73 Plymouth Duster 6 - no spark


Car Talk Buds, I have a Duster 225 slant six with pointless ignition and there’s no spark. I’ve only been starting it every few months and last time it fired right up. Do I need to remove the distributor and clean the pick-up coil? Do the modules ever go bad? How about the coil? Just a little Ignition Systems 101. Thanks in advance.


Check that the rotor is turning when you engage the starter. Years ago, I had a no-start situation with one of these engines that turned out to be a stripped distributor drive gear. Only by observing the rotor did we figure out what the problem was.


Also, check that you can’t turn the rotor by hand. Sometimes, the rotor will “hog” out. Check the button in the center of the distributor cap. Push it in against the little spring’s tension. If it doesn’t spring right back, replace the cap.


Ah the old Chrysler Electronic Ignition system. I would check the ballist Resistor mounted on the firewall. 99 times out of 100, on a non starting Chrysler, that was the culprit. Always buy two and throw one in the glove box.


One other thing to look at is the ballast resistor high on the firewall. These are notorious for failing. There are actually two wire elements in it. One heavy resistance wire for the B+ for the coil and a lighter resistance wire for the ignitor box. The ballast is located where moisture can get to it so it often fails after a car wash or similar.


Having owned this exact make and model, I have to agree. Check the ballast resistor. It was a common failure. Easy to test also. Just jumper the resistor and if the car starts, replace it. Don’t put in a permanent jumper, the coil will burn out if you don’t have that resistor in series. It’s OK for a short test, but not for long term.


Also check the connector plug to the solid state ignition module, this is either a 4 or 5 pin unit and the wire connections to the connectors go bad due to vibration. Run a continuity check between each wire, they run from the ballast resister and the voltage regulator.

Alternatively you could wiggle the wires around, if the car starts wiggle the wires around a little more to see if it cuts again.

If this proves to be the problem then you can put a jumper wire in place until you can track down a new plug and wires ~ they aren’t that easy to come by.

Other contenders are the impulse sender, this is a complete assembly screwed to the dizzy baseplate, and of course the ignition module itself.

But do check the ballast resister mentioned by other posters.


That’s the solution . . . cheap and easy too! They fail every so often and like Alfa said . . . buy two, keep one in the glove box. Rocketman


I can’t agree more about the ballist resistor…I use to keep a extra one in the glove compartment. I think I replaced that thing 3 times for the 2 years I owned my 77 Aspen. Mine was located on the firewall. That slant-6 engine was GREAT though.


Thanks for everybody’s response! I cleaned the connections for the ballast resistor and the ignition module plug and it fired up like a charm! A cheap fix. You guys are great.


And, thank you for coming back to let us all know what worked. Even when we get it wrong it’s nice to hear what the problem turned out to be.


And, thank you for coming back to let us all know what worked. Even when we get it wrong it’s nice to hear what the problem turned out to be.

I love playing Stump the Chumps…