SteveJ

That's the ground wire for the VR. It shouldn't be carrying a lot of current to begin with. I have a replacement in the box that I bought from BlackDragon (Victoria British) a long time ago. Let me see if I can find it. Meanwhile, I suggest you test resistance to ground on the engine side of the harness where that wire connected to. Frankly what catches my eye is that loose green wire.

The wiring work is getting inspected, and I've barely even started.

On the other hand, I did use some of the parts in the hardware kit. I can't remember which parts because it was many years ago.

Yep, it's the ECU. When you have to resort to percussive maintenance, it's pretty much ready for a restoration.

Jump 1 to 5 & 2 to 3. I even found a source for the 6 terminal connectors to make a nice looking plug for the VR connector.

Solenoid was the wrong term. I apologize. That's what I get from going by memory. Look in the EC section of the FSM. On the bottom right of EC-10, you get a very vague description of the throttle opener. That is what prevents the throttle from slamming shut when you are off the gas quickly. Basically, it uses the engine vacuum to keep the butterflies open some to prevent an overly rich condition. When the 280Z came out, the system that car used is known as the BCDD or boost controlled deceleration device.

But is the solenoid working?

Does your car still have the solenoid to keep the throttle from slamming shut when you get off the gas? If it doesn't, then you have a sudden rich condition when you lift off the gas.

There are easier ways to find that 10mm socket you dropped.

Vredestein: https://www.vredestein.com/classic-tires/products/990-SPRINT-CLASSIC/

They were on both sides. You can see the other side here: https://www.brelegacy.com/mm5/merchant.mvc?Screen=PROD&Store_Code=B&Product_Code=photo240z_image008&Category_Code=brearchivephotos240zs And here is the passenger side of the 3 car: https://www.brelegacy.com/mm5/merchant.mvc?Screen=PROD&Store_Code=B&Product_Code=bre2_240_3_ocraceway_002&Category_Code=brearchivephotos240zs

Search for LED list. The updates from October of last year are the latest. Vendors on Amazon change their product lines, so some searching may be required. Auxito for the bulbs Koito via Toyota for the H4 housings or Hella.

And THAT is a good reason to consider their product.

By the way, if you go with the brand bulbs I recommend, they are polarity independent so you don't have to incorporate relays into the headlight circuit.

No. I have done the H4 with LED bulbs MANY times without issue. @HusseinHolland did the same thing with the parts I recommended. No problems.

Why? H4 housings with H4 LED bulbs work fine in stock buckets.

The hole on the thermostat is threaded as BSPP. I don't think ACE will have that.

If it was easy, why would it be worth doing?

What do you mean? The N33 (73) and N36 (74) manifolds will accept round top SU carburetors. Those are the manifolds on my cars, and they both have SU carb bodies attached to them.

You mean like this?

Oh come on, be brave!

This may be more helpful in answering your question: https://www.zcar.com/threads/n42-block.33669/

While this doesn't directly answer your question, it's still a good (and short) read:

Nope. No drain screw, at least not on the set I had handy. There was a heat shield on the bottom. The shield covered this: Still no signs of a drain screw, so I took off the bottom of the float bowl. Nice and gunky! Here's a side view of the floats. And the float bowl chamber. No penetrations on the sides that I could see. I'm thinking that valve is TOAST. Anyway, when putting it back together, note that 1 screw is shorter than the rest. The short screw goes where there is an indentation on the bottom cover. Don't dismantle unless you have a new float bowl gasket on hand. And don't buy the cheapest kit since that kit does not have as many gaskets. (2 needed) https://www.rockauto.com/en/catalog/nissan,1973,240z,2.4l+l6,1209170,fuel+&+air,carburetor+repair+kit,5964