Zed Head

Took a look through the FSM's and see that the "atmospheric pressure signal" didn't show up until 1977. California models only. Page EF-7 in the 76-78 FSM's (not shown in 76, shown in 77). Pins 12 and 9 on EF-25 in the 77 book (now called an altitude switch, shown right next to the ECU). EF-23 confirms it's just a switch. Weird stuff. What's really interesting is that to "go lean" the ECU looks like it changes the resistance on the pin 9 circuit. Might give a clue on another way to tweak the mixture. Maybe the thing shown in the AFM is the reference resistance for the circuit and decreasing its resistance leans the mixture. I'm guessing that Pin 12 is another resistance, added in parallel to pin 9. Someone else with more electrical would know better.

The two white wires have been discussed before. They're "Control Unit Checking Terminals". Can't remember where the altitude wires come out of the harness. You could probably use them to do the same as lowering fuel pressure though. Quick fix. I think that they just need to be shorted, the altitude "sensor" is really just a normally open switch if I recall right. Edit - Actually, superlen and I had an exchange about the wires in a past thread. Apparently there are extra black wires and extra white wires depending on the harness. Probably best to trace the wires to the pins to know exactly what's what. The FSM describes the altitude switch and probably has the diagram back to the pins. You could probably wire in your own switch if you wanted to try it or jump it with some test leads to check it out.

With the switch to encapsulated shock mechanisms it makes you wonder if you shouldn't drill a small hole in the strut tube to let moisture out. Condensation happens everywhere, along with leakage from the gland nut area and it will sink to the bottom of the oil pool at the bottom of the tube. If I was doing my mine again I'd probably drill a hole (undecided as to where) then grease up the shock body with heavy grease before installation. Leave the strut tube dry and the heat from the hub will probably keep it dry. Just thinking. With KYB's or Tokico's the system is not the same as designed.

I've found that the combination of parts can affect the way the engine runs. By parts, I mean the ECU, AFM, injectors, coolant temperature sensor, grounds, etc. I've had a lean-running engine and a rich-running engine with the same AFM, but various other changes. I'm not positive what exactly made the same AFM give a different air-fuel ratio, since I've improved grounds, changed my power supply set-up, swapped injectors, and ECU's, in between. I put an AFM that used to run rich back on my engine because I had since installed an adjustable fuel pressure regulator (thought I could now go low on fuel pressure and use the better AFM) and found that it was now lean at the same pressure as before (I used a potentiometer to tweak it richer and it works great now). So if I was starting with an unknown system the one modification I would make, to start, would be a good adjustable FPR. Then you can go lean or rich. On a stock engine the curve is probably right, it just needs to be moved up or down, as a whole. An adjustable FPR might be that final fine tune to get you away from rich. Drop the fuel pressure 1-5 psi, it won't have a huge affect on spray pattern since Nissan went with the narrow stream on their injectors.

To be clear, you can go to your local Nissan dealer and ask for the nuts and washers for your engine and they will probably have them or be able to get them in a few days. They're about the same cost as the MSA kit. I went through the whole "what should I use" issue and found that my local dealer could get them. Why not go stock? And, expanding on Post #2, I think that Nissan doesn't even use washers, of any kind, on the "yokes" (the thick shaped "washers"). It's just a nut, the yoke and the manifold (study the diagram in Post #2). Lock washers are over-rated and give a false sense of security. I've disassembled a few L6 engines and many don't have washers. If the nuts seem loose after running it's probably the manifold gasket shrinking from the heat and pressure and things moving around after some heat cycles. It's not the nuts loosening. I haven't done a manifold recently but the next time I do I will be polishing up the surface of the yokes so that the nuts can seat correctly (sitting top of rust is bad) and the yokes can self-adjust, and use the stock Nissan nuts. I might even go for a factory gasket, depending on timing and funds.

That's some great internet detective work. I wanted to see more pictures though, so I went to my favorite economy site, Rockauto.com, and the pictures didn't look like your EMPI part. So I plugged your EMPI numbers in to the Google and found an EBay link that suggests the car would be a 92-99 Nissan Sentra. Just helping get the most out of your work. Makes me want to go rebuild my rack now. I know I'll be checking the boots/bellows for damage next time I get a chance. Empi 48204 53Y25 Power Steering Rack Boot Kit Fits Nissan | eBay (check the interchange number in "item specifics") Edit - Maybe I'm just muddying up the thread but it looks like that 88-1509 bellows fits several cars. Found another EMPI catalog. Looks like 88-1527 does fit the Miatas. Probably best to just get the EMPI brand 88-1509 part rather than a boot that fits the car. Anyway, thanks for sharing! http://www.empius.com/bcatalog/PDFs/2013_B_Catalog.pdf

You could go to the hardware store and get self-locking nuts (steel out-of-round, not nylon). The part number for the original Nissan nuts is in the link in Post #2, but I don't know for sure that they're self-locking (I've never seen new ones). I used the MSA gear on my first gasket change and I had little room for the nuts and hardware also. I used the MSA gasket, which is thick. The studs are only supposed to be finger tight when installing, if you double-nutted them and drove them in to the head you lost room to work. Apparently, if you get the right group of parts, you can mount the exhaust manifold using the three inner bolts, start the nuts and washers on all of the studs, and slip the intake manifold between the washers and the head. I've never had enough room to do that myself, but it's been described.

You do know what you're looking for, right? The wire or component that has zero or very low resistance. Just leave your meter connected to the green and black wires and connect and disconnect things until you find the thing that causes very low resistance. That low resistance is what allows the current to flow that overheats and blows the fuse.

I saw that video. Note that it's really a comparison of distributors AND their ignition systems. Maybe old worn distributors using the Pertronix and points systems too (as noted in the comments). If they had installed the Pertronix and points in place of the 123 ignition system, in the 123 distributor, that would be meaningful, comparing ignition systems. It doesn't tell how a new distributor with points or Pertronix would perform. Again, not trying to be a downer, but sales is sales.

What kind of wear? Even across the tread, one side only, cupped pattern on the edge, etc. A picture would be good.

The ignition system might be worth getting. Your 260Z already has electronic ignition though, but the 83 Maxima might be a little more developed (higher energy). It won't have the E12-80 module though, so you'd have swap one in or figure out how to make the other module work (it will have more pins). The brakes are disc, so nothing there. The diff maybe, I think it's an R180, you might have an R200 though, so little benefit. The Maxima uses a different suspension system, trailing link in the back, not sure on the front. Not much to get really, the 5 speeds swap over but you're looking at an auto. You could swap the complete L24E engine and EFI system in (assuming it's not a diesel). It would fit. The exhaust system might need work though.

The switchable curves were discussed somewhat in the Hybridz thread - 123ignition - Nissan L6 Forum - HybridZ They're not typical L6 engine curves. Many peak at very high RPM, compared to where the typical L6 Nissan curves peak. Open this link (the manual for the switchable dist.) and go to the bottom and you'll see the options. They appear to be shown in crankshaft RPM (unless they're set up for 9,000 RPM engines). http://www.123ignitionusa.com/123gb6rv.pdf Looks like they're shown for 10 degrees starting point (idle advance).

You could also use a battery and alligator clips with a light at the power wires in the connector. I do it with gauges on the bench. I don't think it will hurt your meter to turn the dial to other resistance ranges while it's connected. Most meters are able to give an actual number, even no resistance has some resistance. On the meter usage - a typical meter test is to touch the two probes together to check the battery and probe connections to the meter. If everything is right you should the very, very low reading or zero, for no resistance. Then you'll know for sure what no to low resistance looks like on the meter.

What brand of meter are you using? 001 might just mean "out of range". You might consider a test light in place of the fuse. Disconnect everything, insert a light in place of the fuse, either built yourself with alligator clips and wire, or one from the parts store, apply power to the system, then reconnect each item. The shorted component or wire will cause the test light to glow the brightest, but the light bulb will protect the circuit from too much current. I didn't follow out the wiring diagrams but it could be something as simple as a shorted gauge bulb, or bulb socket. The little BA9 bulbs have their electrodes in close proximity.

Those bushings shows as a replaceable item but don't appear to be available (on courtesyparts.com anyway). That grease looks pretty solid, do you think it was doing any lubricating? Datsun 240Z/260Z/280Z Steering Gear (Rack & Pinion Type)

You're missing the point TH. It's a new distributor with tunable advance curves, bolt-in. Anyone who's tried to fine-tune the advance curves on their mechanical distributor for better performance, both driveability and power, would know how difficult that is. It's not about fancy. You can't tune an L28E's ignition curve either.

Many people don't like this guy, with his personality problems, but credit must be given. "123 Ignition" Distributor Replacement for Nissan L4/L6 - Nissan L6 Forum - HybridZ The activity on the thread drove the US distributor (of these distributors) to source a manufacturer for the adapters. Credit also to 280zex in that thread since he's the guy that really wanted one for his blow-through turbo engine. He apologized for his early misunderstanding and might be the first Z guy to buy one. The thread really made the US rep realize what he needed to do to get them to the market. They've been around since at least 2004, I've seen Alfa Romeo threads out there, but the emphasis has been on the Euro cars. It's weird that they've been invisible to the Datsun world for so long. It's a great idea and adds easy timing tuning for the carb guys. Edit - I'm not trying to downplay the significance of trying something totally new. Just thought people would be interested in how things developed. The US rep didn't even plan to produce an adapter for the L engine. Parallel paths, weird coincidence, the other guy has his engine running too - http://forums.hybridz.org/topic/116989-123ignition-system/#entry1096684

Page 9 of this document says it's a Mitsuba. http://www.xenons30.com/files/1973%20240z%201974%20260z%20fuel%20system%20modifications.pdf Brand, I assume. If you search Mitsuba fuel pump on the internet you'll find many links to read. Maybe a filter from another model will fit. The big manufacturers tend to use common parts for many models.

Looks interesting, that's a lot of pieces in a small unit for ~$2.50 each. Do you know if the LEDs are in series or parallel? Probably series so that they can use one resistor, maybe? I hope the longevity is good. I was describing my LED bulb fabrication to my dentist and he said that he had bought some LED lights for his shop with a twenty year guarantee but they didn't last near twenty. Three, I think he said. Not to be a downer but new technology always has its issues. Those look like they'd work great for the Z's though, with the potentiometer control.

I don't know how much effect the cushioning plate would have. You're right about the pressure plate. The disc and pressure plate are most likely designed as a set. I knew there was another name for the plate and found it, it's "marcel spring". Found another picture also. The picture is from this thread (Southbend...), which has a lot of griping and misinformed comments in it but also has some insight on the function of the marcel spring. Might be getting off-topic but you don't get many opportunities to talk about the odd little pieces. Post #21 might be the most informative but he doesn't give a reference. The Google could probably find it. (Found it - http://www.btc-bci.com/~billben/clutch.htm). Also found the original source of the picture - http://www.mooregoodink.com/news/rams-powergrip-clutch-greater-clamping-pressures-without-sacrificing-drivability/

Quoting myself. I dug around and found a good image of the center of the disc. Exedy calls it a "cushioning plate". Halfway down the page here - EXEDY - Clutch Info

After you check the things above, if you don't find anything wrong, open up the 1980 Engine Fuel chapter here - Index of /FSM/280z And use the 1980 280Z/280ZX Electronic Fuel Injection Guide (aka Bible) here - XenonS130 - S130 Reference The cylinder head temperature sensor (CHTS), or coolant temperature sensor, is one important circuit to check for rich running. The Guide has good diagrams of the pins to check at the ECU connector. The two books together are great for really understanding the system. You'll need an ohm-meter.

1985, that's about 29 years. Check the engine parts well before trying to turn it over and you might save some damage. Pull the valve cover and lube the cam and valve train, pull the plugs and squirt a few cc's of oil in, let it sit for a while to get the oil distributed, etc. stuff like that... Purge the fuel system, check the cooling system for rust (I've seen some water pumps with a water mark and rust on half the impeller). Get new tires, old ones can look fine but fail catastrophically. Check the air ducts for mice nests.

atlanticz has a few odd wiring diagrams. Something might show itself. Z Tech Tips Electrical (AtlanticZ.ca)

The 60 to 65 mph news is a good fact. Everything from wheels to driveshaft increase RPM proportionally to road speed. The "horrenodus" part of your earlier description also sounds like a high inertia object, wither heavy or large range of motion. The driveshaft or a wheel both fit. jmortensen's price on that driveshaft is a good one, and they're hard to find. Plus he used to be a part of a company that did driveline work, M2 Differentials, so the work on the driveshaft is probably right. You might pick that up and try it. $50 for a spare part and a cheap diagnostic tool. You might also swap your spare tire for each of the four to see if one of them has an effect. Did you remove the rear wheels when you replaced the diff? Maybe one of the wheels is bent and ended up in a new spot.