1968 Cj5 No Spark

Trying to get my Jeep running, and I have no spark. Any ideas?

I have replaced the spark plugs and wires.

Maybe ignition Coil?

 

Start at the beginning. One step at a time.

Was it running previously? If so what has changed? Are all the ignition wires secure and in place, especially between the coil and distributor cap?

Open your FSM and use it to make sure the points are clean and set correctly. Distributor rotor and cap clean and dry, inside and out? Is the rotor in place?

With the key on, does the coil HT output wire make a strong hot spark when set 1/4" from a ground when cranking? (Or when the points are opened and closed manually?)

Is there voltage to the coil? It should ground out from there to the coil, but act intermittently as the points are opened and closed or while cranking. (Which causes the coil to spark.)

Do you have voltage to the distributor and points, which then ground the coil as they operate?

If there is no voltage to coil or distributor, go back to the ignition switch and verify it sends voltage to then ignition circuit when it is "on." How about when on "crank?"

 

I just saw you also have a post for "no crank."

Your Honor, the witness is withholding evidence!!!

Since you report working on the ignition switch, go back and check your wiring.

One test can be to run a hot wire to the ignition coil input, then see if you get spark at the plugs

 

I’ve never had it running. It didn’t even crank over when I bought it

 

Okay.

The only logical way to do diagnosis is from "known good" basics. It could be as simple as corroded points, but guessing will just lead you in circles.

So first use the FSM to do a careful tune-up to specifications - especially the points and static timing. (Or possibly it has electronic ignition, in which case... call an exorcist. )


There are only a limited number of possibilities, if you eliminate them one at a time sequentially.

 

Does it crank?
If so, then with the key on and the points off a lobe and propped open ( you can use a piece of paper or the like):
Remove the pigtail at the - coil post and check for power at the coil (+)
If no power then you have an issue between the ignition and the coil
If so:
Check for power at the - post. If not bad coil.
If so:
Reinstall the pigtail and check for power at the points. If no power, you have a bad/grounded pigtail/point set.
If so:
Remove the paper and open and close the points with your finger. You should get a spark from the coil.
If not:
Then your point gap is too wide or you have corrosion on the points face. Dress, regap, and try again.

 

I just had a similar issue with mine, Crank no spark.
. Validated 12 volts at the coil with key in run and while cranking
. Validated the points were opening and closing
. Validated 12 volts at the points. Oh wait, the points were closed, so should not have had 12 volts there.
. Clean the points and now have spark and the engine fire up. Yeah!

 

got it running! thanks guys!

 

On an old vehicle the vast majority of the time no fire is caused by points, condenser or the ballast dropping current too low.

 

So.... what did the trick???

 

X2. Feedback is always helpful for us to add info to our internal knowledge banks.

 

............. Come on bro can't leave the boys hangin, well at least not us boys your boys you can do with what you please....