How to Determine if the Fuel Metering Unit is Damaged?
3 Answers
It will cut off the fuel injection to the engine, and continued use may cause the engine to malfunction. It may result in stalling or black smoke emissions. In the electronic fuel injection system, the fuel metering unit is an indispensable component.
I drive frequently and have experienced fuel metering unit failures. The symptoms are usually obvious: the car struggles excessively to start, requiring prolonged key turning for a reluctant ignition; severe idling vibrations make the entire body shake; and there's noticeable power loss during acceleration, with the gas pedal feeling unresponsive like stepping on cotton. When these signs appear, I suspect the fuel pump unit—responsible for delivering fuel to the engine. A simple test method: before starting, turn the key to the ON position without igniting, then crouch near the fuel tank at the rear and listen carefully for a brief humming sound (normally lasting 1-2 seconds). Silence likely indicates pump failure. I’ve also noticed symptoms worsening after refueling, as low fuel levels cause the pump to overheat. Upon detection, visit a repair shop promptly for professional diagnostics—e.g., using a pressure gauge on the fuel rail to check if readings fall below the standard range (typically 40-60 psi) or scanning OBD trouble codes. Avoid delays; a roadside failure is troublesome. Regular maintenance, including fuel filter replacement, extends the unit’s lifespan.
As someone who frequently tinkers with cars, I have several practical methods for diagnosing fuel metering unit failures. Mainly look for symptoms: difficulty starting the vehicle, unstable idling accompanied by noticeable shaking, sluggish acceleration as if power is being choked. These are classic signs of a fuel pump unit failing to supply fuel properly. During testing, first listen carefully—after turning the key to the ON position, check if there's a brief humming sound near the fuel tank; no sound warns of unit failure. Next, inspect the fuel pump relay and fuse to ensure the circuit isn't broken but the pump isn't functioning. If you have the tools, connect a fuel pressure gauge to the engine's fuel rail test port to measure pressure values; standard values vary by vehicle model, but abnormally low pressure (e.g., below 30 psi or zero) indicates a failed unit. An OBD scanner reading fault codes is also useful—codes like P0087 (fuel pressure too low) often help confirm the issue. Additionally, note that problems are more likely to occur during cold starts or hot weather. Early inspection prevents roadside breakdowns; it's recommended to visit a workshop for a comprehensive diagnostic with professional equipment.
