SteveJ

I am not stepping into the middle of the block vs loop debate. There are plenty of threads on here and over at Zcar.com on that subject. As for internally regulated vs external regulator, who are you going to trust? A parts guy reading a generic list or me & the FSM & the parts manual? If you installed an internally regulated alternator when you have an external voltage regulator, your charging system will NOT function properly. Also, you should load test the battery if it got drained. By the way, the official change to an internally regulated alternator was in 78. What is the build date of your car?

1. Have you downloaded the FSM? It has directions on testing the charging system. 2. Did you test/replace the voltage regulator? Unless your car has been modified, the voltage regulator is external to the alternator. 3. You can get another heater core from Black Dragon, but you may need a new heater ©0©k as well.

I found out about another car show nearby today. I took out the 260Z and enjoyed the ride. The pictures are here: Dawsonville Car Show April 2013 | Fiddling With Z Cars If you like old Detroit iron, you'll like these pictures.

One way to test the coil: 1. Disconnect the wires from the coil. 2. Measure resistance from the positive to negative terminals. (primary) 3. Measure resistance from the center post to negative. (secondary) The resistance of the secondary side of the coil should be several thousand times more than the primary side. If it's significantly less, the secondary side of the coil is bad. The primary side should probably be about 1.5 ohms or so. If it's less than an ohm, the primary is bad. Also, post clear pictures of the rotor and the inside of the cap. If they are worn/bad, you won't have a good spark. Finally, you can download the 1980 FSM and read pages EL-24 to EL-26.

I traced the blue wire some. That circuit goes to several places. It would take some digging to be sure, but now I'm thinking it's for some feature involving the air conditioning.

However, that is only if you tap into it downstream of the flasher relay. (That's why I mentioned the power from that circuit could be intermittent.) If you tap into the blue/yellow wire, that is upstream of the flasher. That wire will have 12VDC to chassis even when the hazard lights are on. Since that is also connected to the wire that goes to the brake switch, my warning still applies. I realized in my earlier post I wrote "turn signal flasher" instead of "hazard flasher". I wish I could get the words accurately from my head to the keyboard.

Not necessarily. It is also logical that the timing is off. An inductive timing gun could tell if whether or not you have a spark and if the timing is correct. Are you sure you had the engine at TDC on the compression stroke when you inserted the oil pump? Now, when you measured either side of the coil to ground, you got 12 VDC. That sounds correct. You were doing your measurements with an inductor in the circuit.

If you use the wire off the turn signal flasher, it is not always hot. If you use the downstream wire on the hazard light, it could be intermittent. I would advise against tapping into a wire that serves an important function. It's not worth the risk to cause a short and lose that function. That is why I recommend the cigarette lighter. It is not on a switched circuit for the S30s. Of course, the good Captain found a nice alternative for the 76-78 cars as he described in another thread.

Yep, you have an 11/74 build date. This is important for you to know. For example your gas tank is more like a 75 gas tank than a 73. That means you have to look for parts such as the sender, filler, vent hoses, etc. that will work for a 75.

You can see the definition pretty well in the black, green and white Z cars from the pictures I posted here: Caffeine and Octane March 2013 | Fiddling With Z Cars. Be sure to let your browser zoom in.

I looked on the 75 wiring diagram. The wire off of the defroster fuse does not branch off for that circuit like the later 280Zs.

There is a lot of mutual respect among the frequent posters here. That is why I post here more than other boards. We also tend to be nicer about saying "search" or RTFM. I hope we helped to give you the answers you were looking for.

There's always this guide...SCC Technical Assistance Program- Sport Compact Car Web

Have you gotten your car running, yet? I have a sneaking suspicion that there are more important issues for you to attend to than trying to reduce weight. Make sure the car runs right and all of the components (especially soft hoses) are in good order.

A voltmeter will read 12VDC from a positive wire to earth. Most circuits in the Z are wired as positive, fuse, switch, load, earth. You have to make sure that switches are closed and fuses are good for measurements. For testing earth wires, you can measure resistance from the downstream side of the load to the chassis. Also, touch your leads firmly together to get an idea of the internal resistance of your meter. Subtract the internal resistance from what you measured in the wiring. If it's more that a few tenths of an ohm, then you will need to inspect the harness and the contact point between the wire and chassis. For the wiring, I think BE-4 should be close if not exact for your car (except for any mistakes made by the documentation team for Nissan). In that wiring drawing, the power for the hazard lights and brake lights come off the same fuse. The brake light circuit does not go through the hazard lights as it does on the North American 240Zs, but the turn signal power does. There is a 20A fuse in the fusebox for the brake lights/hazard lights. There is a green/yellow wire attached to that fuse. It should be the fuse on the lower left where the cover is marked STOP. From the fuse, the green/yellow wire goes to the brake light switch at the pedal, while a blue/white wire branches off to the hazard flasher. From the brake light switch, another green/yellow wire goes back to the brake lights.

Dang it. My bad. I did a crappy job of tracing it. I only followed it up to Pin 5 on the ECU and assumed that the ground when from Pin 5 to ground through the ECU chassis. Thank you for the correction.

Okay, now that you have torn up everything and gotten yourself frustrated, let's see if we can put you back on the right path. Most people monkey around with the interlock relay to try to fool it. I believe there is an easier way. The emergency switch will bypass it nicely. As a test: 1. Unplug the emergency switch from the engine harness. 2. Locate the blue wire and the yellow/black (stripe) wire. 3. Use a short length of 12 AWG wire and jumper those wires together at the plug. 4. Try starting your car. By the way, the scary part of your pictures is seeing the splicing in there. I wonder what the PO was doing. Also, it looks from your fusebox that you have a late 260Z. If you don't mind sharing, what is the build date on the VIN tag in the door jamb? I have found that Nissan moved some components around between the early and late 260Zs. If people don't know you have a late car, they may tell you to look in the wrong place for certain components.

Actually, what I should have said is that the ECU provides the ground for the fuel pump relay.

If you were in the states, I would say Ace Hardware since they have a good collection of springs.

Well, what all are you thinking of doing with the swap? The ECU controls the electric fuel pump. If you keep the electric fuel pump, you would need to add your own relay control for it since the fuel pump is triggered by the AFM in the 77. You would also have to reduce the pressure, too. If you disabled the electric pump, you would need to remove the blocking plate and add a mechanical fuel pump.

Heck, Leon. I'd just push a button as the first test with a 74. I'd be willing to bet money that the interlock is what is dropping the voltage to the solenoid, too.

Do the research first in the FSM. You will see what you should try next.

That's the one I bought. I found mine on eBay.

I bought an abrasive blaster at Tractor Supply. I just have to get around to trying it out. By the way, Blue, what did you and the good Captain find out when digging through the flattops? A friend gave me another set recently.

Welcome. Start searching on here about waking up a car that has been sitting for a while. The 74 also has a "safety feature" not on any other year Z. Search through these results to see what I mean. seatbelt interlock site:classiczcars.com - Google Search