What it's for
Cranking Ignition Angle sets the spark advance used whenever engine speed is under the Max Cranking RPM value. Once RPM climbs past that point, the ECU hands over to the normal base ignition table. It's enabled by default and supports up to 3D mapping, so you can, for example, vary cranking timing with coolant temperature for easier cold and hot starts.
Cranking speed is slow and uneven, so the engine can't tolerate much advance. Too much and the spark fires early against a slowly rising piston, which loads the starter and can kick back. Too little and the engine is slow to catch.
What to check
- Confirm base timing with a timing light first, or the cranking value won't mean what you think.
- Make sure
Max Cranking RPMsits above your real cranking speed but below idle. - Log a few cold and hot starts and adjust in small steps.
Need this diagram? Ask us and we'll send it over with advice for your build. See also ignition tuning.
