No power to distributor plug

[73dds]

So I just put a fresh motor in my 73 Dodge Dart Swinger. I went to crank it over and no spark. I have fuel and air but no spark. There’s power at the coil, power coming from the coil wire, but nothing at the distributor. I checked for power at the plug for the distributor with the key on and nothing. Help would be very much appreciated. I’m 18 and building this car on my own budget and need it done before prom haha

 

[lilfontleroy]

first thing you should verify is TDC @ #1 and orientation of the rotor, if it's 180 degrees off you'll get nothing
you got the coil leads (pos & neg) the right way around?

 

[73dds]

first thing you should verify is TDC @ #1 and orientation of the rotor, if it's 180 degrees off you'll get nothing
you got the coil leads (pos & neg) the right way around?

I know for sure the coil is wired correctly and when I put the distributor in the timing mark on the harmonic balancer was at 0 and the rotor was facing plug #1

 

[TrailBeast]

I know for sure the coil is wired correctly and when I put the distributor in the timing mark on the harmonic balancer was at 0 and the rotor was facing plug #1

You won't see power at the distributor plug unless the distributor is turning, and then only about 1 volt AC between the two contacts on the end of the wire.
BUT, with the key in the run position you should be able to touch the bare bullet on the harness side of the distributor plug to ground and get one spark each time you touch.

This assumes you are using the OE ignition module and ballast resistor.
Module MUST be well grounded.
Gap for the magnetic pickup in the distributor should be about .008 and set with a non magnetic feeler gauge. (I have done tons of them with a standard feeler gauge and never had a problem)

Your wiring should look like this, and note the notes at the bottom.

 

[67Dart273]

I know for sure the coil is wired correctly and when I put the distributor in the timing mark on the harmonic balancer was at 0 and the rotor was facing plug #1

This actually has nothing to do with your stated problem but also does not confirm timing is not 180 off. You must be sure no1 is on the COMPRESSION stroke. There are only two ways (handily) to do this

One is to remove no1 plug, crank the engine with your finger in the hole, and stop when compression blows your finger out. Now bump/ wrench the engine a little and look for the marks 'coming up.'

second way is if you have either valve cover offf. Bring the marks to TDC and look at no1 and no6 valves. Whichever pair is closed, is the cylinder on compression....ready to fire

Some things about ignition;

 

[67Dart273]

Here's a post I made about the simplest way I know to get across testing the ECU/ ignition parts

74 duster electrical problems


You need a coil, the ECU and the distributor

Lay it out on the bench. Follow the diagram. Find the two distributor pickup terminals on the ECU. Hook them to the distributor

Hook the ECU case to battery NEG

Coil does NOT need grounded

Distributor does NOT need grounded.

Hook coil + to the power lead terminal on the ECU. Get a clip lead hooked there and let dangle. This is your battery "hot" when you are ready

Hook something from coil "case" to a probe for testing spark.

Hook up your power clip lead. Twist the distributor shaft while holding the test probe near the coil tower. The thing should make sparks

If not, unhook distributor. Take first one, then the other pickup clip leads, and "tap tap" ground them at the battery connection. Coil should make 1 spark each time you do so.

If not, try another coil. If that does not fix it replace the ECU

IF you hook it all up and it WORKS, then there is something AFU in the car harness. SUSPECT a bad ECU connector OR a bad DISTRIBUTOR connector
=============================================
This is all you need to test the basics of the ignition. You can easily test the ballast separate. A battery, the ECU, distributor and a coil, and of course some test leads

Below, the basic diagram for a 4 pin ECU

Below, the wire for testing spark. I use my 12V test light. No, LOL the spark won't blow up the bulb

Below, the ground connection. ALL you need is one wire from batt NEG to the ECU case

Below, the two distributor connections. In the car these are polarity sensitive, but for testing does not matter

Below, the coil NEG connection

Below, battery PLUS connection, one wire to this terminal of ECU and jumpered over to + side of coil

Below, all hooked up and ready to test (except for battery ground). Should produce sparks at least 3/8" and typically 1/2" long

Below, distributor "one wire" test. I have removed the other distributor wire for simplicity. Take the bare connector end or this clip lead (the yellow) and with everything hooked up, ground it repeatedly. Each grounding should result in a spark (In this photo you need to hook up the ECU ground wire, I left it off for the photo)

 

[67Dart273]

Turn key to run. measure coil pos and neg voltages. Coil pos should be somewhere 6--10V. Coil neg should be below 2V

Leave key in run, 'rig' a test gap at coil tower. Take the engine bay harness end of the distributor connector. 'Tap" the bare end of the connector to ground, a "snap" single spark should happen each time

Examine the cap/ rotor for carbon, damage, water, dirt, etc. Examine rotor for "punch through" to the shaft

Check spark with a SOLID core wire and a test gap

Examine reluctor/ pickup for rust, debri, strike damage, and wiggle test shaft for excessive play. Check the reluctor / pickup gap with a brass feeler gauge. .008" that is inches not metric

ECU MUST be grounded. Remove voltage regulator and ECU, clean around mounting holes on firewall and on ECU/ VR and remount using star lock washers.