SteveJ

You should be able to.

Here's my last photo of Dee from this morning. She loved looking out to see what was going on. She was a wonderful sentinel for the Amazon deliveries. It's been a tough day for the most part. Around noon I went to sit out on the front porch. Just before I went inside, I heard the raspy note of an old 4 cylinder as my neighbor took his MG out for a drive. I asked him how his drive went. He said there were no problems, and even the electric overdrive worked to his surprise. I told him that it was fed from the same relay we replaced. Anyway, he's the original owner of his 1980 MGB, and he takes pretty good care of the car. It shows you that a loving owner can overcome a lot of quality issues on a car.

That is the electronic fuel injection relay.

That merits looking at the connectors for corrosion.

No, it is not. If you want to test if the injector is getting the pulse to fire, use a noid light.

There could be corrosion at the connector for the dropping resistors for 1-4. Also where are you measuring voltage? Don't measure across the injector. Measure from one side of the injector connector to ground. When the car is running, you should see the voltage fluctuate rapidly. Also, the best way to test injector firing is with a noid light. If I don't miss my guess, I would say this one would work for you: https://www.amazon.com/OTC-6266-Noid-Lite-Bosch/dp/B0050SGHMW

This one I haven't experimented with. The only hatch seal I purchased was from Blackdragon Auto about 7 or 8 years ago.

This weekend hasn't been a great one for me. The wife and I decided a little while back that the last car ride for the last of our dogs would be tomorrow. Given all of the dogs passed relatively close together and not long after my mother-in-law has made it just that much harder. So yesterday I was cleaning up the wagon for the ride to the vet, and the neighbor came over to ask a wiring question for his MG. He described the problem(s), and I gave him some information. We also agreed for me to come over today to take a look at his car. After all, car diagnostics would get my mind off of losing my girl, even if it was only for a short time. I went over to his house and started looking at the issues. He had an aftermarket 3rd brake light that integrated into the license plate light and showed me where he used to have it wired with a vampire clamp. I asked him if he wanted the middle light to come on with the running lights or the brake lights. He said, "Both." With only one wire going to that light, I said he had to make a choice. What he didn't realize was that he didn't have it wired right before. We moved on to the next issue. When he stepped on the brake pedal, his tach needle would drop, as well as the water temp and fuel gauge. Yes, it was the work of Lucas, Prince of Darkness. With a little diagnosis with the voltmeter, I could see a significant voltage drop. Looking at the wiring diagram, it was obvious how this could happen. The same 15A fuse supplied voltage to about 2/3rds of the circuits in the car, and there were a lot of places where the wiring had junctions to split in multiple directions. I thought it might be one of the junctions corroded, but I ran one last test at the fuse box. Sure enough the voltage dropped dramatically at the fuse box when he pressed the brake pedal. A quick examination of the wiring diagram pointed toward the ignition relay. I searched online for the possible location, and we found that the original relay was replaced by a common automotive relay. I went back to my house to get tools and connectors to fix the wiring at the back and grabbed a replacement relay. I installed the new relay, and we ran another test. No issues with the tachometer or other gauges when stepping on the brake pedal. I added a couple of bullet connectors to fix the wiring in the back, and his car was ready for the road again. It felt good making it where another enthusiast could take his car out on the road. All of what I've learned at work and working on my cars pays off. Of course, it only was a matter of time before I returned home and was crying with my wife as we contemplate tomorrow. Anyway, careful diagnostics paid off well, replacing a $3 relay instead of tearing apart and replacing a bunch of wiring.

OEM pump: https://www.courtesyparts.com/oem-parts/nissan-pump-assu-fuel-17011p7211?c=cT0xNzAxMS1ZODAwMA%3D%3D

From the factory there is a sheet of plastic between the door and the door card. It basically goes around the perimeter of the door where you see the red and black line below. To replicate what the factory had, get some butyl tape like this: https://www.amazon.com/Sealant-PROMOTOR-Sealants-Installing-Windshield/dp/B095NMPNZ3 and create a border as shown above. Take a large sheet of 5 mil or thicker and adhere it to the butyl tape. Trim.

Thank you for being willing to reconsider the inhibitor switch. I had a feeling it could be your culprit after what I saw on my friend's car. Starting on page AT-49 in the FSM (page 314 of the huge PDF), you'll see the procedure for testing/adjusting the inhibitor switch.

Fuse size depends the gauge of the wire you're protecting. I recommend 10A for 14 AWG, 20A for 10 AWG or 12AWG and 7.5A for 16 AWG or 18 AWG. Don't forget about maxifuses or fusible links for the system as a whole. As I searched for vendors for wires with colored stripes, I found this place was probably about the most economical and flexible: https://www.sherco-auto.com/striped-tracer-wire.html You may be able to adapt this for fusible links: https://www.amazon.com/1J0937617D-Battery-Terminal-Volkswagen-Octavia/dp/B0863XLF6R As for current draw, let the factory fuse box be your guide to start. The fan is the highest draw, especially if you have AC. While the parking/tail light fuse is 20A, you can go to 10A and 14 AWG with LEDs. (IMHO the engineers undersized the wire in this circuit for incandescent bulbs.) The same goes for the flasher. The Common fuse is for the cigarette lighter. That can drop to 10A. I'm not positive about the draw on the wipers, but if you keep it at 20A, I would use 12 AWG instead of 14 AWG. The brake light circuit can also go to 10A with LEDs. Note: the fuse ratings I wrote are very much on the conservative side. However, I have seen enough melted fuse boxes and melted connectors that I prefer a conservative approach. As for wire sizes here is a rule of thumb. The wires for the large connectors should be 14 AWG. Use 16 AWG for the smaller connectors. On the 73 (and on through 76), Nissan started using the 9 pin connector on the headlight switch. That was a bad move. The connectors were undersized for the current of the parking lights, and that connector would melt down. For the large bullets, I would use 10 AWG. Consider trying 8 AWG for the circuits for the ammeter. Are you sticking with the ammeter or are you going to have a voltmeter instead?

So, what you need to do is test for voltage to ground at the black/yellow wire at the ignition switch while trying to start the car. This is why it can be handy to have a test lead with a clip so that can be clipped to a ground while you hold your probe on the back side of the ignition switch and turn the key...unless you have 3 arms.

I got new tires for the 260Z in preparation for ZCON. After that, I drove over to meet a couple of friends at Caffeine and Chrome. It's nice when you can get a 240Z, 260Z, and 280Z together at a meet.

There are 4 wires total. Two go to the start circuit.

By the way, you better be planning on attending ZCON.

Thank you for following up. It's good to know the resolution.

Even better price on the adapter: https://www.glowshiftdirect.com/1-8-bspt-male-to-1-8-27-npt-female-hex-thread-adapter/

The rule of thumb I heard is 10PSI per 1K RPM. Of course, without a mechanical gauge, it's difficult to know for sure. If you're worried enough about it, you could get an adapter like this: https://www.pegasusautoracing.com/productdetails.asp?RecID=11217 and add a 1/8 NPT mechanical gauge.

Here's a photo of the electronic flasher relay in my 73. You can see the ground wire I added on the 3rd terminal.

You may consider changing out your old electromechanical flasher relay with an electronic relay like this: https://www.amazon.com/gp/product/B0811GTVH2/ It has a speed adjustment that I like. The thing is that you'll have to run a ground wire to it to make it work.

I think we could make a meme of that, Alan.

Are you familiar with George Washington's axe? Someone is selling George Washington's original axe. The handle has only been replaced 5 times, and the head only 3 times. So I guess if you took the original East African Safari winner, replaced every single part & converted it to left hand drive, the video could have been using the original.

I never had tach issues with ZX ignition in my 260Z. (Same general design as the 280Z tachometer circuit.) It was modified by a PO. I eventually bypassed the ballast resistor and using a coil with similar impedance as a 280ZX coil with an E12-80 module. No problems. I'm not sure what you mean with respect to adding a resistor in addition to the one that's in the circuit.

Has your fuel pressure decreased causing a lean condition? Lean=hot