My 71 Buick gs 350 was running great til last week. I’m not getting spark. It has a pretty much brand new msd box and coil and I just replaced the coil wire and that didn’t fix it either. Replaced the spark plugs yesterday as well. What else could be causing this?
If it were mine, I'd jump the MSD directly to the battery positive and negative to bypass any ground/power issues. Depending on what you are using besides the MSD, you can bypass the MSD and run on your points/breakerless system without it to isolate the issue.
If have a 6A/6AL box and you want to trouble shoot it, here is a pretty good video. This is also in the instructions that come with the boxes, too. Trouble shooting starts at about 4:50... https://www.holley.com/blog/post/how_to_troubleshoot_an_msd_6a_6al_ignition_control/
Make sure the rotor is turning in the distributer. It's possible the roll pin that holds the gear at the base of the rotors shaft has sheared and that's the whole problem.
Are you are still running the stock points Dizzy ? Then many times I have seen the insulation dry rot off the points wire that runs under the breaker plate and then of course the wire shorts out fully or intermittently with the result of no spark. when I am tuning a car that still has a GM points type Dizzy the very first thing I do is replace this wire even if what I can see of it that’s not under the breaker plate looks fine! remember that wire in your Dizzy is 47 years old now.
I figured it out. The plug that’s plugs in from the distributor to the msd box wasn’t connected all the way due to the prongs inside being pushed not allowing enough connection. Thanks for the responses everyone!
