Electrical Gremlins: Roadrunner Dying While Driving and Idling. Help!

[70runner]

If you don't find an electrical gremlin, assuming mechanical fuel pump, check the fuel pump rod for wear. Daughter's 69 Charger (recently rebuilt 440) behaved pretty much as you described in OP. Checked electrical, stock points, et al., everything seemed fine. Would startup and run for awhile. Checked fuel flow, seemed OK. On a hunch, removed fuel pump and checked rod. Obvious wear. There was a bad aftermarket batch of these, suspect engine rebuilder installed one. Replaced with NOS rod, has run perfect for a year since.

 

[Ron H]

Yeah, good idea to inspect electrical connections and grounds. One time I had ghost stalling but with key run-on, that more often has been due to a ballast or ignition switch. In my case it was a poor connection at the BH (ignition wire). It seemed tight, but on closer looking, seemed some duration with a poor contact caused overheating damaging the connector, guessed that engine or road vibration caused the loss of connection and stall out.

I keep an extra ECU and ballast in the trunk as a fast way to rule those out or spare parts if one of those is the culprit. On the subject, ensure the ECU is well-grounded.

 

[turbine68rt]

If you are running the Mopar electronic ignition or points a 1.5 ohm is used.

I'm using a 1.4 ohm coil and a 0.5 ohm resistor. Got it as close as possible to original specs with points.

 

[InViolet70]

Yeah, good idea to inspect electrical connections and grounds. One time I had ghost stalling but with key run-on, that more often has been due to a ballast or ignition switch. In my case it was a poor connection at the BH (ignition wire). It seemed tight, but on closer looking, seemed some duration with a poor contact caused overheating damaging the connector, guessed that engine or road vibration caused the loss of connection and stall out.

I keep an extra ECU and ballast in the trunk as a fast way to rule those out or spare parts if one of those is the culprit. On the subject, ensure the ECU is well-grounded.

ECU is grounded at 0.6 ohms, so all good here. What do you mean by BH ignition wire?

 

[BLK 68 R/T]

ECU is grounded at 0.6 ohms, so all good here. What do you mean by BH ignition wire?

Guessing BH=bulk head.

 

[WileE]

All of these electrical checks are fine... after you take 5 minutes to rule out the fuel delivery system.

 

[Geoff 2]

I see a hose going to the Vac Adv unit on the dist. The VA unit flexes the p/up wires during operation. Eventually the wires break, may make intermittent contact. So if the VA unit has done a lot of miles, it could be the culprit. Test with an ohmmeter while flexing the wires.

Look for loose, corroded connections. If ok, module, coil, bal res