Quits when it gets hot…

[Big_John]

I think I’ll replace the whole electronic ignition package to start. Pretty cheap kit and would hopefully eliminate most of the things it could be.

New isn't necessarily better.

If that's an older conversion, with a Chrysler built distributor, replacing it with the offshore version is a big step down.... and that's all you can buy new these days. Pretty much the only thing that would go wrong in the distributor is the pickup.

Now, if you want to throw parts at it, an ECU (the box) is a good place to start. I usually don't like to see parts replaced to diagnose, but the ECU is a really good spare to carry if that turns out not to be the issue. There are some diagnostics you can do on the pickup, but again, intermittent problems can be tough and that's another spare to carry.

 

[413]

swap in a points distributor then you bypass all the potential problems to see how it runs.

dont sand off the paint under your electronic boxes for grounding. That’s not where the grounding occurs. Have you EVER seen a factory built car sand off the paint under anyngrounded electrical parts? They never did it.

All of our original voltage regulators are grounded to the body and they have full paint under there From the factory. They built millions of cars they made it through warranty with no problems.

 

[75LandYacht]

Since the last owner was also on here, I took a quick look and didn't see where he had any ignition problems like this. It was a Mopar electronic ignition that was added, I did find that. Probably not a bad idea to look over his threads.
challenger

So, with that in mind, I'd be suspicious of the ignition box or the pickup coil being the problem, especially the pickup coil. Since it's intermittent, it's going to be tough to diagnose.

That’s what I told him too, Pick up coil in the Dizzy.

 

[thethee]

New isn't necessarily better.

If that's an older conversion, with a Chrysler built distributor, replacing it with the offshore version is a big step down.... and that's all you can buy new these days. Pretty much the only thing that would go wrong in the distributor is the pickup.

Now, if you want to throw parts at it, an ECU (the box) is a good place to start. I usually don't like to see parts replaced to diagnose, but the ECU is a really good spare to carry if that turns out not to be the issue. There are some diagnostics you can do on the pickup, but again, intermittent problems can be tough and that's another spare to carry.

+1 on the ECU.

A year ago or so I had very similar problems and tested all I could before buying new parts. Swapped in a Standard Motor LX-101 and all was good again. It's a pretty cheap and cheerful ECU, rockauto carries them

 

[Chopperdriver]

For me it’s easier to eliminate old parts that I don’t know the history of. Especially if I don’t know if they were put in correctly or if they were new to begin with. A couple of hundred bucks is just a good nights sleep.

 

[CBODY67]

For me it’s easier to eliminate old parts that I don’t know the history of. Especially if I don’t know if they were put in correctly or if they were new to begin with. A couple of hundred bucks is just a good nights sleep.

Ok, so go into Rick Ehrenberg's eBay website and get some good stuff from a known Chrysler guy who knows what "good" is. Or possibly the Mancini Racing website, too. Rather than just going down to the local big box auto supply to buy psrts.

Certainly, the factory did not sand under the ground connection holes, BUT there is a reason that many of the sheet metal screws holding those things to the car had star lock washers under the flange-head sheet metal bolts.

In this weather, be sure to remain hydrated as you work, too.

CBODY67

 

[413]

Yes the mounting bolt/screw does the grounding, threads inmthe body and the bolt head on the part. Later they added barbs on the washers to help out. Same with taillight nuts. Your taillights ground through the mounting nuts, they have gaskets where they touch the body.

 

[1970FuryConv]

I used Rick Ehrenberg for the ECU for my 1973 Dodge Monaco. Its problem was that it would not start when it was cold but would start when it was hot. My first ECU was a replacement ECU of questionable quality. Rick's 4-pin ECU cured the problem instantly, without any extra grounding.

Checked his eBay store, Ricks – Mopars, he's away until June 19

 

[MONC440]

Could it be wired incorrectly with the start wire going to the coil and the ballast wire. I think this will overheat the coil and cause problems.

 

[75LandYacht]

Here Here on Rick Ehrenburg!! Purchased many items from him for my 77 New Yorker, Great guy to deal with, reasonable prices, quality parts.

 

[Chopperdriver]

Could it be wired incorrectly with the start wire going to the coil and the ballast wire. I think this will overheat the coil and cause problems.

I wouldn’t think so, I’ve driven it about 1,000 miles with no probelm and this just started.

 

[Chopperdriver]

+1 on the ECU.

A year ago or so I had very similar problems and tested all I could before buying new parts. Swapped in a Standard Motor LX-101 and all was good again. It's a pretty cheap and cheerful ECU, rockauto carries them

Part ordered, should be here tomorrow.

 

[Sixpactogo]

Part ordered, should be here tomorrow.

Did you check resistance on your ECU? I bet it is high.

 

[halifaxhops]

classic aftermarket or replaces xxxxxxx ecu issue. I will have my tester at Carlisle if needed.

 

[JimmyG]

I have had the exact same problem on a few vehicles when the coil gets a few years on it. Once hot,...quits. Cools for even a moment and away we go until it happens again. Replaced it, problem solved. Try it, you'll like it!

 

[FrankieD]

I think I’ll replace the whole electronic ignition package to start. Pretty cheap kit and would hopefully eliminate most of the things it could be. Forgot to mention the car is gorgeous

I would, had a similar issue on a 74 Imperial and that fixed the problem. Obviously electrical, whatever it is.

 

[Thomas]

I've also experienced this type of problem. A simple replacement of the Ballast resistor took care of the issue. When the resistor got hot the winding separated, once it cooled down a connection was made and it would start right up.
Don't over think the situation.

 

[tyke]

chck the fuel pump, mine use to get hot and shut down until it cooled off

 

[Chris N]

“Brutus”! A ‘70 300 went out for a Memorial Day cruise and he cut off after about 5 miles. Let him cool off and would run about a mile before cutting off again. Thought it was a bad coil, swapped it out but doing the same thing. Temp staying under 190, fuel pressure seems good (electric fuel pump) Hmmmmm… any ideas?

View attachment 536861

My 71 Fury did the same thing. It turned out my gas tank wasn't venting. The pressure built up and cut off the flow. I released the cap, heard the pressure come out and the car started. I had to do this every 20 miles on a long trip on a hot day.

 

[Chopperdriver]

+1 on the ECU.

A year ago or so I had very similar problems and tested all I could before buying new parts. Swapped in a Standard Motor LX-101 and all was good again. It's a pretty cheap and cheerful ECU, rockauto carries them