Hi Moparts...
I have a 67 Barracuda that I am trying to bring back from the dead. My current issue, among many, is I have to spark at the plug. It has an MSD ignition setup, juice getting to and leaving the coil, juice at coil wire into the distributor, but nothing making it to the plugs. Do I have a dead distributor? Its a 318 car, and I only have BB distributors I could swap in. The cap looks fine, everything under the cap "looks" okay. What should I be checking? After going through everything, motor turns over freely, and I think it will run, but without fire to the hole, nothing is going to happen....Let me know what you think. Thanks!
Dave in Colorado

If it"snaps", good going into distrib, then the distrib is working and may be the rotor burned through, causing spark from coil to ground to distrib shaft.

So, I have the same ignition set up in my SuperBee, so I did some comparison. In the Bee, using a basic test light, if the key is in the "run" position, not cranking the engine, there is no juice. Once the ignition is engaged to turn over the motor, I get the "snap" you are talking about. In the Barracuda, its a different story. There is no "snap", just a constant light, constant power. What does this mean? The Bee runs great, so I guess thats what I need to emulate, but they seem wired the same. The only difference I see is that the Bee has a standard OEM style coil, while the Barracuda has the MSD version.....seems to me something has to be wired wrong. Maybe I scrap the MSD setup and go back to OEM..?

Call MSD & have them tell you how to ohm/check the dist

Check the magnetic pick up in your current distributor with a decent Volt Ohm Meter and then check your BB ones also, it should read between 300 to 500 Ohms on between the two wires going into the distributor pick up is what I'm remembering now.
A quicker easier way may be to take one of your BB distributors and hook it up to your distributor wiring going to the MSD box and spin it by hand with the coil wire removed from the distributor cap so it can jump to ground and see if it will fire the box and coil
If so it is the 318 distributor, if not then it is the box or coil

^^^ Cab is dead on correct (& you'll know right off the bat if it is the dist) then you can go from there to see about getting it fixed/corrected.

OHM meter is reading zero. I started looking through my wiring and its spaghetti and I see lots of spots where it could fail. I am going to install a fresh wiring harness and start over. Robert...I read another post and you do not seem like a fan of the MSD products. Lets say for the sake of arguement that I pull the whole system out and put in something else. What would you recommend? Its a little 318 Barracuda, I am building it as a daily driver quality restoration, nothing crazy. The MSD thats in it has the knob for the variable timing adjustment, so I am not sure what they did with it in its previous life, but I am good with starting fresh. I got the car pretty cheap, for a 4speed fastback, so I have an open budget. My biggest concern with these old mopars is faulty wiring...I have had harnesses melt on me on my way to work, so starting with all new is on my list. Should I try and salvage the MSD unit, or toss it and go with something else?
Dave

SO let me retract part of that last post...I checked it again with an actual working mulitimeter, and its showing around 480 OHMS....I am going to acquire a small block distributor and swap them out and see what happens...maybe in a couple days.

My 72 fury will not start sometimes, no spark to the plugs. All I do is wipe off the top of rotor and it fires right up. Can see just a little gunk on top of rotor if I look at it close. Drove around all day saturday running great, but after stopping by friends house wouldn't start, so pop the cap wiped the top of rotor and started right up. I have tried different caps and rotors

If the magnetic pick up showed 480 ohms it is working, try removing it and hook it back up and spin it, the distributor, clock wise to see if it will fire the coil through MSD box or not
There is another test that I'm not remembering the exact procedure that will test the MSD box by grounding one of the wires, maybe it is the white point wire Contact MSD for the proper way to test your box

Dave actually I was being a bit facetious as I have nothing against MSD & I will stop doing that cuz it gave (you) the wrong impression (& it was my first time!). I do have one of those adjustable timing knobs (not hooked up yet) but I really want to try it. I would suggest pulling the yellow wire off of the starter relay to disable the starter & with the key "on" & a helper holding the key to "crank" you with your meter see if everything that should be fed (in both positions) is being fed & if OK there then confirm the MSD/coil etc (everything related) is correctly wired & if good then we'll continue on & find out which DEVICE is faulty then we will be in a better (informed) position to decide what to do next.

I found a troubleshooting guide online for the MSD units. I followed their testing notes, and have determined the box is functioning properly. Doing what they said, I got arc out of the coil wire....jumping to a ground point, and to my ungloved hand! That will wake you up in a hurry. Looks like its the distributor... Thanks for the testing tips...I learned a thing or two....
Dave

How wide is the air gap between the trigger wheel and your Mopar magnetic pickup?
It needs to be .010 or less on all eight points on the trigger wheel, make sure and use a brass feeler gauge to measure with, not a steel one

i was thinking about this "particular" test, but i believe you have already "discovered" it.

This sound exactly like my problem, try cleaning rotor and cap.