FOME-Tech
Cyl 1 tdc detection by crank decelleration
If we are looking at the speed of the crank for each piston then we should be able to recognise the slow down of cylinder 1 when it's on its compression stroke. With that we should be able to sync up which 360 rotation is the correct phase when using sequential without a cam sensor.
I brought this up in the discord a bit ago- can phase detection also be implemented without a cam sensor by also using "Enable faster engine spin-up" in the Cranking settings by watching acceleration when ignition happens on a phase guess?
If we are looking at the speed of the crank for each piston then we should be able to recognise the slow down of cylinder 1 when it's on its compression stroke.
how do you tell the difference between 1 and the cyl 360 degrees out?
A solid point, I picked up on it because there are some 3 cylinders and V twins doing it. As you note there are no cylinders 360 out on those...
David may have an idea here, if someone is willing to live with a longer cranking time then a guess with sequential ignition and a wait time of x revolutions to see if the engine starts would work at the risk of flooding cylinders.
Or as a probably non-viable idea but food for thought, wasted spark ignition but only firing half the injectors, so if the engine starts and the ecu detects crank acceleration it could only be from a cylinder receiving fuel and thus could only be one possible cylinder. Obvious downside is half the chance of the engine actually starting.