No clue, please help

[Aeronet]

'73 Charger, 400, Thermoquad, 727, factory electronic ignition.
I start car and drive to work. After work I start car and drive home. On the way home I stop at store, park car, shut it off. I come out of store and car won't start.
The drive to work is ~20 mikes of mostly highway and takes about 30 minutes and I'm stopping after I've driven nearly to my house.
I've owned this car for twenty years and it has never done this. It's not the ECU or the coil (I've used two different ECUs and three different coils all of which are known good). I changed both of those components and it still won't start. After a couple of hours the car will finally fire up.
Anybody know what could cause this? I sure don't.

 

[Durandal25]

Ground.....it’s always the ground . Same issue on bee

 

[Durandal25]

Check the negative, and the one from the intake to the firewall

 

[Builderguy]

Need a little more than "Won't start"

Does it crank and not fire or does it do the big nothing?

 

[Aeronet]

Ok. Thanks. I will. The car did sit for awhile and when I drove I just drove around town. Maybe the firewall ground got a little rust?

 

[MarPar]

Lemme shout from the stands...

 

[Aeronet]

Need a little more than "Won't start"

Does it crank and not fire or does it do the big nothing?

Cranks, no start.

 

[Aeronet]

I did change it ( ballast resistor). I have two others. Next time I'll try that first.

 

[khryslerkid]

"Won't start" can mean different things to different people.

It cranks over but doesn't start (fire off) ?

Doesn't crank, the starter isn't turning ?

No power, nothing, turn the key and nothing happens? (No interior light, headlights, horn ect.)

Which symptom do you have?

 

[Aeronet]

"Won't start" can mean different things to different people.

It cranks over but doesn't start (fire off) ?

Doesn't crank, the starter isn't turning ?

No power, nothing, turn the key and nothing happens? (No interior light, headlights, horn ect.)

Which symptom do you have?

Cranks and cranks and no fire. Still have lights, etc.

 

[Aeronet]

Lemme shout from the stands...

View attachment 936177

Can a ballast resistor heat up and fail, but then cool down and be fine?

 

[Builderguy]

Are you running a Mallory distributor by chance?

 

[Aeronet]

Ground.....it’s always the ground . Same issue on bee

What issue did you have and what solved it it?

 

[Moparnocar]

Is it heat soaking? If you floor it, will it start? I've never owned a thermoquad, but I'm sure the new fuel can still boil off in it. Or vapor lock

 

[Aeronet]

Are you running a Mallory distributor by chance?

No, factory Chrysler unit. It's been in the car since '00 when I first got it running.

 

[MarPar]

Can a ballast resistor heat up and fail, but then cool down and be fine?

IIRC, no. If it gets hot, it's done. But if it's getting hot, there is something else wrong, imho.

 

[Aeronet]

Is it heat soaking? If you floor it, will it start? I've never owned a thermoquad, but I'm sure the new fuel can still boil off in it. Or vapor lock

No. I tried flooring it and it didn't work. In the past the car fired immediately once warm. I used this carb in August and while running A/C. I did rebuild it last summer. I used regular epoxy on the little wells (can't remember term at moment).

 

[Aeronet]

IIRC, no. If it gets hot, it's done. But if it's getting hot, there is something else wrong, imho.

It gets hot in that engine compartment. Could the distributor pickup get hot and fail and then cool down and be good?

 

[Aeronet]

IIRC, no. If it gets hot, it's done. But if it's getting hot, there is something else wrong, imho.

I did check the ballast resistor today when the car did this again. Ballast was not hot.

 

[MarPar]

I did check the ballast resistor today when the car did this again. Ballast was not hot.