Outputs¶
What the ECU actively drives and manages — plus the dyno tool you use to measure the results.
What the ECU controls¶
Beyond metering fuel and timing spark, the ECU runs several control loops that manage how the engine behaves at the edges of operation:
- Idle Control — holds a steady idle by trimming the throttle blade, with a dashpot and anti-stall.
- Cold Idle — raises the idle target while the engine is cold.
- Decel Fuel Cut (DFCO) — cuts fuel entirely on a closed throttle at speed, for economy and engine braking.
- Rev Limiter — cuts combustion at the RPM you set.
- Exhaust Pops & Afterfire — the burbles and bangs that unburnt fuel makes in the exhaust.
And the measurement tool:
- Dyno — loads the engine and measures power and torque.
Why it matters¶
These systems are what make the engine drivable rather than just runnable. They handle the transitions — coming off throttle, idling cold, hitting the limiter — that a bare fuel-and-spark calculation doesn't cover. The dyno is how you turn tuning changes into measured numbers.