Captain Obvious

Thanks guys! I did consider an idiot sound as well, but I didn't think I would hear it. Windows down, exhaust singing, valves-a-clickin, and the radio playing 80's hair metal at volume 11. No way I was gonna hear a beeper. I figured that the flashing warning lamp would catch my eye even in my peripheral vision. I won't know until the spring how it looks on the road though. I'm also considered wiring it into the oil pressure as well. It would be a pretty addition at this point. I'm torn between sharing the same warning lamp for both functions though. It would certainly be easy to discern which of the two faults caused the lamp to come on, but it would sure be more glamorous to have one for each gauge.

On my last drive of this past driving season, my engine overheated. It wasn't intended to be the last drive, but unfortunately that's how things worked out. The failure was a split in one of my engine compartment coolant lines and I lost most of the coolant. I didn't know anything was wrong until it was too late. I never noticed the temp gauge creeping up and I didn't know there was any problem until I saw wisps of steam while sitting at a traffic light. And by that point, it was too late... The coolant was gone, the engine was overheated, and the temperature gauge was pegged hot. It became clear that even though I believed I scanned my gauges frequently, it wasn't good enough. I needed a solution that got my attention. With that in mind, I decided to modify the gauge to add a warning lamp in addition to the gauge needle. The "Idiot light modification." Here's the faceplate for the temp/oil gauge. There is plenty of room on the right hand side to put an indicator light. First thing is to make sure it doesn't interfere with the needle. I put a piece of tape on it and marked the needle position at full scale and then marked where I could put an LED to use as an indicator such that it wouldn't interfere with the needle. The black dot above the "0" is where the LED will go: Drill the hole in the faceplate and insert an LED from the back side: Here's the front side with the LED in place: And here's the gauge reassembled with the warning light off: Warning light on: I haven't built the final version of the driver circuit yet, but just to test the idea, here's a video of proof of concept: https://youtu.be/itjYR885iik I will take some final pics after the drive circuit is worked out and the gauge is in the car. Here's to hoping this will get my attention if I ever have problems again!!

Nice car. Wish I had the money. And beautiful collection. I got a question though... Your ad says a "'71 240Z, 1 Owner" But then you say you purchased it from the original owner. How can that be a 1 Owner car if you're already the second owner? And the next purchaser would be the third owner, right?

Yeah, Happy birthday Chuck! I think for a birthday present, you should let me take you out for a ride in the Pantara. You would have a great time, and I would be happy to suffer through it for your enjoyment.

Well I didn't trust my memory, and good thing... I took a refresher look at the docs and all that crap I said about the ignition module was incorrect. The earliest modules had the pigtail design like the one you have there. The 78 version I was thinking about doesn't have a pigtail. It has the connector built right into the module. Sorry for the noise... I should have checked first.

Good luck with the sales. I'm not looking right now, but I can help refine the merchandise a little... The voltage regulator is not stock, and is an aftermarket (solid state) unit.

Dave, Did you ever measure the resistance the sensor drops to while hot?

Are you sure yours isn't working? Just because it's rusty, doesn't mean it has failed electrically.

There is no "threshold". The current is always being pulled through the bulb filament. It's just that when the sensor RTD is cool enough, the current is so low that it won't make the bulb filament glow. The current will gradually go up as the temperature of the tank sensor increases, and at some point, you'll notice it on the bulb because the filament is glowing bright enough to see it. In other words, it will glow dimly before it glows brightly. And it happens slowly. It's an analog function, not step change.

That sensor isn't a capacitor, It's an RTD. They push the current from the fuel warning lamp through it and it heats up. If it heats up enough, the resistance drops and the current gets high enough that it makes the filament on the warning lamp glow. The trick is... When it's immersed in fuel, it won't heat up enough for that to happen. But when the fuel level is low enough and that sensor is hanging in vapor (and not immersed in liquid fuel), it heats up enough to pass higher current. High enough to light the lamp on the dash. @Dave WM did some analysis and came up with the above.

That's why I'm still using a desktop. Only issue is when I travel.

Weird. Mike's message looked fine to me all three times. Must be the Canuck having trouble with the Texas accent. I'm in the middle, so I understand both, eh?

That's what I was thinking as well. Looks just like the work that my PO did:

And to be honest... That passenger side looks too narrow. I wouldn't want any gap at all. I would want to have to squeeze that one into place as well.

I found I needed to slightly modify the driver's side poly bushing to get it to fit to the rack correctly. And even then, it was a tight fit. I had to tap it into place with a plastic mallet. Here's two pics of the reason, but there are lots of details in this thread. Pictures have been reloaded to page four: http://www.classiczcars.com/forums/topic/48621-steering-rack-disassembly-and-refurb/?page=4

That's simply awesome.

It's not 27 Ohms. It's either 270 Ohms, or 2.7 Ohms depending on the color of that third band and I can't tell from the photo if that third band is brown or gold. If I had to guess, I would say it's gold, making it a 2.7 Ohm resistor. As for the purpose... I wasn't there when they designed the thing, but (again if I had to guess), I would theorize the reason the resistor exists is to take advantage of the fact that the "hold" current for the relay magnet is lower than the "pull-in" current. The initial pull in is a straight connection to system voltage through the ignition switch, but once the relay has pulled in and the engine has started, the AFM switch wouldn't need to handle as much current to keep it closed. Conjecture, of course.

Tamo, Just wanted to say that I'm glad you got to the root of the problem and let you know that I read your post and wanted to help, but I know nothing about the CS144. I was hoping someone else here would chime in. So I'm just happy you got the help you needed, even if it wasn't from here.

I've seen that type of failure a number of times in the past on old equipment. Both on wires pulling through tabs like you had there and the solder ball on the bottom of bulbs. I suspect that even though the operating temperature isn't high enough to actually "melt" the solder, it is high enough to just slightly plasticize the consistency. I'm thinking that the constant pressure or strain combined with the plasticized hardness is enough that it very slowly creeps over the years. Sometimes resulting in a failure like you had there. I'm sure you've seen this too in other applications.

I believe that is the case as well. I think the extent of the effects is related to the grade of stainless and the temperature reached. But you're right... Nowhere to go but up, and you went way up! And even if the stainless properties are down a little, it's not like it's going to spontaneously rust overnight in that one spot. It might surface rust slowly or something like that. An occasional buff down with scotchbrite would probably be enough to keep from attracting undesired attention.

Nice work on working that trim piece. Only thing I would point out is that stainless sometimes degrades or loses it's stainless-ness when it gets hot. I'm not sure how hot it needs to be for this to happen, but I wouldn't be surprised if it's not as corrosion resistant in that area after the torch. Not that it really matters though! You didn't have much to lose, and even if it's not as good as it used to be, it's still way better than crinkled!

(Not surprisingly) great sleuthing there SteveJ! What about the root cause? Why do you think that wire came off the back of the socket? Heat? Vibration? Mechanical overstress? Something else?

This is a great site with wonderful members. Hopefully you'll be able to meet many of them in person. PS - Did you have your car at New Hope this year?

Har-dee-har-har. You funny guy. Seriously though., beautiful car, and excellent workmanship.

That better be southern sweet tea (at least that's what we call it up here). You probably just call it "tea".