Captain Obvious

That all sounds normal. The gauges should move off their seats when you turn the key to ON. Bench testing should be relatively easy. Only complication is that you will not be able to directly measure the resistance of the sender unit while the sender is being used in the circuit. I would suggest connecting everything up, heating the sender to temp, note the gauge reading, and then quickly disconnect the sender and measure it's resistance before it has time to change temp dramatically.

I'm not sure that is related to the issue you've been working on or not. Next time you try to start the engine from cold, pull the small B/Y wire off the starter first and turn the key to START. You should hear the fuel pump run and prime the system. I'm thinking that your first start of the day difficulty may simply be that your fuel pressure has leaked down since the last time the motor ran. And yeah... Do the longer fuel line thing and let us know how the fuel pressure looks while driving.

Confusing diagram. I think they are trying to show "this is how it looks while in use". I think you are correct in that the nomenclature for normally open and normally closed is wrong in that diagram.

Yeah, I think it's a naming problem. I've looked the diagrams over and even though they call that thing a seat belt relay, I cannot find any connection between the seat belts and that relay. The switch in the seat belt buckle only actuates the buzzer. There is no interaction with the starter at all. And the inhibitor switch is on the transmission. It is closed only when the transmission is in PARK (and probably NEUTRAL). In other words, if the transmission is in reverse or a drive gear, the starter will not crank. You have to have the trans in "P" to start the car.

There is mention of a click when the key is turned, even when the starter does not engage. Can we get some clarification of the location of that click? In the original post, it was said "I just hear a click at the starter" and then later it was described as "click heard under the passenger side relay panel". Can we narrow that down to either a) at the starter itself, or b) over by the passengers feet?

This is a no crank situation when hot, on an automatic. Other than the obvious (wires, fuses, and connectors, etc) here are the components involved: Ignition switch Ignition relay Starter relay Inhibitor switch Starter The starter and ignition switch have been replaced recently. Doesn't guarantee that it's not the problem, but hopefully unlikely.

Yup. Slight pressure and move the tumblers around. Each tumbler should click over the wall and then move to the next one. Keep doing that one wafer (tumbler) at a time and the cylinder comes out.

I don't know if the heating and cooling over the years has an effect. The change in needle location before and after the work you did is a little puzzling other than the possibility that you cleaned a bunch of connections between the two ends of the system. So do you know if your oil pressure gauge is anywhere near accurate? Ever put a mechanical gauge on it? If the oil pressure gauge IS correct, it's still puzzling. But if your oil pressure gauge is reading inaccurately high, you're back to adjusting the gauge. And... It would be good to know if you've got lower oil pressure than you thought you did.

That is correct. The lower resistance, the higher the gauge reads. So yeah... One possible explanation is that maybe with the work that has been done to the car, including cleaning connections, may result in a higher reading than before that work had been done.

I think the complication may be that the compensation section is shared by both the gauges in the housing. it's in there, but not obviously attached to the TEMP gauge. Those pics I posted above are from the fuel gauge which shares the housing with the ammeter (or voltmeter depending on the year). And since the operation(s) of the ammeter/voltmeter are very different than the other gauges (fuel/temp/oil), they do not use a compensator stage. Here's a pic of the guts for the TEMP/OIL gauge. Note that there is only one compensator stage located down by the OIL gauge section. (in the lower right). That compensator is shared between both TEMP and OIL: So the bottom line is that if you adjust the compensator, it will affect both TEMP and OIL. If you're OK with that, then that's where you should focus your effort. If you DON'T want to do that (because you like where your OIL gauge reads and don't want it to change), then yes... I'd just tweak the bimetallic strip on the TEMP gauge and call it a day.

Yeah, once you know what you are working with, it's easy to get it apart even without the correct key. Been a while since I've been into the locks and I don't remember which direction the tumbler springs push with respect to the "walls" inside the barrel, but it may be as simple as using an uncut key? If not that, then some rudimentary lock picking would be the trick.

Phoned a friend! Haha!! Glad to help.

Sorry, but I can't view that attachment. Whatever format that is, my system can't deal. Can you post a .jpg or a .pdf?

This worked great for me. Both with loosening, and then re-tightening with engine out of the car: I'm not sure if all the flywheels had these holes along the outside edge, but I used a tight fitting punch (8mm or 5/16) in the hole and then blocked rotation with a bolt threaded into the block: This may be old hat to you engine guys, but it worked great.

Well it sounds like you have narrowed the issue down to an ignition electrical issue, and not fuel. That's a big step. So it may be temperature related, but at least we know it's not (directly) related to the fuel supply. Can you post a pic of your thermostat housing?

So the unusual nature of this issue has me intrigued. I know you said you were going to have the combo switch thing rebuilt, but in the meantime, I had a question. Are you running an old style single screw mount ignition switch, or has the whole assy been replaced sometime over the years with the newer two screw style? Here's a hoovered pic of the difference. Older single screw mount on the left, newer two screw mount on the right:

Yeah, that temp gauge is a little disconcerting. Even if your logical mind knows that it's an instrumentation issue and not a real temperature issue, just looking at that thing would drive me nuts. So while you are in there, are you happy with the location of the oil pressure readings? Because if you're going to be into the guts of the gauge, that would be the opportunity to adjust the OIL as well.

I figured. But it was worth a look!

So I did a little thinking and looking and I have a theory.... This time a little less knee-jerk. If the brake light only comes on in the LOCK position, my theory is that you plugged the connector onto the back of the ignition switch 180 degrees out of position. I don't have a harness here to see if that's physically possible or if things are mechanically keyed, but if there is no key, you might have done that? I admit, it would be unlike you to do something like that, but who knows... In a flurry of hurried activity, not lining up the unpopulated connector cavity and all that? And if you did, it can cause exactly what you described.

Oh wait... Sorry, I missed that detail. The brake light is on when the key is in the OFF position!!! So all that stuff I wrote... Forget all that. It's more complicated than just a brake warning switch. So I'll shut up here and wait while @SteveJ provides some REAL help instead of the knee-jerk blather I posted above. I mean, your brake warning switch may still be screwed up, but there are some electrical gremlins at work here too.

Short answer? Because your brake failure switch is indicating a brake failure. In other words, the switch is closed. Long answer? I'll let @SteveJ work you through it! But I suspect the problem in inside the brake switch. Something like your little slidey piston is all gummed up and stuck on the "fail" position: Or maybe one of your tiny metering orifice holes is gummed shut with 50 years of gelatinized brake fluid and deteriorated rubber:

Yeah, it's always it's a little risky to go running more fuel lines all over, but I really think you need to do that. Make sure you have a good fire extinguisher with you, just in casel. In the meantime, I'll think a little about where to go next if you come back and tell us the fuel pressure numbers are just fine under load even when the engine isn't running properly.

Then, in this pic... You see the little screw? That's an adjustment screw for the gauge. Make the contacts tighter, it should read higher. Make the contacts looser, it should read lower:

First, have a look at this thread that details how the gauges work:

It's not the same. It takes a lot less fuel sitting still at 3K sitting than driving around. The load is so much lower. Try this... Sit in the driver's seat and with the engine running, push the gas pedal down until the engine is spinning at 3K. Note how little pedal it takes to do that. Way less pedal to do that than do drive around under load. Hope you can make some headway with this issue. I'm sure you're tired of dealing with it.