Without an accurate trigger system to ensure your ECU knows your exact engine speed and position at all times, things can only end in disaster.
This is because without this accurate information all of your fuel quantities and ignition timings will occur at the wrong time potentially, very likely causing catastrophic engine failure.
While on a stock engine you’re unlikely to ever have triggering issues, once you start modifying things it can become an issue, particularly with increased harmonics. Some engines like Nissans RB series are more susceptible to this issue than others, but there is a solution as Andre explains which involves switching from an optical trigger to a crank trigger system.
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