1972 Dart Swinger won't start

"Let's start"

With ignition.

In a Mopar, for many years, you have TWO separate contacts in the ignition switch..........."IGN 1" and "IGN 2". IGN1 is hot ONLY in the "run" position, and feeds power up to the cluster/ gauges, etc, as well as out through the bulkhead to the ignition system (to the ballast resistor and through it to the coil), to the voltage regulator IGN terminal, the blue alternator field, electric choke if used, any smog devices such as idle solenoid

THAT IGN 1 IS NOT HOT during cranking................

So when starting the car USING THE KEY, the IGN2 comes into play. This is (many years) a brown wire comes off the IGN2 contact on the ign switch, out through the bulkhead connector, and ends at the coil side of the ballast resistor. THAT IS the ignition power for starting, and feeds a "good hot" voltage to the coil for starting

SO WHAT?

What else you need? You need tune up tools, timing light dwell, but you also need a MULTIMETER, a 12V test lamp, a few alligator "clip leads" and an inline spark tester.

"Rig" your spark tester to the coil high voltage tower to ground. "Rig" it so you can see it through the hood gap, and crank the engine USING THE KEY. You should get a nice hot spark at least 3/8" and more typically 1/2" long, a bright blue "snap." DO NOT USE the resistor coil wire for this test, use a SOLID core wire. If you "rig" your tester in "open air" you do not even need to use high voltage wire

NEXT

Hook your voltmeter to the coil+ Crank the engine using the key. You should have "same as battery," meaning whatever the battery reads during cranking. You need AT LEAST 10V 10.5 or higher is "better."

POINTS

Breaker points can be poorly adjusted, dirty, burned, greasy, and exhibit high resistance. They can be physically misaligned and make poor contact

CONDENSER The condenser MUST BE good. There are several things that can go wrong with them, the only "good" way is to try and buy good quality brand name ones (hard nowadays) and keep the old one if it was OK. Substitute one or more if you "think" one is bad

JUMPERING THE STARTER RELAY. Many people, including me, do this occasionally to crank the engine. Here's the situation you "set up" when you do this.........

With the key "in run" the coil is getting voltage through the ballast. With the engine stopped, the battery barely at 12V, and through the ballast, you might have 8V at the coil.

WHEN YOU jumper the relay to crank, that 8V goes DOWN, because now there is nothing to bypass it. You might only have 4-5V at the coil. DO NOT check spark when jumpering the relay it will give you skewed results