To diagnose a fuel pump issue in a 2019 Honda Accord, follow these detailed steps:

Understand the Symptoms of a Faulty Fuel Pump

• Engine Sputtering at High Speeds: The fuel pump may be unable to deliver a consistent fuel supply.
• Decreased Fuel Efficiency: A faulty pump may lead to improper fuel delivery, affecting fuel economy.
• Car Surging: This is caused by irregular fuel flow.
• Difficulty Starting: This could be due to inadequate fuel pressure.
• Car Not Starting: Complete failure to start may point to a total pump failure.

Check the Fuel Pump Relay and Fuse

• Locate the fuel pump relay and fuse in the engine compartment fuse box. Refer to the car's manual for specifics.
• Examine the fuse for any visible breaks or burns; replace it if necessary.
• Test the relay by swapping it with a similar one from the fuse box to see if the problem is resolved.

Listen for the Fuel Pump Activation

• Turn the ignition key to the "On" position without starting the engine.
• Listen near the rear of the car for a humming sound, which indicates the fuel pump is engaging properly.
• If there's no sound, the fuel pump may be faulty.

Conduct a Fuel Pressure Test

• Tools Required: Fuel pressure gauge, safety goggles, and gloves.
• Locate the Schrader valve on the fuel rail and attach the fuel pressure gauge.
• Start the engine or turn the key to "On".
• Read the pressure gauge: Compare it with the specifications in the vehicle's manual.
• Low pressure readings may indicate a failing fuel pump, whereas no pressure reading could mean a complete failure.

Inspect the Fuel Lines and Fuel Filter

• Check for visible leaks or blockages in the fuel lines.
• Examine the fuel filter for clogs which may mimic pump failure symptoms.
• Replace the fuel filter regularly to prevent misinformation on fuel pump performance.

Electrical Connection and Wiring Check

• Inspect wiring and connectors to the fuel pump for corrosion or damage.
• Ensure all connections are secure and that there are no loose or frayed wires.

Consider a Professional Diagnostic

• If initial checks are inconclusive, consult with a qualified mechanic.
• Use of advanced diagnostic tools may be necessary for in-depth evaluation.
• Professional diagnostics can identify electronic issues related to the fuel pump system.

Through these steps, you should be able to determine whether the fuel pump in your 2019 Honda Accord is the source of any performance issues. If unsure, it’s always advisable to seek professional assistance to prevent unnecessary replacements and ensure the vehicle's reliability.