Stalling happens when the engine cannot maintain idle RPM. It is caused by disruptions in air, fuel, spark, or sensor feedback.
1. Idle Air Control Valve Failure
The IAC valve controls idle airflow.
If faulty
-
Engine stalls at idle
-
RPM hunts up and down
-
Common in Toyota, Honda, Subaru
2. Vacuum Leaks
Air leaks disrupt fuel mixture.
Effects
-
Lean condition
-
Stall during idle
-
P0171/P0174 codes
3. Weak Fuel Pump
A failing pump cannot sustain minimum operating pressure.
Symptoms
-
Hard starting
-
Stalling under load
-
Low-pressure readings
4. Crankshaft Position Sensor Failure
The crank sensor tells the ECU when to fire spark and inject fuel.
Facts
-
If it fails, the engine dies instantly
-
Common in Nissan, BMW, Hyundai
5. EGR Valve Stuck Open
Allows too much exhaust into the intake.
Results
-
Rough idle
-
Frequent stalling
-
Poor combustion
Conclusion
Stalling is caused by airflow disruptions, sensor failures, fuel delivery issues, or idle control faults. Diagnostics require scanning codes and monitoring fuel and airflow data.
Comments
Post a Comment