Fuel
Fuel Pump
The fuel pump moves fuel from the tank to the engine, often at very high pressure in direct injection.
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Fuel delivery flow
Interactive — tap a partTap a part to see how it fits in the system.
What it does
- Delivers fuel from the tank to the rail
- Maintains constant system pressure
- In-tank pumps are electric; direct injection adds a high-pressure pump
When it fails
- No fuel pump whine when the key is turned ON
- Hard starting
- Engine cuts out under load
- Loss of power on hills
How to diagnose
- Listen for the pump at key ON
- Measure fuel pressure against spec
- Test fuel pressure hold after shutdown
- Check the pump relay and fuse
Maintenance
- Keep the tank above a quarter to cool the pump
- Change the fuel filter on schedule
- Fix fuel leaks immediately
Use the diagnosis order. When a part fails, confirm each hypothesis with measurements before replacing anything — codes and symptoms overlap.
Related part
Fuel Filter
The fuel filter removes dirt and water before fuel reaches the pump or injectors.