SteveJ

One of the functions of the AFM is to cut power to the coil on the fuel pump relay when the engine isn't running. If you replace the AFM, what are you going to do to compensate for that signal?

Jim Frederick's chop-top 240Z was featured on NPoCP at Jalopnik today: For $15,000, This Fairlady Will Let You Take Her Top Off So far, Crack Pipe is winning the vote.

Why not just use the wiring diagram from the service manual itself? XenonS30

If I can find it (and have time and can remember to look), I have the added wiring harness that was used for the electric fuel pump. I can take a picture of it so you can see if you have one in your engine bay.

That is for an early Z. There are differences between that one and the wiring for a 73.

See, all I had to do was mention BGM and he appears. He is mystical. He is...Black Gold.

Does your 73 have the Nissan factory-designed electric fuel pump retrofit? That could account for some of the wiring differences you are finding.

Did you point the Diode the right way? If not, the alternator won't see the battery voltage.

Contact Black Gold Man. While he's a ZX kind of guy, think about looking at your engagement pictures and seeing... Black Gold

You may want to work on your search skills. 1975 Pontiac Service Manual

Ethanol-free gas stations in the U.S. and Canada

The wire is melting due to too much current. With no pictures, meter readings etc., it is difficult to diagnose the problem. It would not be due to the wires going from the battery to the starter. What is your ammeter reading when you're driving the car? How old is the battery? Maybe you should try the plug that MSA offers: Motorsport! Alternator Upgrade Adaptor, 70-73 240Z - The Z Store! Nissan-Datsun 240Z-260Z-280Z-280ZX-300ZX(Z31/Z32)-350Z-370Z Parts (Gee, this link looks familiar. )

Yes, 40 year old wires can be fragile. For the parking light circuit, you can reduce the current loading by switching bulbs over to LEDs. Here is a thread with more information: http://www.classiczcars.com/forums/electrical-s30/40600-sold-leds.html

They are available through MSA: Motorsport! Alternator Upgrade Adaptor, 70-73 240Z - The Z Store! Nissan-Datsun 240Z-260Z-280Z-280ZX-300ZX(Z31/Z32)-350Z-370Z Parts.

The entire switch can be purchased. Beck Arnley 201-1179 Key, Lock And Ignition Switch Assembly : Amazon.com : Automotive Something tells me that there is something worn in the body of the switch that allows the key to move the switch too far.

When you say you replaced the switch, did you replace the entire assembly or just the back part?

If safety is your primary concern, get a late model car. If you want a hobby car to turn a wrench on, a 70-78 Z car is a nice choice. The car has been sitting for 10 years, and who knows if it was neglected before that. Soft hoses are probably rotten. The brake calipers and wheel cylinders could be full of rust. The suspension bushings are probably gone. The steering rack could be worn out. The fuel lines could be leaking. The weatherstripping may be rotten or gone letting carbon monoxide into the cabin. There could be enough rust on the car that it would crush like an empty beer can. When I bought my 260Z, the previous owner had different size brake pads on the left and right, and there was only 1 bolt holding the driveshaft to the differential. Scary, ain't it. With an old car, defensive driving and careful maintenance are about the only ways to protect yourself, short of installing a roll cage, fuel cell, fixed back racing seats, and 4 or 5 point harnesses. (Your fiance would LOVE having to put on a 5 point harness when she's wearing a dress.)

You are correct. You don't need the 87a terminal. I usually remove the wire from the base if that is the case. It is a challenge to find SPST relays. I'm not sure why. I'm not surprised about the green/black wire being hot. the connector had melted on my headlight switch from that. Check the sockets in the parking lights, especially the ones on the sides. You are likely to find some corrosion in them. Cleaning out corrosion can prevent it from completing a relatively low resistance path. Dave Irwin's relay harness (sold through Motorsport Auto) can protect your switch. As I have documented elsewhere here, LED bulbs greatly reduced the load on the circuit, too.

Yes, my bad. For the relay I linked, the green wire would go to both the 85 and 87 pins. The yellow goes to 86 and the blue goes to 30. Now all is right with the force.

These are all on the same circuit, controlled by the same switch, and powered through the same fuse. Check the headlight switch and work your way back through all of the connectors. Download this to get more information on the connectors in the circuit. This makes me think that the problem with the rear turn signals is at the turn signal switch. Based on what else you said, it sounds like you need to find someone who knows automotive electrical systems.

Actually, the drawing tells you a lot. You just don't understand the language. Don't worry. I speak electrical. You can replace the missing relay with a standard automotive relay. You will just need to replace the connector in your electrical harness. A relay such as this has contacts with a high enough rating to work for you. You will need to splice a relay base onto your wiring harness. First, figure out which blue wire is on the ACC fuse and which is on the A1 fuse. These should be in the fuse box shown on page AC-35. The blue wire on the ACC fuse goes to the 85 terminal on the relay. You need to run a wire from the 86 terminal to ground. The blue wire from the A1 fuse would go to the 87 terminal on the relay. The green wire goes to the 30 terminal on the relay. If you are not comfortable with doing your own electrical work, contact Guy, aka Diseazed on this board. He lives in the Richmond area and could probably point you to a good electrical person. For more information on relays, I wrote a brief primer. Relays Simplified | Fiddling With Z Cars

The mechanic is correct that another relay could be substituted provided it has the correct rating. Is this a stock or aftermarket A/C system? Can you post a picture of the relay and the socket?

Look at the links on my tech tips site. You'll find plenty of vendors to get the parts you need.

I had a file of that about 12 years ago. I wonder if I can find it again.

Well, (edit) many parts descriptions are way off since few (edit) of the parts listed would work on a 280ZX.