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The car in question is a 1971 240z with a 280z engine and 280zx distributor.

I'm currently having some issues getting spark from my 6A MSD. At one point, the car did run fine with this exact setup and wiring shown in the attachment to this post (and here: https://www.classiczcars.com/uploads/monthly_2016_10/1918msd_zx_240z_1r2.jpg.9235e4af03e7d71e6584ff639ad81311.jpg) . However, the car currently isn't starting with this configuration. I was having some stuttering issues in the past, and the last two times I took the car out, it died and had to get towed home.

The car seems to run fine if I bypass MSD entirely and wire the ignition module and tach directly to the coil. With the MSD, I do not get spark from the coil. I have a brand new cap, rotor, ignition module, and wires installed.
Here's where I am currently at with my troubleshooting:
  • I am able to get spark from the coil wire when doing the green/purple and white wire test indicated in the MSD manual (see below). I think this suggests that the MSD is wired correctly and is capable of firing.
  • New MSD. Did not work. I replaced with a 6AL and did not get a flashing LED when cranking. So, it doesn't look like the MSD is picking up any signal from the ignition module. This also came with a new wiring harness, so I'm thinking all the wiring should be good.
  • Replaced ignition module. Didn't seem to help.
  • Bypassing the MSD. Car starts and runs just fine.
  • Bypassing the tach adapter. Still no spark.
  • Directly wiring the B/W wire from MSD to the battery to eliminate the possibility of the ignition switch causing any issues. No spark. Its also worth noting that I have confirmed that, when the MSD is wired as shown in the diagram (ie not directly wired to the battery as previously mentioned), this connection sees 12V when switched on and around 9.6v - 9.8v when cranking.
Running out of ideas here, so I'm hoping someone here can help me out!

MSD Manual test procedure: https://www.jegs.com/InstallationInstructions/100/121/121-6425.pdf


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