ADT ADT Fuel System & Injection Technology

Question 1

Audi's TFSI engine technology combines which two fuel delivery methods to improve efficiency and performance?

Accepted Answer

Turbocharging and Gasoline Fuel Stratified Injection (direct injection)

Answer

TFSI stands for Turbocharged Fuel Stratified Injection, combining a turbocharger with gasoline direct injection for precise fuel delivery.

Question 2

On Audi FSI/TFSI engines, the high-pressure fuel pump is driven by:

Accepted Answer

A lobe on the camshaft

Answer

The high-pressure fuel pump on FSI/TFSI engines is mechanically actuated by a dedicated lobe on the intake or exhaust camshaft.

Question 3

What is the typical high-pressure fuel rail operating pressure range for Audi TFSI direct injection engines?

Accepted Answer

50–200 bar

Answer

Audi TFSI direct injection systems operate at 50–200 bar of fuel rail pressure, far higher than conventional port injection systems.

Question 4

A customer's Audi A4 2.0 TFSI exhibits rough idle and misfires at cold start. A known common cause on this engine is:

Accepted Answer

Carbon buildup on intake valves due to direct injection without port wash

Answer

Direct injection engines do not wash the intake valves with fuel, so oil vapor from the PCV system causes carbon deposits, leading to cold-start misfires.

Question 5

When diagnosing a low fuel pressure code on an Audi TFSI, a technician should verify which component FIRST?

Accepted Answer

The low-pressure fuel pump (in-tank pump) output pressure

Answer

The in-tank low-pressure pump feeds the high-pressure pump; insufficient low-side pressure will prevent the high-pressure pump from meeting rail pressure targets.

(ADT) Audi Diagnostic Technician Practice Test

(ADT) Audi Diagnostic Technician Practice Test

ADT ADT Fuel System & Injection Technology