Let's get terms straight:
CRANK: Means the starter operates, either with key or "jumping" the rely, engine rotates
TURNS OVER: Same thing as above
FIRES: Tries to start, coughs bangs, shoots flame, or tries to run
FIRES AND RUNS: Obvious, starts and runs, and can be specified, IE "runs for a few seconds" etc
RUNS: Same as above
IF IT WILL NOT crank with the key, this is a 74, and has (had) the hated seat belt interlock. This is a reset button on a rectangular "looks like a horn relay" on the driver side fender apron. Find the two yellowish wires and splice them permanently together at the reset device connector
So does it crank with the key?
CHECK SPARK: In these situations, check spark right OUT of the coil and do NOT use the coil wire. "Rig" a test gap, either build or buy one, or use a spark plug, and "rig" with wire core wire, even if low voltage wire---you can "hang" it out in the air away from other parts. Look through the hood gap, twist the key, see if you get nice blue, snappy hot spark
If not......
You need a mulitmeter, test lamp, a couple of alligator jumper wires "in general". If you do NOT have a factory shop manual GET one
You can download the 73 manual from MyMopar for free BUT DO NOT USE the wiring diagrams in that manual, as the 73 and 74 are DIFFERENT.
I created a downloadable wiring manual but IT MAY be flawed, let me know, go here:
Free service manuals
Go to post 64, click the black icon and "save as."
CHECKS YOU CAN MAKE
Turn key to "run." Check coil + voltage to ground, It should be LESS than battery, perhaps 6-8 or maybe 10V and not much higher. Coil NEG should read LOW perhaps 1-2 V and no higher
Rig your test gap. Separate the distributor pickup connector, and take the engine bay end of the connector. Tap the BARE end of the connector terminal to a ground. You should get one blue hot "snap" spark each time you do so
Remove cap, rotor, inspect for carbon tracking, damage, moisture, rotor "punch through"
Inspect reluctor / pickup for damage, rust, debri, wobble, loose / sloppy shaft bearings.
Hook your meter to the distr. connector and crank engine. With meter on low AC (that's right AC) volts the dist. should generate about 1 volt AC
Ignition box MUST be grounded. Pull connectors loose, inspect for corrosion. "work" in/ out feel for tightness, and this will "scrub" the terminals clean
