Zed Head

Because when it's all over you know you've accomplished something and you feel a lot better. But you never want to do it again. Just spent a couple of hours replacing my EFI - Pump relay because it seemed to be sticking, Then found that it was probably just a corroded connection. But I re-remembered a bunch of stuff and diagrammed the EFI pins. And cleaned up the old one so it would look shiny on my desk.

Got a camera? Many people get their sensors mixed up and spend time working on the wrong stuff. All of the wires up there are white.

It was the late 90's. The microbrews were happening but I don't remember Conshohocken having a retail beer although I do seem to remember a place across the Schuylkill (yes folks, all of these names are real), that had a microbrewery inside. I think they were only house beers then, maybe. That was back when you could only buy beer from those big drive-through beer warehouses, a case at a time. Always felt like I was talking to mob people when I went there. The Philly area has many unique attributes. Like a "normal" pizza is just crust and cheese. What do you want all of that other stuff on there for?

Can't hurt to try Rockauto. Shouldn't cost much to ship just the module back if they'll take it. You have a pretty good case since the old one worked and the new one didn't. If the math works out, it works out. Those modules alone are spendy. Although, it's possible that the old one just works with a screwed up system, and the new one requires everything to be right. I think it has something to do with floating logic states due to no power to the terminals (SteveJ or Captain Obvious would know). The old one might be more robust to problems. Ignition modules are odd things. I had one, a GM HEI module, that showed spark with a plug out an on a wire but the spark wasn't hot enough to start the engine. I injured the module by leaving two plug wires off by accident and running the engine. That extra terminal does the same thing as the extra set of points or pickups on the earlier distributors. Just advances spark when the engine is cold. For emissions, I believe. You could delete that function and replace the module with a GM HEI module, if you want to save some money in the future.

The Fuel Injection Guidebook makes it easy to check much of the EFI system right from the ECU connector, where it matters. A meter, the guidebook, pen and paper, and you can confirm that most of the system is either right or wrong. Worth doing at least once just so you know. The 1975 book will have almost everything you need, but the 1980 book covers all years and will be exact. http://www.xenons130.com/reference.html Stuff like this. So comforting...

If you do do the swap, you'll need to be aware of the brake check warning lamp relay. It can wait though. Get rid of the Haynes manual and get the 1976 FSM. You can find it in the link in SteveJ's sig, or at the link below. Also download the Fuel Injection Guidebook. Pretty sure that the parts stores can check your VR also. It's under the relay shelf in front of the battery. Described in the Engine Electrical chapter of the FSM. You'll want to check that too. Many of those shoddy connections are stock from the factory. They're not as bad as they look, but they should be covered. http://www.nicoclub.com/FSM/280z/ (files open directly, no unzipping needed)

Just realized that old fuel filters have some pretty nice hose fittings of the proper size. Hard to find in the hardware stores.

The first thing sounds like the fairly typical lean spot in the AFM. A potentiometer in the coolant temperature circuit might help that. The second one could be sticky linkage, as noted, or stuck dashpot (the little thing with the "Sorry" game piece on top - not a vacuum fitting), or loose throttle return spring, or gummed up throttle blade/body. My 76 had all four of those problems. The third one sounds like either an ignition module gone bad, or an ECU, or ECU connection, going bad. If you have good spark it might be the second, if not, the first. Check for spark, and check the ECU connection. Could also be the coolant temperature sensor connection. It would run well cold, the flood when it got hot. Check plug quality, check for spark. If they're clean and you have it, try starting fluid. Watch the tach needle, if it jumps all over the place, that might be a module problem.

Back to square one, the disconnected tachometer that started it all - is it possible that something is screwed up in those connections? Have you measured voltage at the coil? While running?

That's a good example of the load problem. I was probably off on the bad battery as the cause since the current has to go somewhere. The fact that the battery showed as fully charged would mean that current output dropped (assuming that's what the tester measures). Could be that the bad regulator boiled the battery, leading to the test results. That happened to me with a 74 Dart Sport. The battery survived but the ignition module didn't. I don't really like the "one wire" setups. I assume that your ammeter doesn't work? Since it's unconnected. No indication of problems until it's too late.

Could have been a 73 build 74 260Z. 260Z was the introduction of the transistorized ignition in the states. As I understand things.

The 7 years and 5K miles put a new spin on things though. Same car? What changed from when it worked and now, when it doesn't? Love a good puzzle.

You bring up a good point, maybe unintentionally. No offense. He has one of these - http://www.datsunstore.com/high-output-alternator-p-1.html Which are wired as "one wire" alternators, apparently, by the description. Maybe he left something plugged in that shouldn't be and it's messing things up. "These are internally regulated units and bolt right onto your z or other Datsun just like a stock alternator. For the externally regulated vehicles, all you have to do is unplug your voltage regulator and tape off the connection. All stock Datsuns use an external regulator up through 1977. You don't have to use the T plug in that goes in the back of the stock alternator either, just tape it off and lay it over to the side." I wasn't saying the alternator is over-stressed, just that it was at maximum output, Which means maximum torque required on the belt. Which is why Oliver specified a special deep V (high contact) belt. Because the stock belts slip.

By the way, my numbers and theory may not be exact on my "dead cell" guess. I think it's more complicated than that But, still, I would not replace an alternator if the battery is no good. You just don't know what's what.

So if the battery is fully charged but reads as bad, that would probably be incorrect voltage. A dead cell maybe (6 x 21 V each). A dead cell would show 10.5 volts (5 x 2.1), but no current flow. And the machine might read the 10.5 volts as bad regulator. Might also be why the alternator is working so hard to charge, pumping out full current and making the belt slip. If you have a meter you can measure battery voltage yourself. While stopped and with the engine running. It will give you more details than the pass-fail of the parts store tester. Not disagreeing with Diseazd,we posted at the same time. But I would fix the battery first and then make sure the alternator is really bad.

Some of the people who run those machines don't really know what the test is telling them. They just hook it up and read the display. Did they test it on the car or each individually? If you have two components testing bad in the same system, you may be getting one affecting the other, giving erroneous results.

Points? You should be able to turn the engine or distributor to where the points are closed (said open before), then open and close them by hand to see if the coil discharges. You can also measure coil voltage and ground at the points. They have to open completely and close for the spark to be produced. Sorry, may not be the best system. I like to follow the paths and see what's not happening that's supposed to.

http://community.ratsun.net/topic/56630-e12-92-retard-or-no-retard/

Which module is on the distributor? E12-80 style with just one connection, or the E12-92/93, with two? Some people have reported problems with the modules that have the extra terminals.

I've spent some time in the south. Y'all is a useful term, and has no simple equivalent. Also spent some time in the Philly area. Around West Conshohocken, and King of Prussia. Drank more than a few Yuenglings in Manayunk.

Neither of those Dropbox videos will play on my system. Don't know if it needs a sign-in or what. He says that it runs now, but very poorly, so the tach and igntion system seem to be powered. Considering that the plugs were fouled when there was no spark, I would install new, clean plugs, set everything back to where it was, and try again.

I was kidding. Curious though if y'all are including the relief volume in your CR calculations. Difficult to measure but should be included.

Burn!

When it didn't start the first time, did you mess with anything before you reinstalled the tach? Plug wires, maybe? Kind of sounds like the firing order is reversed.

Forgot about that. You have an odd problem. Kind of hard to grasp without actually seeing it happen. Just one cylinder losing spark at mid-range RPM just doesn't make sense. If ir were my problem I would spend a lot of time confirming that that is really happening.