When your 2021 Kia Sorento fires up but immediately shuts off, and this pattern repeats with each start attempt, the engine is receiving enough fuel for initial combustion but can't sustain operation. This cyclic behavior reveals specific system failures.
Immobilizer Intervention
Kia's immobilizer system can allow brief engine running before cutting fuel if it detects an authorization problem. If the security light behaves unusually during these start-stall cycles, the immobilizer may be intermittently losing key verification and cutting fuel injection.
Fuel Pump Failure Pattern
A failing fuel pump may build enough pressure for initial starting but fail to maintain pressure once the engine runs. The engine fires, runs briefly on residual rail pressure, then stalls when pressure drops. Listen for the fuel pump prime sound when turning the key to ON - absence of prime suggests pump issues.
Idle Air Control Problems
The electronic throttle body controls idle airflow precisely. If it fails to maintain the correct position for idle, the engine may fire on starting enrichment but stall immediately when transitioning to normal idle. This is more common after battery disconnection when throttle position needs relearning.
Mass Airflow Sensor Failures
A contaminated or failing MAF sensor may provide acceptable signals during cranking but incorrect readings at idle. The PCM calculates fuel based on MAF readings - incorrect airflow data creates an air-fuel mixture that can't sustain combustion.
Crankshaft Position Sensor Intermittent
An intermittently failing crank sensor can allow starting but then drop signal, causing the PCM to shut off fuel injection. The engine fires on the initial signal but stalls when the sensor fails. These intermittent failures may not immediately set diagnostic codes.
EVAP System Flooding
If the EVAP purge valve is stuck open, excessive fuel vapors flood the engine continuously. The engine may fire, run briefly, then stall from over-rich conditions. This is often worse after refueling when vapor levels are highest.