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360 degrees out of timing

Practical Dyno Tuning

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Currently going through the practical tuning modules and made me think (could be missing a simple point however), how does the ecu know if the timing is 360 degrees out or not?

So my car (Clio 182) doesn’t have additional timing sensors on the cams just the single crank sensor. Can’t work out how the ecu will know each time it starts. Must be a way, just not sure how it works it out.

Can anyone enlighten me?

It could be running wasted spark, where it fire two cylinders at a time, one is in compression, and one is in exhaust, and the spark is "wasted". Or it could be running sequential injection, and using a single cylinder manifold pressure sensor to learn when it's on the intake stroke (some single cylinder and V-twin bike engines use this technique).

Hi David,

Thanks for replying.

Yes is does use wasted spark. So that sorts the ignition out but surely it doesn’t fire both injectors too?

It will do, it's not uncommon, with each firing being half the required total.

Perfect. Thank you.