Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Fuel System Overview
The fuel system is an electronic returnless on-demand design. A returnless fuel system reduces the internal temperature of the fuel tank by not returning hot fuel from the engine to the fuel tank. Reducing the internal temperature of the fuel tank results in lower evaporative emissions.
An electric three-phase style fuel pump attaches to the A7 Fuel Tank Fuel Pump Moduleinside the fuel tank. The fuel pump supplies fuel through the fuel feed pipe to the High Pressure Fuel Pump. The High Pressure Fuel Pump supplies fuel to a variable-pressure fuel rail. Fuel enters the combustion chamber through precision multi-hole fuel injectors. The High Pressure Fuel Pump, fuel rail pressure, fuel injection timing, and injection duration are controlled by the Powertrain Control Module (PCM).
The A7 Fuel Tank Fuel Pump Modulealso contains a primary jet pump. Fuel pump flow loss, caused by vapor expulsion in the pump inlet chamber, is diverted to the primary jet pump through a restrictive orifice located on the pump cover. The primary jet pump fills the reservoir of the A7 Fuel Tank Fuel Pump Module. On models equipped with All-Wheel Drive, the A7 Fuel Tank Fuel Pump Modulehas a secondary jet pump that creates a venturi action which causes the fuel to be drawn from the secondary side of the fuel tank, through the fuel transfer hose, to the primary side of the fuel tank.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.