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Need help tackling this no start again

Big thanks to @Crustacean Wagon for sending me an ignition switch! It got delivered today, but unfortunately did not solve the issue. The other day all the wires popped off my ignition switch since id removed the plastic cover so I could jump the starter terminal directly at the switch. Well, upon trying to sort them all out, the terminal end came off my yellow/white wire. From what I gather, that's just a seat belt reminder, so I can't see how that would be the main underlying issue, but it needs to be fixed regardless.

Push button start is sounding more and more attractive lol
 
Well this morning I decided to dissect my original ignition switch, just to see if there was any actual failure. Little surprise to me, but all of the contacts and everything else seemed fine inside. I sprayed it down with wd40, hit it with compressed air, and than sprayed some white lithium grease on it, wiped off the excess, and reassembled it. I then swapped it out, and tried to start it. First attempt, same as usual. Turned it off and tried again, and she sputtered. Tried again and it started. Shut it off, try again, and back to nothing. I am going to have to check out the wiring at this point. Maybe one of the bullet connecters arent making good contact with the switch, or one of the wires may be on the verge of breaking. Strange happenings either way
 
Well, I fixed the broken wire for the one circuit, but same symptoms going on. I have definitely pinned this as another bad switch.

I looked up the wiring diagram floating around here that matched my setup closest. I also dissected my original ignition switch, and was able to verify all the contacts in fact matched the diagram. With this, it was off to do some voltage drop tests at the switch itself with it still plugged in.

The first test was jumping pin 50 to pin 30 with the key in pos2. The car started as expected. Next, after studying my dissected switch and diagram, I determined that 15R (labeled as just 15 on my switches) was the terminal that should maintain power with key position 2 and the start position.

Now I decided to test voltage on that terminal, with the key in pos2 and start. In pos2, I read battery voltage. Now while cranking, it dropped to around 9-10v.

Not fully ready to condemn the switch at this point, I decided to check voltage at pin 30. Again, I saw battery voltage. While cranking, it dropped 1.2v, which is reasonable on an old car with old wiring. Battery voltage is 12.4v, and cranking dropped to 11.2.

At this point, again, I'm ready to condemn the switch. I made sure all the connectors were tight for the wires, and none of them were in bad condition at all.

One thing to note, I tried repairing my original switch, but it just isn't taking. With the switch disassembled, and the rotating cam that moves the contacts removed, I was able to clean all contacts (non looked bad by eye), and bend the fixed side of the contacts outwards to ensure good contact when the cam isn't pushing the contact open. After many failed attempts, I decided to disassemble it again, and check continuity directly from the center power part of all contacts (attached to pin 30) and the terminal plug itself. Even with the contacts physically closed, my resistance readings weren't great. I tried pressing the contact more closed, with no change. I then pressed the contact tab towards the terminal connector, and that's why I noticed a better resistance reading. It seems the switch has worn/gotten dirty where the tab of the contact actually attaches to the terminal connector where the wiring harness plugs in

To sum it up, it seems that there is a possible ignition switch failure that cannot be seen or repaired. Even if you think it's fixed, it will probably be questionable at best for how long it lasts. Not worth the trouble for how awkward it is to remove the switch.
 
Welp, the plot thickens, but does clear up some...

Got a new, Amazon MTC ignition switch. Same problem. But I did some more testing and seem to be narrowing it down some more

I ran a wire from battery positive to the ignition coil, and the car did start by key. I then started measuring voltages, and noticed my fuse 1 is showing less than 12v on either side, even though the battery is showing 14v. As the car idles and warms up, the voltage reading starts fluctuating some.

I believe I either have an issue with my fuse box itself, specifically the copper bus bars, or the blue/red wire that comes off the ignition switch. I believe this wire runs to a junction, which then splits to feed the instrument cluster, and fuse panel. My issue could be in that junction as well.

I will continue diagnostics on this, but am currently searching for a new fuse panel, as mine is toast
 
Same story, more progress, more confusion...

I got the used fuse block, and replaced mine. I landed 1 wire wrong which just so happened to be the same wire I tapped for my fuel pump relay trigger. This made it extremely easy to trace back and get corrected.

Upon fixing the misplaced wire I have the same issue, with different diagnostic results. I have a theory on the why, but not so much the how. Also worth noting, I did try one of my spare fuel pump relays with no success.

With the fuse box replaced and all the wires connected correctly, the car will still not start on its own. I have verified that still, it will start with key pos2, and jumping the starter. With it running, I noticed very much so that my lights are brighter and that the engine doesn't load up as much when turning accessories on. This alone to me made it worth the swap.

This is where the waters get muddy for me. Before, I could run a jumper wire from battery positive to coil positive and the car would fire up just by the key. This is not the case anymore. The car will crank all day with that jumper in place but will not fire.

I believe this shows that I did have multiple problems. It seems like I fixed the run circuit issue, but possibly made the other issue worse. Say both the run and start circuits were halfway compromised. Well adding the coil jumper would power the run circuit independently of the ignition switch. I believe that by fixing my voltage drop on fuse 1, that the run circuit has been restored. It's possible though, that in restoring this one by replacing the fuse panel, that I did more damage to the start circuit. Now that the start circuit is worse off it still won't start, even with the run circuit fine. Idk, just a theory there.

I plan on checking across a couple fuses for voltage drop during cranking, specifically fuses 12 and 13, as they come directly off the run circuit from the ignition switch. If they are good, I will go deeper to the terminal strip 15+ that is also powered by the same circuit under the fuse panel.

At this point I am 99% sure my issue is either with the run or start circuits. I will have to re test several things now that my symptoms have slightly changed, but I feel like I'm missing something. I feel like my issue is with the start circuit. I've been thru the run circuit pretty deep, and everything has been checking out so far. There just isn't much to the actual start circuit. Plus, the starter works just fine
 
Ok, well today I had a bit of a breakthrough. Life has been wild, and now I am in the process of moving. I'd like to be able to have this issue fixed enough to drive the car to the new house.

I decided to check some things out. As noted, the battery to coil positive jumper no longer allows the car to start with the key. Turning the key to pos2 and jumping the starter starts it every single time.

The weird thing I found today, is that when I try starting the car strictly with the key, I get absolutely no injector pulse. I was using a noid light and didn't get any flashes while turning the ignition switch from off to start and cranking.

I then verified with the key in pos2, I had 12v on both sides of the injectors.

From here, I plugged the noid light back in, turned the key to pos2, and jumped the starter. There was the injector pulses. Now I just need to track down why they aren't there with the key.

I am also halfway tempted to just rip lh2.4 out at this point, and just go ahead and install my ms3pro mini I recently bought. I am a little against this, because in the off chance the issue remains, I will have a few more variables at that point
 
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