SteveJ

The gauge could be tested with the key in the ON position and engine not running. Use a potentiometer in place of the sender. If there is voltage going through the gauge, moving the potentiometer will cause the needle to move. Was the engine rebuilt? Was the sender removed/replaced? Are you sure all of the connections are correct? Do you have voltage to the gauge? How about voltage to ground at the oil pressure sender? Are the threads clean at the block and sender?

It could be. I was going off a post from one of the more respected members at Zcar.com. A little more digging revealed this size chart at Tire Rack: https://www.tirerack.com/tires/tiretech/45_conversionchart.jsp If the OP wants 15 inch wheels, the 205/60R15 should give a comparable tire size and not much speedometer error with the actual speed a little lower than the indicated speed.

You don't have to measure your tires per se. You just have to get the sizes off the sidewalls. (Note, that it has been pointed out in a different thread on this board that the wheel diameter can vary even with the "same" tire size.) Assuming that we're starting with a stock 175 R14 tire, I used 175/78R14 as the size. (Google is your friend.) You want a 15 inch wheel (There are not many good choices at Tire Rack, but if you don't mind the road noise, Advans are available.). This gives you available tire size (at Tire Rack) for 15 inch wheels: https://www.tirerack.com/tires/sizes/results.jsp?diameter=15

What size tires did you mount, and what is the size of the spare? There are tire size calculators that can help you figure the engine speed.

I used some Griots glass polishing compound on my 260Z windshield. It's very badly pitted and has some deep windshield wiper scrapes. It was a "it couldn't hurt" effort, and I couldn't see any difference for better or worse. Basically, from what I understand, most retail type glass polishing products are for extremely light scratches. If you can hook your fingernail on the scratch, it's too deep.

Been there, done that, have the marks on my cowl to prove it.

I haven't tried the conversion to a 260Z or 280Z distributor. I went with the ZX conversion in my 73. A PO did the conversion in my 74. The 260Z and 280Z used a transistor ignition unit (TIU) to control the spark. You would to need to figure out how to install a TIU into the car. Another alternative would be to use a GM HEI to trigger the spark. There is information online (including this forum) from people who have converted their cars to use an HEI module. I cannot say what would happen to your tachometer with either conversion. It may require figuring out how to adapt a 260Z or 280Z tach into your wiring.

Did you clean & lube the mechanical link before installing?

Randy Jaffe will be there with John Morton driving his BRE car. Rob Fuller and his crew from the Z Car Garage will be supporting. Glenn Chiou will be driving the FAR Z. Larry Cooper will be there, too. I don't think any are members here. If I wasn't working on ZCON, I would be there.

I don't think the people at Rockauto were trying to misrepresent the part. They just follow the compatibility charts provided by their suppliers. I looked at the information provided on the SMP and Beck-Arnley parts listed on Rock Auto. They list a parts number cross-reference that has many part numbers that line up to Nissan part numbering. I tried looking up the part number on Carpartsmanual.com, but I couldn't find it easily. I then put in the Nissan style part numbers into CourtesyParts.com. Here are the results (all of the positive hits came up with an oil pressure sender): 25070-80W00 300ZX 25070-55S00 200SX 25070-55S60 200SX 25070-N7600 No results 25070-P7100 300ZX 25250-S6000 300ZX 25250-S6001 720 25070-P8000 300ZX 25070-P8100 300ZX 25070-P9700 300ZX 25250-N7600 300ZX 25240-89908 No results So did Nissan use the same part with different numbers, or did Beck-Arnley and SMP take too many liberties in their cross-referencing? I went to the SMP catalog and searched for 1978 280Z parts. It lists a "Switch - Oil Pressure Gauge" with the same part number listed in the Rockauto catalog. For applications of this part, here is the compatibility list: Nissan 200SX (83-80) Nissan 280Z (78) Nissan 280ZX (83-79) Nissan 300ZX (84) Nissan 620 (79) Nissan 720 (85-80) Nissan 810 (81-78) Nissan Maxima (84-82) Beck-Arnley has a similar applications list in its catalog.

I'm not sure why you think it's complicated. The electric fuel pump has 3 switches. The first is the ignition switch. The second is a normally open contact on a relay. That relay coil is energized when the alternator is turning fast enough. (Note the voltage for that coil comes from the yellow wire between the alternator and voltage regulator. If you swap to an internally regulated alternator, you will remove the coil voltage from this circuit, and the fuel pump will never get voltage.) The last switch is a normally closed contact on a relay that opens up when you are cranking the engine. Diagnostics go like this: Turn the key to the ON position. Use a voltmeter or test light to verify you have voltage (to ground) on the black/white wire on Relay 1. (It's the 4 pin connector.) If this test fails, find the break in the wire. Start the car. Use a voltmeter or test light to verify you have voltage (to ground) on the green/white wire on Relay 1. If this test fails, you need to replace Relay 1. (This will require substituting a modern relay.) Use a voltmeter or test light to verify you have voltage (to ground) on the green/white wire on Relay 2. (It's the 6 pin connector.) If this test fails, find the break in the wire. Use a voltmeter or test light to verify you have voltage (to ground) on the black/white wire on Relay 2. If this test fails, you need to replace Relay 2. (This will require substituting a modern relay.)

No, I don't have those.

I bought a bunch of headlight connectors & shells a year or two ago.

They are talking about another member here who lives in Georgia. She damaged her car a little while back and has been trying to source the bumper ends. Seeing that you now have a large stock of cars/parts, they are probably thinking that you might be a source for the bumper parts for her.

So, there should be a switch near/on the brake handle with a yellow/blue wire running to it. As you lift the handle, it grounds the wire to the chassis.

http://www.pure-gas.org

So why do you want to go backwards to SUs from the fuel injection?

I probably have what he needs. I'm just trying to establish gender. ;)

What year? By the way, go into your settings and create a signature with the year of your car(s) in it. That way people have a better idea of how to help you.

Just to make sure, you're looking for the female connector, correct?

I am thinking it's for the turn signals, however, I'm not 100%. There shouldn't be a blue/white wire on that connector. The blue/white should be for the wipers. Did someone do some creative wiring in the past?

Post photos that show the wires, connectors, and relative location clearly.

That filter looks NASTY! I would agree with your suspicion that there is junk in the tank. As far as the AC goes, am I missing something here? I didn't see a compressor or AC lines in your video.

I haven't noticed any adverse handling issues during the drives up in the mountains here.

Irrelevant. That wire is before the fuse. What you're looking for is a problem between the fuse and the light bulbs.