Zed Head

Bummer that you were short on time. Good though, that you got injector operation. Narrows things down a little more. I wish that you had run the other coil grounding test (three taps and a click). That would have shown if the ECU could work with the proper Pin 1 signal. Grounding the coil is like the best on-off ignition module signal the ECU will see. If you're going to have it towed if the 75 ECU doesn't work it doesn't really matter right now anyway. The 1975 and 1976 EFI diagrams are identical as are the the engine parts. Operation should be identical, it's probably just a different set of electrical components in the ECU box to do the same functions.

Rotsun appears at about minute 31...

I don't know whether to hope you need the ECU or not. If you do get clicks from directly grounding the connectors, then find on Monday that the 75 ECU gets the car home, there's somebody selling a 1978 ECU on Hybridz. Good luck.

I do know the shims make a difference. I thought the arrow pointed in the direction of rotation. Which appears to be up. Datsun 240Z/260Z/280Z Front Brake (Disc Brake)

That seems to be the case. I've recently read, on a thread on the forum somewhere, that some of contacts of the early ignition switches lose power for a moment when switching from Start to On. Something to be aware of.

Here's a little extra info, in addition to Carl Beck's. In case the unit doesn't come with its own or to plan ahead. http://prestoliteperformance.com/media/instructions/mallory/Mallory_Instructions_unilite_distributor_37_38_45_47.pdf

People often overlook the bumpstops. Strut mounts (insulators) are usually replaced when they fail from the weight of the suspension hanging from them when the car is jacked up. You might consider the basics (for that many miles), like the mustache bar bushings, the differential mount, and the inner transverse link (aka control arm) bushings. All easy to get to and easy to replace while the back end is up. Also consider the transmission mount (called rear engine mount by Nissan). All of those parts tend to get loose over time and miles.

You didn't mention the basic test for air in the system, pumping the pedal. If you can pump the pedal up, there's air, if pumping has no effect there's an adjustment problem.

"Seems sorta sluggish" is relative. Is your other car a Corvette? Exhaust leaks and vacuum leaks are not the same thing. I would do a full tune-up before going crazy on parts. One thing that often gets overlooked, for people coming from the hydraulic lifter Chevy, or US domestic, world is valve lash. It's critical to good performance. Index of /FSM/280z

They are different, sometimes, in ways that I'm not clear on. But the injector grounding circuit is the same. It might give you enough to get the engine started and get the car home. I had a 76 and 78 280Z with exactly the same ECU's, but the number on that 1975 ECU is different. I only suggest it because it's cheap, $25, and might tell you something, if you get to the point where the ECU is the only possible source. The weird thing about your situation is that the engine ran when you drove it over there and then it just sat. The ECU is in a fairly dry spot and I think that they probably go bad from usage not sittage. Odds are something strange happened like your gas tank filled of water. It happened to EuroDat and he was using his car. If your guy decides to really go for it with some time, he might run a hose from a gas can to the inlet of the fuel pump with fresh gas. Especially if the injectors click.

A 1/2" spacer to make the body fit the tube is not much. And the fact the the spring is loose at full extension just means the Staggs have more travel than the originals, or the shaft is longer. Which could mean that you're bottomed out sooner. What you really want to know is the length of the shock, from bottom of the body to mounting point of the shaft, at full extension and full compression. Dimensions are hard to find, for any shock, and not many people consider the extremes, full extension and full compression, and what it means during usage. We're all accustomed to replacing stock parts so don't do all of the math that we should. If you can see the shaft you might be able to estimate or measure travel to bottom and get an idea of what's happening. If there's a boot/bellows on it will be difficult. Search 73598 (Monroe front) and 361002 (KYB front) on Rockauto and you'll see how things can vary (although that 14" stroke is suspect). Or just go to Suspension for a 78 280Z. You can be in the travel zone at rest but closer to top or bottom depending on which brand you're using. I've not seen the Stagg numbers although they might be out there somewhere.

I notice that you haven't mentioned your fuel map at all. Makes me think that you may not understand exactly how Megasquirt works. It doesn't adjust itself, you have to give it the right starting point, then tune it from there. It takes quite a bit of work to get it tuned right. Have you been on the DIY site? Spend some time here - https://www.diyautotune.com/faq/faq.htm

Here's a cheap ECU that might be worth a shot, for testing. Should work even if the numbers aren't a perfect match. The differences are minor among the variations. 280z parts/ FREE L24 / Price drop - Parts for Sale - HybridZ And superlen has been known to loan an ECU I believe. He has collected a bunch for his project. http://www.classiczcars.com/forums/fuel-injection-s30/51601-hellfire-status-release-date-annouced-2.html#post463189

This discussion comes up often, but there are many things that affect ride, like tires (profile), bushings (urethane or rubber), shocks, springs. After a while, you'll get used to it and your BMW will feel like it's disconnected from the ground. You'll miss the road feel of the Z.

The common problem appears to be where the wires to the connector bend and poke in to their holes. They flex and fatigue over time. I think that you'll need a magnifying glass to see any cracks. FastWoman reflowed hers, she might have some tips.

I used a black Sharpie (magic marker) on mine. Don't even have to to remove them.

If the diff is available you might consider getting it also. The 79 ZX had a variety of diffs but at least it will match the transmission. Euro, I thought the same on the transmission but the FSM says that 72 still had the 3.592 first gear, not the later 3.321. It also says that it has a 3.9 diff ratio though, which would give a very low 14:1 overall first. I'm not sure the FSM numbers are right though, the 240Z guys would know for sure. Anyway, it's definitely doable. Good luck.

What car? 240 or 280? The ride was stiff compared to before or just in general? How much slack? Are the springs red (Tokico's are red and don't require a compressor)? Interesting that the Staggs have more travel. It's a new product so information is scarce. Nobody has reported anything more than minor oddities though, which is good.

You kind of went backward but still got to where you need to be. Most of the threads I've seen on bad ECU's start with people tapping them to fix them, not make them go bad. But that is the sign. Reflowing the solder joints on the connector pins in the ECU itself has fixed it for some people.

You got a lot done in a short time. Impressive. I like the bailing wire puller trick, I did similar with an adjustable pipe clamp on a two jaw puller, to break a bearing loose and pull it. I think I took a picture for the record just because it looked so bad. Found it...

In principle, theory, on paper, in your mind, it's a pretty easy bolt-in swap. You might just need to retune the SU's for the bigger engine (I don't know SU's). The dimensions of the parts are the same. In reality, you'll break a bunch of bolts and studs when removing various parts, like manifolds or exhaust pipes. So you just need to be prepared to fix some broken stuff. If you really want to be prepared you'll have some taps and tap drills waiting and just decide to replace parts that might or might not need it, like manifold bolts or studs. I'm not sure, but I think that the 240Z exhaust manifold and exhaust system might be a little restrictive for a bigger motor. I think that they're restrictive for the stock L24 even before you start. The pipes look small compared to 280Z pipes (you'll see if you compare). The 5 speed transmission will bolt right in. The shifter or shifter opening might need some work, or not, 1972 might be big enough. Early cars couldn't handle the throw of the 5th gear position. Overall, it's easy. But the broken bolts will be aggravating. And, of course, there's the "what should I do while I have it out" project bloat. Clutch, flywheel resurface, rear main seal, transmission front seal...etc.

Listen for the clicks first. With no sounds but the tap of that jumper wire, either grounding the injectors directly, or grounding the coil you'll hear if the injectors are even opening. I would do both tests, first ground the pins at the ECU as FW originally suggested to verify that the injectors have power and will work, then ground the coil - to see if the ECU can do the same job. A jumper wire, the key, a charged battery (don't forget that), and you'll know much more.

That's a good point on the vacuum leak. An old-timey mechanic might have the oil filler cap off to listen for noise or something, not realizing that that would be a massive vacuum leak. Everything needs to be buttoned up tight. Too bad the garage owner's not on the forum.

Sorry FW I thought that you had mentioned the "grounding the negative post" test but I couldn't find it when I looked back. It doesn't seem very sophisticated, creating sparks and ozone, but it does test a big chunk of the system, in series and connected. Seems like it should be an FSM test.

I threw the gas idea out there on the assumption that the ECU and injectors are actually working correctly. A big problem here is that nobody really knows if the garage owner knows how to test that the injectors are getting grounded or not. Since it runs on starting fluid, seems like there are two feasible possibilities - the injectors aren't opening or they are opening but they're squirting bad gas. Hard to say which is more likely. But the fact that it does run with starting fluid is significant, since it means that the plugs aren't fouled. Overall, it's still looking like the ECU is not properly grounding the injectors. There is a test that you can do that will tell pretty surely if the circuit to the ECU is correct and if the injectors are opening. Connect a jumper wire to the negative post of the coil, leaving one end free. Turn the key On. Tap the free end of the jumper to ground quickly. Every three taps the injectors should click, all six of them. With no engine cranking and no extra noise, it will be easy to hear the injectors. If you get a spark at the wire on every tap, which you should, but no noise from the injectors, then something is wrong. At least you'll be back to a focus on the ECU and the Pin 1 circuit.