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Old 11-25-2020, 03:24 PM   #1
leecatd8209
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Join Date: Jul 2015
Location: South Texas
Default EZK Failure with wasted spark conversion

1990 240 DL NA B230/M47. Stage 0, no other issues.

I did a wasted spark install with the Buchka board using a Miata J702T ignitor and the Bosch 2x2 coil. The car runs great with the conversion in place, but twice now, the EZKs have failed out of nowhere. Both times I got a "this isn't running quite right" vibe just before the failure. It seems to run fine indefinitely when I go back to the stock ignition setup.

I'm using the stock Miata harness pigtail for the ignitor, and a Land Rover pig tail for the coil, and the wiring is sound, the solders for the Buchka board installation are fine, and the board works when I transfer it to a new EZK.

I've asked around about this issue a little in my "build" thread, but haven't really gotten anything solid, and I don't want to keep burning up these boxes. So far the only plausible explanation I've received is to make sure the ignitor box is mounted in such a way that it's physically grounded. I have it mounted on a chunk of aluminum as a heatsink, but the assembly is just floating in space.

Any ideas, or other places to look for causes of EZK failure? Any methods for bench testing these to determine the failure point? I'm not seeing anything obviously burned, melted, blown out, or otherwise bad on the Buchka board, or the EZK and daughterboard.
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