SteveJ

If said you saw a voltmeter in that video I linked, you need to go look again. I never installed a voltmeter in my car.

Well, since you're not concerned about stock...

It's in my neck of the woods, too.

Yep, I was pretty sure he would be replacing the sending unit with that much difference.

I would say the resistance reading is higher than I would expect. At least now you know you aren't just throwing parts at the problem.

What scale did you have your meter set on?

It's easy to f#@k up an AFM.

Another 1st Sunday of the month with great weather meant the Zs showed up again.

It was too windy yesterday for me to sit and let the car come up to temperature. I was driving it today, so I did before and after photos. The interesting thing is the narrow band in resistance between stone cold and operating temperature. Cold: Operating temperature (from a very nice drive today)

That's to drain off the extra electrons so they don't fill up the starter.

I can probably shoot a demonstration video of the sender tomorrow to give you something to compare readings to. I believe you're familiar with my YouTube channel.

That sounds like an intermittent connection. On my 240Z I thought I had a sender going bad. I replaced it, and the gauge registered for a little while before it stopped working again. I checked the connector, and it was just barely attached to the wire. I put on a new female bullet, and I've had no problems since. Did you take a resistance measurement from the sending unit to ground like I suggested?

A diode won't help you. Here's the issue: something is limiting current flow, such as a dirty fusible link, corrosion at the ignition switch, or poor contacts in the ignition switch. What ever the cause, the limits on the current flow result in lower voltage in the ignition circuit. Think if a partially blocked pipe. Water can still flow through it, but as you open more valves downstream of the blockage, the pressure (voltage) drops. If you put the year of your car in your posts (or in your signature), I can give specific diagnostics. There's a good chance one of your future best friends will be a Dremel with a wire brush to knock off corrosion.

You didn't use the ignition circuit to power the fan, did you?

The thermostat has a weep hole for some coolant to pass before the t-stat opens. Here's the 280Z t-stat housing. This drawing shows the EFI sensors and switch. I think I found what you are referring to. Here are most of the part numbers in that drawing: No, I didn't see any mention of this in the 75, 76, or 78 FSM.

There is no coolant bypass. When the watercock valve is closed, it is deadheaded.

It's just for the "key in" buzzer. I'm not sure what all you would have to disassemble to get to where it goes.

Someone reported these as being dimmable. I can't remember if it was @cgsheen1 https://www.amazon.com/gp/product/B0B9MGSX7K Update: It was @kully 560 who used them.

I'm up in the northeast corner of Forsyth County near Lake Lanier.

Love it! I hit 30 years of Z ownership in June.

Maybe my message got him looking. I'm glad you're getting taken care of.

I just reached out to Hung Vu on FB. He's having supply chain issues with the supplier.

You will need a decent multimeter to diagnose this problem. Here is what I suggest doing. Put your meter on resistance. Take a reading from the terminal on the sending unit (with the wire unplugged) to ground. I like using a stud on the driver's side strut as the grounding point. Do this with the engine stone cold. Get the car up to temperature. Take another resistance reading on the sending unit. If the resistance hasn't dropped significantly, either you are doing it wrong, or the sender is bad. With the wire to the sending unit still off, turn the key to ON. Put your meter on 1 Amp current. (10 A if 1 A isn't available. Put the negative lead on the sending unit. Put the positive lead on the wire that goes to the sending unit. The current reading should be dancing. (If you look through my videos on YouTube, you'll see a demonstration of this. My channel name is MyZCarLife.) If the current reading isn't dancing, you need to inspect your wiring. Do these steps first and report back. Then I can write up the rest. Please create a signature with the year of your car. That way I can provide instructions specific to the year of your car for the next phase if necessary. (I know it's in the subject line, but sometimes I have a lot of tabs open and can't see the subject.)

Well, if you're going to be that way, try this page. https://easternbeaver.com/Main/Elec__Products/Connectors/Sealed/YPC/ypc.html

I believe it's this one. http://www.vintageconnections.com/Products/Detail/80