Zakszi drag-street 3.5 turbo E30
This car inherited internals from TurboĆ's old BMW 745i E30 turbo setup, and has totally custom bodywork -made by the owner.
We had interesting issues with ignition.
Originally (in former chassis) the engine and VEMS was working fine when removed. In this chassis it had spark problems from the beginning.
We exchanged many coils, cables, distributors and plugs (and set minimum gaps). Sometimes it was better, sometimes not.
Finally ended up with the solution: Ignition output (IGBT?) is instable. Sometimes is sparks, sometimes missing and sometimes can't switch power.
Interestingly, switching a 3W bulb ON/OFF with MDH commands was always fine, moreover primary coil of ignition has been examined with a scope, and switching was always on time, still it couldn't give spark every time (can't handle power?)
Change to another IGN output solved this strange problem.