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I’m happy to report that after an afternoon and a half, my carbs are tuned! Thanks to everyone for the help! I had a blast figuring it out; definitely a lot easier than expected.

There are no switches (electro-mechanical devices) inside the ECU. There are lots of transistors (which can be used to "switch" current paths, but there is nothing elecrro-mechanical. Nothing moves inside the box except electrons. And as for it being a "computer" or not... I would say "not". To me, a "computer" would be a programmed device running a sequence of decision making steps, and the old analog ECU's do none of that. There are no "steps", and there are no decisions. I have not, however, looked up or researched in any way what a "computer" is by definition. But I can tell you there is nothing programmable inside the ECU's, at least through the end of the first gen Z run. Some of the later ZX's have embedded computers inside, but nothing before the ZX.

1 - is your voltage regulator. 2 - is (what's left of) a condenser that is supposed to tie into a blue wire that goes to the voltage regulator (among other things). It's purpose is to filter out electrical noise. 3- is your air conditioner compressor relay. Closes when the system is calling for cool.

Let me be the first to be controversial and I know this isn’t the question you asked: I fundamentally disagree with doing them hot! Reason? Can you keep the engine temp constant at “hot” over the 30-60 mins it takes to do the job? But cold is not going to fluctuate. My personal experience has been that by the time I finish and go back to cyl 1 to double check, the clearances have changed! ;) So for a rookie like me, I like doing them cold. Secondly, this web page I LOVE: https://www.engine-specs.net/nissan/l28.html I do mine a fraction tighter than spec but let me not elaborate with an essay as to why.

Set them cold and check them hot to verify. If anything is a tad off, I can adjust one or two while it's still hot.

There is no Z35. The chassis designation is still Z34. The Nissan Z is slated to be a 2023 model, not 2022. The rules in the US allow Nissan to call it a 2023 model year car. As an example, I purchased a 2012 Ford Mustang in June 2011. I don't think there is any grist to mill here. Nissan has already announced that the base model will be the Sport, and the higher level trim is the Performance. And there will be 240 of the Proto Spec in yellow. If you want something to speculate about, I think we won't see much on any road tests of the new Z until it's close to the launch date, especially if they are making any late tweaks to compete with the Supra.

https://www.forbes.com/wheels/news/nissan-z-2023/ Keith

I've set them cold and hot. Both methods worked for me.

I always set my clearances cold when I'm going to run the engine cold.

I really might go that direction. It would be hard to abandon my vision for the car. Maybe ill just come back to it in the future That is one of the greatest things about these S30s. You can continue to work on them and change them

Yeah really! Way to let us all hanging here!!

They were talking about the "Proto Spec" edition of only 240 cars. Likely only available only in the lkuzachi yellow of the prototype and with features and interior treatment not available in the sport & performance trims.

If that is the question... There is a metal stack, welded to cowl substructure that keeps water from flowing into the fresh air intake. There is a flat piece of metal welded above it to prevent water from dropping into the stack

I've said it before, I can get the valves checked and adjusted in 15 to 20 minutes. So I always do them hot. Sure, when putting a fresh engine together, they need to be set cold, and the clearances need to be set accordingly. I also set them a bit tighter than the manual calls for. For racing it is a way to "cheat" a bit more lift and duration out of the cam profile.

This was actually yesterday, but [mention=17919]randalla[/mention] and I went to a local Cars and Coffee in Scottsdale. We're definitely at the low end of the cars that show up, but get more than our share of attention. The Delorean next to me looked brand new, the Jensen Healey next to Randy was sweet as well. Sent from my KB2005 using Tapatalk

I'm not sure what you mean by "vacuum". All carbs need vacuum. It's what makes them work. About the coolant... You can make the system work without coolant running through the carbs. About the temp control and anti-backfire stuff... You can make the system work without those. And about the documentation... Search around for the "Fuel System Modification" document for 73 and 74. Has lots of good pics and other carb goodies.

Oh yeah, and yes... A sticking AFM is an interesting idea. If it's sticky and not opening as far as it should be, you'll run lean. Just seems kinda hard to believe it would be intermittent like that. But whatever... It's better than anything I've got at this point which is absolutely nothing!

It really is a shame O2 sensors dont work since all modern cars use them to adjust the fuel mixture (sarc) 😣

Couldn’t agree more! My spare Beru cap I bought with the 123 purchase arrived with the centre electrode broken off!!! 123 charged me £45 for the worthless spare cap!! The one that it came fitted with, fell off while driving and very nearly stranded me in a dark fast road without a safe place to pull over :o . I eventually got it started on the battery’s last Joul and limped home to find the electrode sitting next to the aluminium ring inside the dizzy! I was very lucky it didn’t kill the mechanism inside!

Are those calipers for solid rotors, or vented rotors? I think there are two versions, aren’t there? It doesn’t look like you have the brake pads in there.

You might check your engine mounts. Maybe the engine is low and/or shifted.

After about a year of driving the 280zx i decided to do the engineroom and also refresh the seals of the L28. At first i thought that i would do this in a few years but as i discovered that the engine after 42 years (!) has a small water leak into one of the cylinders i thought i better do this now. The engine runs as new but it uses a little bit of coolingwater so i took it apart and as i expected it has a small leak near a cylinder.. it was the rear (6) cylinder! The seal was damaged there it had a kink in it.. wonder if that was since it came out of the factory because there are no clues that it was ever apart.. (still the very special orig. nuts on the exhaust flange.. and all the bolts and bits are originals.) Exhaustflange nuts (these where luckily the only ones that broke off besides one on the engine that i have already repaired..) So i need to do these 3 bolts in the exh.manifold... (I have sended these nuts with 35-40 kg of old parts to the company that passifies these parts so they come back as a very clean part.. drill them out, tap them and will try to reuse them!) Cylinders looked very good you can see the honing marks very good so no need to take the pistons out! Here i found the small leak into cylinder 6! If you look good at 3-4 o'clock on the seal around this cyl. then you can see that the seal was not very well installed on this head! it has a twist in the seal. next pic at 2-3 o'clock it is very clear to see that the seal was not installed very well! Very happy that it's just the seal that was faulty! Here a cleaned up version of the head .. it's a N42 head by the way. I took the head to a firm that revise engines and they cleaned it for me.. as the head is as straight as an arrow it does not need any work. I already cleaned the valves and renewed the stem-seals of them.. Also did a valve fitment check and ground the valves (for as far as necessary) with the special abrasives.. Taking the engine out pic.. Here a top-tip for when you restore springs.. The spring is on a little peace of sheetmetal so the cleaning can be done between the "rings" It comes back as a new one! I need to take these bolt-ends out.. if you have a tip other then drill them out i like to hear from you! (I try to get them out with some oil and if not then i cut them flat of and drill them out and tap new thread in it..) AH.. i will try to do it with heat.. but tell me, what do you do.. wait till its colder again or try to turn them when still reasonable hot? Has somebody used coldspray? i try that also on the bolt (not the manifold) .. (Just bought some penatraiting oil that also cools it.. the bolt will freeze!) Next job is cleaning up the rest/ and painting of the engine and engine room.. to be continued.. 😉

Wonder why they keep using a part that must be destroying the product's quality credibility. How much could they be saving, if anything? @123ignitionusa

Yes this was most helpful. Save yourself the trouble and don't read past post #8. I used copper sealer on a Victor Reinz intake/exhaust manifold gasket and wrote a 1200 word dissertation about it haha. My friend and I were making our own jalapeno vodka in those days.

Where's my .02$ in a good thread of @Reptoid Overlords. Captains EGR theory is in post #3.

Was going to add this graphic to my other post. Shows the path of the exhaust gases, up through the round hole and right over and down in to the rectangular hole.

Yes, you do not need to plug the bottom hole where the tube was. Or the other side either actually, unless you were leaving a unbroken tube attached to the exhaust. It’s just a hole through to the other side which goes to one side of the valve. The rectangle hole in the picture below is what needs to be plugged. The plates designed to cover both holes on top would work best because of how the holes and the mounting points are set up. Here’s a pic from the top with the valve, riser, and studs removed. They were really frozen together and a pita to get off. The pipe is still connected to the bottom side. Just the valve removed and plugged with carbon Sent from my iPhone using Tapatalk

I will throw my 2 cents in here too. If you are looking a spending $4k or so on Mikunis, I would go ahead and get individual throttle body EFI for that or less. It will make the same or better power, be easier to get tuned, idle properly when cold, etc

Maybe someone here can swap you one for another good part if you have something lying around? Thats a way i like to work these days..