Corrigez les problèmes de démarrage à chaud causés par des erreurs de calibration ECU. Résout le démarrage prolongé sur moteur chaud.
The Hot Start Fix is an ECU calibration service that resolves extended cranking and difficult starting when the engine is warm or at operating temperature. This is a well-known issue on certain engine platforms where the factory ECU calibration does not adequately compensate for the different fuel vaporization characteristics and air density conditions present in a hot engine. The result is an engine that starts instantly when cold but cranks for several seconds — or requires multiple attempts — when restarted after a short stop.
This is not a mechanical fault. It is a calibration issue in the ECU software, and it can be resolved with a targeted adjustment to the hot-start fueling and cranking parameters.
When an engine is shut off at operating temperature, heat soak causes fuel in the injectors and fuel rail to vaporize. On direct injection engines, high fuel rail pressure can also drop during the soak period. When the driver attempts to restart the engine, the ECU applies its standard cranking fuel map — which may not deliver enough fuel, or may deliver fuel at the wrong timing, to account for the vaporized fuel and reduced rail pressure conditions.
On some platforms, the issue is compounded by inadequate cranking speed targets, insufficient priming pulse duration, or incorrect fuel pressure compensation during hot restart. The factory calibration may work acceptably in mild climates but fail in hot weather or after the engine has been run hard and heat-soaked thoroughly.
Our engineers modify the ECU calibration to improve hot-start behavior through several targeted adjustments. The cranking fuel enrichment maps are recalibrated to deliver the correct fuel quantity for hot-engine conditions. Fuel rail pressure targets during cranking may be increased to ensure adequate atomization. Cranking speed and duration parameters are optimized to ensure the engine fires reliably on the first or second revolution.
On platforms with variable valve timing, the cam phasing during cranking may also be adjusted to improve cylinder filling at hot-start conditions. The specific adjustments depend on the engine platform and the root cause of the hot-start issue on that particular ECU calibration.
Hot start issues are most commonly reported on certain BMW (N20, N55, B48, B58), VAG (EA888, EA211), and PSA (EP6, THP) platforms, though the problem can occur on any engine where the factory calibration has insufficient hot-start compensation. Both petrol and diesel engines can be affected, though the issue is more prevalent on direct injection petrol engines due to their sensitivity to fuel vaporization conditions.
Send us your original ECU file and describe the hot-start symptoms you are experiencing. We will analyze the cranking calibration and apply the appropriate corrections for your platform. Files are typically delivered within 30–60 minutes, with checksum correction included.
Dans la plupart des cas, non. Le démarrage prolongé à chaud est généralement causé par un défaut de calibration du logiciel ECU d'usine. Les composants mécaniques fonctionnent typiquement correctement.
Les problèmes de démarrage à chaud sont fréquemment signalés sur les BMW N20, N55, B48 et B58, les plateformes VAG EA888 et EA211, et les moteurs PSA EP6/THP. Le problème peut cependant survenir sur toute plateforme.
Oui. La correction de démarrage à chaud peut être appliquée avec un remap Stage 1 ou autre. Si vous commandez les deux services, prévenez-nous et nous appliquerons les deux modifications au même fichier.
Si le moteur démarre instantanément à froid mais tourne 3–5 secondes ou plus à chaud, et qu'il n'y a pas de codes défaut liés à la pression de carburant, au démarreur ou au capteur vilebrequin — le problème est très probablement lié à la calibration.
Les fichiers de correction de démarrage à chaud sont généralement livrés en 30–60 minutes pendant les heures ouvrables.