Car only run with key in start position .

[429bossman]

70 GTX 440-6 will try and start then will die when key is in run position after start .When engine cranks have power to the coil as soon as you stop cranking power loss.

 

[dadsbee]

Ballast resistor is toast... or the ignition switch or a wire from same. I'd start at the ballast. Jumper the two terminals temporarily and then try to start it...

 

[Nevada dan]

I would say ballast resistor

 

[429bossman]

Thank you were both right on . Problem solved .

 

[BobH]

Might want to buy two-carry a spare in the glovebox.

 

[joe smith]

Friend had a brand new early 70's cuda ( 340) that would do this intermittently.. It was on warranty and the dealer could not figure it out..
It was that new fangled POINTLESS ignition system and it was the spark box.( Not the correct term) The car acted up while he was at the dealer and they swapped it out with some different box's.... Some of the new ones they tried on his car were bad...

 

[F4R/T]

Ray @HALIFAXHOPS has some of those if you need good ones! Also throw a spare in the glove box.

 

[HALIFAXHOPS]

Thanks. I do have some all tested also. Prob have the proper number one also if it is a 100 point car.

 

[Should be playing golf]

Ballast resistor could be Ok but the connections could be loose or corroded.

 

[Moparmann]

Might want to buy two-carry a spare in the glovebox.

In 40+ years of driving Mopars, I've only had a ballast resistor go out ONE time, LOL!!

 

[440 PHIXX]

In 40+ years of driving Mopars, I've only had a ballast resistor go out ONE time, LOL!!

I’ve never lost one. And other than a Mark V that I had for 2 weeks before I wrapped it around a tree... and a’71 Caprice that threw the timing chain after a month... I’ve been driving rear drive Mopars since 1983.

 

[Ron H]

Encountered this problem on my ’63 while back. As posted, it is usually the ballast or ignition switch. Wasn’t so lucky as those checked fine. Come to find by some lengthy tracing it was the ignition wire at the BH, looked overheated after removing the harness. (Had new engine harness in.) Road vibration or closing the hood would droop the harness just slightly and it was stop time wherever I was. After some other ills with the old BH this finally prodded me to install a new one. Figured problem solved…nope same thing happened. This was the result of the prior bad connection creating heat that infiltrated the ignition connection in the harness. Removed that connector from the harness and refitted with a new connector that finally ended the problem.

 

[Archie Duiker]

Ballast resistor is toast... or the ignition switch or a wire from same. I'd start at the ballast. Jumper the two terminals temporarily and then try to start it...

I have changed the stock ignition on a couple of my Mopars to Pertronics 2, which uses full 12 volts at all times. Then I soldered a solid wire in the back of the resistor to keep it looking stock. Very reliable, and no more resistor failures.