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Enrichment Overview

The stack of extra-fuel corrections layered on top of the base calculation, each solving a specific cold or transient problem.

What it is

The speed-density calculation gives the steady-state fuel for a warm engine. Real engines need more fuel in several specific situations, so Engone layers a modular enrichment stack on top. The layers, roughly in the order they apply over an engine's life from cold start:

  1. Cranking — extra fuel only while the starter turns.
  2. After-Start — a decaying boost for the first minute after it catches.
  3. Warmup — sustained extra fuel until coolant reaches operating temperature.
  4. Acceleration — a transient squirt when the throttle is opened quickly.

Alongside these, the Cold-Idle target raises idle RPM while cold.

Why it matters

Each layer exists for a real physical reason:

  • Wall-wetting — fuel condenses on cold intake walls instead of reaching the cylinder, so cold and transient conditions need a richer command to compensate.
  • Cold atomization — cold fuel vaporizes poorly, so more is needed for a combustible mixture.
  • Transients — when load changes suddenly, the steady-state math lags reality for a moment.

These corrections multiply or add onto base fuel; they don't replace it. When the engine is warm and steady, every enrichment layer has tapered to neutral and the base calculation stands alone.

How to tune it

Tune each layer on its own page, in the condition it targets — cranking while cranking, warmup while warming up. Treat them as independent: a too-rich cold start is a cranking/after-start issue, a too-rich warm idle is a base-table issue, not enrichment.

Rule of thumb

If the engine is rich only when cold or only during throttle stabs, look to enrichment. If it's rich everywhere, all the time, look to the VE and lambda tables.

In the game

The enrichment settings live on the Fuel page. Live readouts show each layer's current multiplier so you can see them taper as the engine warms and settles.