chaseincats

This is the Amazon product I used - the cap and rotor came as a set so you'd think they would function together properly: link here I never thought to check until now, but since the cap/rotor I pulled off early in this thread was also (very) chewed up, it makes me curious what is going on especially since there is no play in the shaft like you saw in the video. The distributor is facing the right way as the car runs very well outside of this weird issue. Here is a pic of the rotor installed and then one of cap installed (with the rotor inside of course). The cap fits flush and snugly on the distributor with both of the spring clips clipped. The car is a 1978. I hope these help:

I made a video here - this might help

@Zed Head well scratch all of that - looks like you're right again. i really should just stop coming up with my own ideas and listen to you people. The car began its hard starting nonsense again today so I pulled off the brand new cap and yep - the brand new cap is getting ground down by the brand new rotor. I confirmed this by pulling off the rotor, writing on it with a marker, putting the cap back on and turning it on for ~20 seconds. pull the cap off and yep, the marker's ink worn off in the same spot. The distributor's shaft has 0 play in it. I could just grind the rotor down with a dremmel, but I mean cmon.

fair but the tank was being vented through essentially the gas cap and the carbon canister. one interesting thing to note is 2-3 minutes after putting the cap on with the car sitting off in the garage, i heard what sounded like bubbles/fuel moving/fuel splatting on the ground/etc. i ran to the back of the car and there was nothing on the ground. after a thorough inspection of everything I was going to pull the car out of the garage, I turned the key and the car started up on the second crank which has never happened in the decade+ that I've owned it. it also sounded like the starter was somehow turning faster too. I did some research and it said with the cap on, the tank was now a sealed system which pushed air that was in the lines up into the evap tank and the starter was spinning faster because the it was no longer pulling the engine against a vacuum.

Update: the problem was the gas cap. The cap I had was leaking vapors and not allowing the tank to pressurize as a result, after the car sat for a bit and all the pressure in the tank bled out, there was nothing holding the fuel back from flowing back to the tank. I got a new cap and all good now.

This ended up actually being unrelated and fixed a few months back: The car shut off after I hit a bump. I discovered if I knocked on the black relay box/bracket under the hood, the car would die. I unbolted the bracket and one of the relays (I don't recall which one) had something loose in it because any slight wobble and the engine would stumble - and a light flick would kill it. I opened the relay itself and there was something loose (I don't remember what) - I bent whatever it was back into place and now I can smack the hell out of the bracket without the engine blinking an eye. I also found out that the connectors that went from the engine harness to the ECU temp sensors were weak to the point where if I (also) wobble those, the engine would stumble and die. Basically I went on a SHAKE EVERYTHING tour of the engine bay and we're all good now.

I just checked and the TIU is still there AND is plugged in which is interesting

Funny story about this - the pully tensioner bearing squeaks regardless of if I change it or not - so I just stopped changing it and live with the squeak. My friend was over and we noticed if you spray it with silicon lubricant it quiets down. That is not important to the story. What is important to the story is after spraying the tensioner bearing with the spray can, he tapped it accidentally on the metal ignition coil and did indeed receive a 'violent shock'.

Interesting - thanks for this. When using this, does that mean the 'transistor ignition unit' in the passenger foot well is disabled and that box I took a picture of is running instead? I have no idea what the point of this thing is but I've never messed with it since the car runs.

The coil is connected this this box:

The wire is as seated as it can be and it's always done that since I've had the car regardless of new wires, new cap, new rotor, new plugs, etc. The Jacob Electronic unit is the only thing that is the constant. I believe the toggle switch was a kill switch but I don't recall - I never touched it.

As a side note, ever since I've had the car - which is going on a decade - it has chewed up/melted the port on the cap where the wire that comes from the coil plugs in. I have a Jacobs Electrics coil on there, could that be why? Pics below:

Glad to hear the cap might be where this issue is coming from instead of the transistor ignition unit or the ecu but I wonder how those teeth got so chewed up

I don't drive it enough for it to be sizable and the cap is a couple years old so MAYBE 1000?

Ok ill grab a new cap/rotor combo

I popped off my cap/rotor today because i got a couple of those small/quick jerks where it like the engine shuts off a cylinder for a second. The teeth look like they're being chewed up and there's scratches on the inside sides of the cap (circled). Could that be it? Also, how does this even happen? Can the car still run well if the rotor isn't pressed fully down? I remember this happened when I started driving the car habitually after sitting for a while but this behavior eventually went away. Here's some images with the problems I noticed circled:

The valve is new(ish) and I know it's not flooding the engine because when I trigger it manually (i have a switch in the cabin) the engine fires right up.

Coincidentally I replaced it maybe 6 months ago because it was leaking and original

The strange thing is it has the hard starting issue if I prime it, but it doesn't have the hard starting issue when I used the clamp to keep fuel in the rail. That didn't make sense to me since its essentially doing the same thing...

Fair point - will do

There shouldn't be an issue with the pump since it is brand new but couldn't hurt. Could you take a picture of how you have the hose routed to avoid the potential of it rubbing on the axel?

Right, I was curious if the FPR was letting fuel bleed past and into the tank, so I clamped the line that comes after the FPR in the same way as I tested to see if the car was losing pressure after the fuel pump, so I clamped the line that heads into the fuel rail

The FPR is good. I tested it by clamping off the return line (the hose that comes out of the lower outlet of the fuel rail) and let it sit overnight. The car had the hard start issue. I then instead clamped off the inlet hose (the one coming from the fuel pump) and the next morning the car started without issue. That is how I determined how to test which item is not holding fuel/fuel pressure when shut off.

I remember the ideal way I saw was to loop the hose up and over one of the metal things under the car (working on this was so long ago i don't remember what 'metal thing' it was) but that ended up making the tank line angle like this: /-\ which hindered fuel flow. Could you take a picture of how you have yours routed?

The wrong fittings meaning the clamps on each hose? This is the setup that I've had on there for a decade so it's odd its having this issue now that I changed to new hoses.