Strange electrical starting problem 71 440 Dodge

[mbc0724]

Car is a 1971 stock 440 with Chrysler electronic ignition and Edelbrock carb installed many years ago. Has been running and starting fine for years, until a few days ago. Starts up perfectly, can drive it around no issues. But after only 10-15 minutes if you turn it off, it will not restart. Instead, it will crank and crank and crank as if there is no spark--fuel is present--but no ignition or spark.

Then, your return in a couple of hours and it starts right up perfectly again, and drives fine, but after 2-3 off and on tests, it won't start again. It just cranks and cranks; no battery or starter issue. I'm afraid to take it anywhere. It's no issue getting there--but good luck coming home.

Any ideas re the cause of this problem?

Thanks!

 

[OMTWF-72SE]

I had a coil cause an issue like this. Didn't take it long to get enough heat from running to fail. Easy to check with a multimeter. Check primary (2ohms or less) and secondary (20k or so) when cold. Then when it stops working check again. Should be same, but will be an open if bad.

 

[ckessel]

Try this from Greg. Time for some trouble shooting.

Are you ready for a real weird one? Random NO spark from a MP electronic ignition system despite numerous parts swapped around...

 

[BeepBeepRR]

Inspect the coil make sure its not cracked or leaking. Easy check to do.

 

[Geoff 2]

Could be a few things, most likely coil or ECU. Unfortunately, problems like this arte fixed by substitution....

 

[Don Frelier]

Here's a suggestion to help determine if it's a bulkhead connection problem. (which it could be)
Start and drive it the 10-15 minutes but bring it back home.
Wait a bit.
If its an automatic then with the car in park put the key in run position.
Open the hood and jump the starter relay battery post to yellow.
If it starts then you likely have a problem at the bulkhead with the start wire to the ignition circuit.

Another possibility not mentioned is the pickup coil in the distributor. It will get hot after you shut off the engine.

 

[mbc0724]

I had a coil cause an issue like this. Didn't take it long to get enough heat from running to fail. Easy to check with a multimeter. Check primary (2ohms or less) and secondary (20k or so) when cold. Then when it stops working check again. Should be same, but will be an open if bad.

Good idea. I have a new coil sitting on my bench and will try tomorrow. Will let you know.

 

[mbc0724]

Try this from Greg. Time for some trouble shooting.

Are you ready for a real weird one? Random NO spark from a MP electronic ignition system despite numerous parts swapped around...

Thanks for the link