Zed Head

You can also take a piece of wire and connect it to the solenoid small terminal then touch the other end to the battery positive post. A poor man's remote starter switch. Cliff/site's suggestion is the quick and easy way, but using a piece of wire adds some convenience. Supplying battery power to the small solenoid terminal is exactly what the ignition wire does. It will actuate the solenoid which will move the plunger and cause the starter to turn and the gear to engage the flywheel or flex plate.

No point in working on the starter if it's not getting power from the wire.

This might be one of them.

The "condenser on the negative post" might have come from a solution I developed in the past for a tachometer problem, and have recommended for the occasional odd tach problem, as a last resort. In my case, the needle would just sit and quiver until the condenser/capacitor was attached. My general theory was that it absorbed voltage spikes/noise that were causing the tachometer problems. Basically it cleaned up the voltage signal. Whatever the reason, it worked. I even confirmed it later when the wire broke off of the condenser and the tach quit working. That was with a GM HEI module though.

It did work when the engine was cranking, but stopped when the engine started. Might be a clue for the guys that know electronics. While cranking the overall system voltage will be lower. As soon as it starts you get alternator voltage. Do you have any spare E12-80 modules? Maybe the problem is there. Might be worth a swap, just to confirm. At low RPM the module will be "working harder" to limit current for "dwell control". I don't really understand the details of current-limiting but that's how the ZX and GM HEI modules work to get maximum coil charge without overheating the circuitry. And, of course, don't overlook the grounds. The module grounds through the distributor body and the distributor body grounds through a separate wire or the mounting pedestal.

The conversion parts and engine might make it worth the money. Even a Chevy manual transmission adds value. Who knows what diff the guy used. Too bad there's not more detail. https://jagsthatrun.com/collections/datsun-zx

You should check for power at the switch first. The odds of a new switch failing are slim.

Did you mean switch, not module? Can't remember the details of the first problem that caused you to replace the part, whatever it is. Maybe write a short history of problems up to now. There's not much to the system that sends power to the starter solenoid.

SU's use a piston to control air flow. Might be that your pistons are stuck, among other possibilities. Not sure how to fix that.

Is there a typo? Why would a shorted O2 sensor affect a cam sensor? And why would anything "burn up"? No fuses? Just wondering.

Might be the ignition switch. Fairly common for the pins in the switch to get loose and lose connection. Or for the mechanicals to wear and the key does not turn the electrical portion of the switch far enough. If you can get to the switch and take it apart you can get the definitive answer. Turn the electrical portion with a screwdriver and see if you get power then.

The Z switch is just a two wire switch. Power on one side and ground on the other. I converted mine in to a "headlights still on" warning buzzer.

Your battery is probably low on charge.

The switch above the brake pedal is known to break. Two wires and a spring loaded button. https://zcardepot.com/products/brake-light-switch?_pos=1&_sid=e77632f40&_ss=r

Hmmm.... https://www.classiczcars.com/forums/topic/63698-covid-19/?page=70#comment-623001

Oil is fascinating stuff. It's taken millions of years to be created but we're using it on the decades scale. You can find a ton of articles out there trying to explain the use of ethanol. But oil is just too easy. https://www.ag.ndsu.edu/energy/biofuels/energy-briefs/history-of-ethanol-production-and-policy

Ethanol's original reason for being used in automobiles was to reduce dependence on petrochemicals. In part to avoid the situation that exists with Russia and Saudi Arabia. Once the industry is created it tends to become self-sustaining.

Thanks for the response. But, Bad Dog is really just like us. I don't think that he has inside knowledge. Many people look at things like that and decide "what else could it be?" and let their imaginations create something. ennisdavis actually had a good point about the robustness of the piece. Plus the piece is not designed properly for a downward load. It would probably bend more easily than the tiedown loops on the front and back. I look at it and think that it might be for fixturing during manufacturing. But I don't know, it's just seems like a reasonable guess. Anyway, if somebody has another source that would be cool. Maybe Honsowetz or Monroe or Humble mention it one of their books. Maybe @katsknows, although it looks like they only showed up on 280Z's. Here's the part being discussed. And on a more whole car.

That is interesting. I've not heard that myself. Can you describe the source? No offense, but without it, it's just two opinions. We're all just people with Z's on the internet. p.s. I've read that the loops on the front and back are for tiedowns. But I haven't read that about those metal pieces on the body stiffeners.

I browsed through a bunch of carpartsmanual pages and only found one drawing of the thermostat housing, in EFI Control. It does show a side port but I can't find a switch defined for the hole anywhere on the other pages. The carparts site is setup in a way that you have to know something's purpose before you know where to find it on the site. http://www.carpartsmanual.com/datsun/Z-1969-1978/engine-280z/e-f-i/control

Most likely explanation might be that it has been in an accident in the past. Maybe hit a log while it was on the beach collecting salt.

They can last a long time before they are unusable. There are threads on the forum from people who took theirs apart and found signs of destruction even though the transmission still worked properly. Strips of bearing cage/retainer, loose ball bearings in the bottom of the transmission. Still worked.

I think that most of today's manual transmission cars use the clutch safety switch, not a neutral switch. So your first idea would match what a modern car uses. I have a 2003 vehicle and it has a clutch switch. If I start it thinking I'm in neutral but I'm not and let the clutch pedal up it will still jump forward (of course), just like a car without a switch. Does the second set of points really use the kickdown switch to change which set of points is used? I thought it was a temperature switch. Either way, all that matters is to be sure that the points have power under all driving conditions. Connecting the wires together should work, but there are probably other ways, like just bypassing the switch itself, or shorting it internally.