Responding to an Italian customer's inquiry about the Volvo V50 usage：La mia volvo V50 1600 benzina metano al semaforo verte volte si spegne il motore
It sounds like your Volvo V50 1.6 Bi-Fuel (Petrol & CNG) is stalling sometimes when stopped at traffic lights. Here are some possible reasons and solutions:
Possible Causes & Solutions:
Idle Control Valve (IAC) / Throttle Body Issues
A dirty or faulty idle control valve or throttle body could cause unstable idling and stalling.
Try cleaning the throttle body and the idle control system.
CNG System Issues
If the problem only happens while running on CNG, the injectors, pressure regulator, or gas filter may be clogged or faulty.
Try switching to petrol mode and see if the problem continues. If not, service the CNG system.
Fuel Delivery Problems
A weak or failing fuel pump or a clogged fuel filter (for both petrol and CNG) could cause the engine to stall.
Replace the fuel filter if it hasn't been changed recently.
Air Intake & Vacuum Leaks
A vacuum leak in the intake system can cause erratic idling and stalling.
Check for cracked hoses or leaks in the intake manifold.
Sensors (MAF, MAP, Crankshaft Position Sensor)
A faulty Mass Airflow Sensor (MAF) or Manifold Absolute Pressure (MAP) sensor can cause unstable idle and stalling.
A failing crankshaft position sensor could also lead to the engine cutting off unexpectedly.
What You Can Do:
✅ Scan for error codes with an OBD2 scanner.
✅ Try cleaning the throttle body and checking for vacuum leaks.
✅ If the issue happens only in CNG mode, have a mechanic check the CNG injectors, pressure regulator, and filter.
✅ If it happens in both CNG and petrol modes, check the idle control system and sensors.
