Captain Obvious

Shouldn't be... The non-quartz control board is shunt zener regulated. Unless you're trying to run it off a pair of D cells, it should be just fine. Even a 9V battery should power it just fine for quite a long time. Of course the quartz movement could (should?) be more accurate, but not because of the input voltage variation.

Would be interesting to use the timing light while the problem is occurring, but since it only occurs under load, that's a little tricky. Would add value to see if the timing light was skipping beats at 2K when under load, but might not be feasible. If the wires are long enough, maybe run the timing light wires out of the engine compartment and into the pass side window and take it for a drive while a passenger mans the gun? :laugh: You wouldn't be as concerned with the absolute value, just that it was consistent, steady and not skipping beats.

There's some 78 fuel pump info in this thread: http://www.classiczcars.com/forums/fuel-injection-s30/50487-runs-nice-few-min-then-rough-then-kills.html Starts about halfway down or so?

Very broad brush, but often... Low RPM miss is ignition. High RPM miss is fuel. Your experience with the choke lever and nozzle level seems to support that broad brush. I'd be looking for something electrical.

I'm not from that part of the world so it's speculative, but I've been told you never slow down, you never grow old.

I saw that first sign on Craigslist in one of my occasional trolls. It's close to me so if you want it, I can be local eyes to check it out for ya. [ATTACH=CONFIG]67565[/ATTACH] And there's no price In the ad... If someone contacts this guy and gets a price, let us know, OK?

Duh. Pennsylvania of course. The rest of you guys have recto-cranial inversion. :laugh:

Well if you ever decide that you would like something a little more vintage, I've got a 77 that I'd probably be willing to trade. Just let me know... I'll be holding my breath.

That's awesome! I've got three times that mileage on my Z and I consider it "low" compared to it's siblings. You wouldn't happen to be original owner, would you?

Awesome! The knowledge in this place is amazing!!

I heard that the design was done for North America and the RHD stuff was an afterthought. :laugh:

Here's some of my lock experience. Some of the pics might help? http://www.classiczcars.com/forums/misc-s30/44869-lock-rebuilding-internal-parts-ignition-doors-hatch.html

30K or 130K?

Sitting on a leather something... Briefcase? Chair? Wallet?

Great pics. One thing that was amazing was the amount of mirror image they did for the RHD cars. Two completely different cars from the dash forward. One thing that caught my eye, however, was that they did NOT redesign the center console. They used the same center console and ebrake assy on both RHD and LHD versions.

Another tip. Make sure you take the gas cap off and release any pressure in the fuel tank before you go opening the system. If you don't you might run into a situation where fuel seemingly defies the laws of physics runs uphill for no explainable reason. Well there is a reason... The fuel vapor pressure in the tank is pushing fuel up that hill. Not that this took me two hours to figure out or anything... :stupid:

Gotcha. On the good side, the fact that the problem persists makes it easier to find. So with what you have described, it could be a huge scope of things. Could be fuel or spark. Anything from an intermittent electrical connection inside the ignition module to crud in the fuel tank blocking the pickup screen. Next time it happens, check for spark. That could narrow the scope significantly. Like zKars described it's a hunt, but the hope is to narrow the hunt as quickly as possible.

My first blush advice would be to start simple. Attempt to determine if the problem is spark or fuel. When the problem is occurring, pull the coil wire and see if you have spark. I couldn't tell from your description... When the engine dies, does it restart or does it just crank and crank and not start?

Probably not directly applicable, but here's some info on how the temperature switch works and it's affect on timing, etc. Might be some stuff in here that helps. http://www.classiczcars.com/forums/electrical-s30/46647-water-temp-switch-what-does.html

Sounds like you've got a lot of air going through that valve cover vent hose and into the throttle body nipple without going through the AFM first. That will cause a lean condition. So, where is that air coming from? Some things to look at: Make sure that the PCV valve and it's hose are in good shape and properly connected. (The PCV and hose are located on the underside of the intake manifold right behind the throttle body.) Make sure you've got the oil cap installed and snug. Make sure you've got the dipstick installed and pushed all the way home.

I'm no expert on the topic of idle air valves, but I believe it goes like this: If the valve has two wires, it's a PWM control with one field coil fighting against a spring. Simplest, but not the fastest response time. If the valve has three wires, it's a PWM balancing between two field coils. More complicated, but faster response. If the valve has four wires, there's a stepper motor inside. More complicated, but stays positively where you left it with no input signals. Example is GM. I thought about the concept of just having two idle speeds "cold" and "normal" and just using a small simple solenoid valve to open up a bypass around the throttle plate. I've seen some really nice small solenoid valves used for EVAP can purge functions on cars. Maybe I'll grab one of those and mess around.

I think a trip to the junkyard is in order. I'll have to make sure I take a ruler along...

I'm not sure I know what you mean when you say that you can't get the idle "back to where it should be". Are you talking quality or quantity? By that, I mean... Are you saying that the idle quality is poor (stumbles, runs rough, etc) or are you saying that the idle quality is OK, but it simply idles at too high of an RPM?

Well I surely wouldn't claim to be either a Z or an EFI expert, but I'd be happy to lend a hand if I weren't on the other coast. Good luck on the endeavor and if there's anything that can be done remotely, make sure the forum is on call at the time?

Hmmm... I've got my AAR adjusted such that I don't get much of an idle boost when first started, but I don't think my engine would idle stone cold without it. My idle settles out to 700-800 once warmed up, but I think if I cut it out completely, I'd have to sit there with my foot on the pedal for the first minute to keep it from stalling. Maybe I'll try that and see what happens.