat required of course, but the only "specialized" tool you might need would be a spring compressor. Not kidding and not trying to run you down. It's all simple stuff.

Starting fine with the screwdriver in the electrical switch is a sign that all of the relays and wiring are correct and working, unless there's a heat related problem. Really sounds like the key just isn't turning the switch far enough. Take two pair of needle nose pliers, grab the metal piece with both, and twist the part in between. That way there's no load on the connection with the keyed mechanism. Visualize first to make sure you're twisting the right way to get more action from the key.

Are you sure they're 280Z springs? Are they progressive or straight rate? One coil is a lot. Look for numbers on them. 5022 is the 280Z number. If a coil was cut it would be obvious since the factory bends the final coil to fit the seat. They might be 280Z coils that someone cut to use in a 240Z. Documented on Hybtidz somewhere. Here- http://forums.hybridz.org/topic/88025-installing-tokico-280z-hp-springs-in-a-240z/

The Engine tuneup chapter, Checking and Adjusting timing, shows what you should be seeing as far as the adjustment lock-down screw. That's a screw head in a slot, between the arrows. And the Engine Mechanical chapter, page EM-25 (1976 FSM) shows what you should see down the hole with the distributor out, with a description of the side to which the tang should be offset ("the smaller bow-shape will be faced toward the front". It will make sense when you're looking at it. With no lock-down screw you can pull the distributor right out by hand.

Looks like your distributor is in backwards. The hole that would take the screw that went through the slot on the other side of the distributor base is covered. There are several ways that this could happen. I've heard that some people have been able to force the distributor in 180 degrees off, or your oil pump is installed incorrectly, or someone took the distributor apart and put it back together backward, etc. It does need to be locked down though. There are workarounds you could try or you can run through the oil pump and distributor installation procedures in the FSM to see what's off. Put the timing mark on zero and see where the distributor drive tang is oriented first (take the distributor out and look down the hole).

Strap your battery down before driving. You can make your own with parts from any auto parts store.

Pretty sure that only the Pope is allowed to do this.