Smoke limiter tuning: balance air mass and injection quantity

A smoke limiter map caps permitted injection quantity against the available air mass. Depending on the ECU family, its axes may use air mass per stroke, engine speed, lambda or a derived air-to-fuel relationship.

Increasing IQ alone does not create clean power. Driver Wish, torque limiters, Torque-to-IQ, boost control and the smoke limiter must form a plausible torque chain. A stock limiter can restrict the requested quantity, while indiscriminate increases can cause smoke, excessive exhaust temperature and unnecessary thermal load.

Start by checking axes, units and scaling. Then compare air mass, boost, target lambda and actual injection quantity across the relevant speed and load range. Apply changes progressively and validate them with logs, exhaust temperature and the engine’s real mechanical condition.