Has anyone else tried the MSD Atomic EFI? I installed one and it works fine when the car is cold or warmed up, but as the car gets to operatng temperature, it runs erratic, stalls and then won't restart. No fault codes on the handheld but it shows no RPM on the display screen when cranking which means the injectors are shut off. The unit takes it's rpm signal from a white wire connected to the neg side of the coil. What would cause it to lose it's signal? When I crank it with the key on and coil wire off and near ground, it has spark so I don't think the coil or ignition is to blame.
Once the car has cooled down for about 1/2 hour it will show an rpm signal on the display and fire up.

Was embarrasing and dangerous when it quit in traffic!!!!

MSD tech line leaves a lot to be desired too.

What is your fuel pressure? Needs to see pressure before it will fire the injectors. What is the IAC set at when it was running?
Bad Coil? What ignition are you using?

I think the question should be are you still getting spark?

bad coil? wouldn't be the first time one got too hot to run and would work again when it cooled off.

Fuel pressure is always good. 55 psi with a return and regulator.
IAC is 0
The spark is always there. I've tried 3 different ecus and still spark. So I've ruled that out.
The coil is a brand new Mopar restoration from Chrysler.
Chrysler electronic ignition with 4 post ballast. Wiring harness is a brand new B body with electronic ignition from Year One.
The MSD display shows no rpm signal but no other faults. 1/2 hour later it starts right up.

could it have to do with using the ballast resistor? possibly its getting hot and causing enough voltage drop to the coil that its not getting a hot enough signal to the injection ecm? Don't know anything about that system just spit ballin. after that I would be leaning towards the injection ecm itself.

No offense BUT wouldn't you be better off posting on the Atomic EFI forum?

Sounds like a typical bad coil.
Did you try posting a question about it on the Atomic Forum?

Are you running a return system? Or no return?

Have you checked the reluctor gap inside your distributor? I had this problem once, for some reason too wide a gap would cause the engine to quit once it got good and warm like after a 1/2 hr. Also had the same problem with a dying coil, would run for like 1/2 hr before the engine would die until it cooled down. I know you say you're getting spark when you check it, but perhaps you're only getting an erratic or inconsistent spark that the efi computer doesn't recognize. Worth checking out anyway. I can't think of anything else that would cause you to lose the spark signal to the efi computer.

All good advice guys. I'll check out the reluctor gap and try a different coil and ballast resistor

it does sound like the EFI computer can't read the signal because it might be getting weaker at it heats up.

Thanks everyone. Once I get it sorted out I'll post the results.

It's all good Guys.

I didn't even know this system existed until I read it on here.

Of all the hokey, complicated and expensive EFI systems that are on the market it's nice to see this setup out there. If we can troubleshoot it, then that's a selling point I consider: User-Friendly.

Here is a link to the Atomic forum. I have the Atomic system, but I did not experience any problems like yours.
http://www.atomicefi.com/forum.aspx?g=topics&f=12884901886

I don't think it's a problem with Atomic EFI actually. I think the voltage at the coil is the problem. I haven't had a chance look at it yet but I am suspecting the coil or ballast resistor now.
As for the EFI, it was simple to install, and seems high quality.

I did try to get on the MSD Atomc forum but have no access to a computer these days and the forum won't let me post from a smartphone for some reason.

I called MSD tech line and explained the symptoms. They said check the reluctor gap too and said Chrysler electronic distributors have a notoriously low signal. So I pulled the distributor cap off and see the reluctor gap was about 1/8" wide!!!!!!
So I've adjusted it way tighter and I will see if the problem occurs today.

So after a good long test drive I think the problem is solved! Just needed the reluctor gap adjusted. I didnt think to look at it since it was a brand new distributor and had been dyno run.
Goes to show you can't assume anything.

Neat looking system. Does this system have its roots based on the system that came out about 7 years ago? That system resembled a typical Holly carb. The other systems on the market like Megasquirt do indeed look intimidating for the do it yourselfer.