Engine only runs with the key in the "start" position

What is happening here is:

The "I" terminal on the solenoid is providing the coil with "full battery voltage" during cranking (as it is supposed to do). This feature sort of boosts the coil, while the starter is robbing the juice from the ignition system.

Your problem lies between the coil and the ignition switch.

Is this a recent engine swap?

Has it been fine for let's say the last six months?

Did this happen when the coil was replaced?

Explain the dash better, nothing works on it?

I can provide you pictures, wire diagrams, and will be willing to aid you all I can (I can usually make the hardest heads understand the Jeep basics on up complicated stuff! LOL!) if needed.

Do you have a test light or a voltmeter?

I fully understand your situation, I would be beyond bummed without driving either of mine.

The Medic

Test 1 (below)

Is your coil like this? (Is the coil hooked to original wiring?)

The Medic

The engine swap was done about three years ago.

About six weeks ago I decided to redo my dash (take out every gauge and put just oil pressure, temperature, volt in a new dash blank) and line the interior with a roll on bed liner.

Everything was fine before this.
the Jeep has not run for around seven weeks.

When wiring the light switch back up I went to start the jeep to make sure the battery is charged and I had no spark in my plugs, replaced the plugs and battery now It will start only when cranking.

The volt gauge is not wired in yet. The dash is sitting in the tub waiting to go on. My lights work.

I do have a test light and I can borrow a volt meter if I need it.

Thank you for the help!

So if I bought a coil for a 1978 351w would that be an issue with a resistor?

I think I bought one for the 351w, but yes the coil has the red wire, green wire and plug wire.

Do you have factory tilt steering?

Of course, you checked your fuses?

The Medic

Yes, factory tilt steering.

And I was under the assumption that fuses would have nothing to do with a starting issue. Uh oh, lol.

Coil part number-store it is from?

I will see if it has an internal resistor or not.

Is the coil hooked to original Jeep wiring?

The Medic

I am on the road right now. I will check that number in about one hour. It is from O’Reilly’s and yes I believe so duct tape on all the splices.

Sorry for the late answer. The coil is a Masterpro 2-5190.

Let's do some testing.

I made you a diagram. Took a little time, but I got it! Found the other on the net.

This a non tilt ignition switch. (Mine!)

The wires (colors and size) should be the same for a tilt ignition switch.

The Ignition switch is in a heck of a spot. The other side of the dash on top of the steering column. You will have to leave in installed to test it.

Mama's hand mirror and a good light will aid you.

Ground your test light, turn the key to "on", stick the test light's point into the plastic connector, next to where the wire enters it.

You should light up on all but the blue and (single) black wire.

This will verify that the switch is good.

The light blue wire is "S" "cranking"- works when the key is in the "start position"- you say that it works!

The black wire is brake failure- disregard it for now.

The big red wire is "battery" or the feed for the ignition switch. Hot all of the time.

Everything else will be "hot" when the key is in the "on position".

We are most interested in the "red and black" wires that enter the same slot. Right beside the blue wire ("S"). The red one of the two feeds the coil.

If all is good, we will be chasing wires on a wiring diagram.

Let's hear some news. Your Jeep cannot be down too long!

The Medic

Pictures did not come through the first time.

Thank you so much for the diagram, that helps a lot! I will conduct this test Monday.
I have two Jeeps and they are both down right now. :( The other one had the alternator bolt break off in the engine block hopefully fixing that one today.

I cry just a little bit (so nobody sees me) when one of mine is sick.

Waiting on some news!

The Medic

Forgot this - your coil looks correct.

The Medic

Key turned to “on” All light up but the blue (unless cranking) and the black.

Sorry for the late response, we have had the prison on lock-down this week so I am working longer hours than normal.

Is the next step seeing how many cranking volts I have at the coil?

Test the positive side of the coil voltage with the key on.

Test it again while cranking. ("I" should be generating a little more voltage)

The Medic

What setting should I have the voltmeter on?

The test light does not show any power on the positive side of the coil with the key to “on” but lights up when cranking.

Anything above (and close to) 12 Volts DC. Many meters have 20 Volts DC as the selection above 12 volts.

Volts while cranking means the "I" terminal is working on the solenoid. This is good!

We seem to not have voltage originating from the "Key/ Ignition switch.

Check your fuses/ follow the wire from the positive side of the coil towards the firewall, look for breaks or shorts.

How am I doing as the teacher?

Keep me posted.

The Medic

Thank you so much for the help! I will conduct this test tomorrow after work. And look for any breaks. I will send pictures too.

Pretty sure I found out what the issue is!
The red/white stripe wire coming from the ignition switch splices not even five inches from the ignition switch. I had cut the wire on that splice, that goes through the firewall and into the electronic control module. So that is where my break is. Going to wire it up tomorrow and see if it fires up.

How are things going?

The Medic

It fires up and runs great! Taking them to Telluride, CO next week. Thank you very much for all the help. How do I give donations?

Wonderful!

Never did send us a picture of your rig.

Many times it is obvious little stuff that messes you up. When I get in binds like that I will go through the motions, this does this, makes this do this, etc., and follow along with the flow of things with my finger.

Keep us in mind for the future, if you need me, request CJ MEDEVAC!

Happy Jeepin'!

I messaged the boss on the donation procedure, he will probably show up here soon.

The Medic